L18 endocrine system
1. Nervous system and endocrine system
• The nervous and endocrine systems act as a coordinated interlocking supersystem, the neuroendocrine system.
• The endocrine system controls body activities by releasing mediator molecules called hormones.
– hormones released into the bloodstream travel throughout the body
– results may take hours, but last longer
• The nervous system controls body actions through nerve impulses.
– certain parts release hormones into blood
– rest releases neurotransmitters excite or inhibit nerve, muscle & gland cells
– results in milliseconds, brief duration of effects
• The nervous system causes muscles to contract or glands to secrete. The endocrine system affects virtually all body tissues by altering metabolism, regulating growth and development, and influencing reproductive processes.
• Parts of the nervous system stimulate or inhibit the release of hormones.
• Hormones may promote or inhibit the generation of nerve impulses.
• General Functions of Hormones:
• Help regulate:
– extracellular fluid
– metabolism
– biological clock
– contraction of cardiac & smooth muscle
– glandular secretion
– some immune functions
• Growth & development
• Reproduction
• Hormones have powerful effects when present in very low concentrations.
Endocrine Glands Defined
• Exocrine glands
– secrete products into ducts which empty into body cavities or body surface
– sweat, oil, mucous, & digestive glands
• Endocrine glands
– secrete products (hormones) into bloodstream
– pituitary, thyroid, parathyroid, adrenal, pineal
– other organs secrete hormones as a 2nd function
– hypothalamus, thymus, pancreas,ovaries,testes, kidneys, stomach, liver, small intestine, skin, heart & placenta
2. Circulating & Local Hormones
• Circulating hormones
• Local hormones
– paracrines
– Autocrines
• Hormones only affect target cells with specific membrane proteins called receptors
3. Lipid-soluble Hormones
• Steroids
– lipids derived from cholesterol on SER
• Thyroid hormones
– tyrosine ring plus attached iodines are lipid-soluble
4. Water-soluble Hormones
•Amine, peptide and protein hormones
–modified amino acids or amino acids put together serotonin, melatonin, histamine, epinephrine some glycoproteins
5. General Mechanisms of Hormone Action
• Hormone binds to cell surface or receptor inside target cell
• Cell may then
– synthesize new molecules
– change permeability of membrane
– alter rates of reactions
• Each target cell responds to hormone differently
At liver cells---insulin stimulates glycogen synthesis
At adipocytes---insulin stimulates triglyceride synthesis
6. Control of Hormone Secretion
• Regulated by signals from nervous system, chemical changes in the blood or by other hormones
• Negative feedback control (most common)
– decrease/increase in blood level is reversed
• Positive feedback control
– the change produced by the hormone causes more hormone to be released
• Disorders involve either hyposecretion or hypersecretion of a hormone
7. HYPOTHALAMUS AND PITUITARY GLAND
• The hypothalamus is the major integrating link between the nervous and endocrine systems.
• The hypothalamus and the pituitary gland (hypophysis) regulate virtually all aspects of growth, development, metabolism, and homeostasis.
• Anterior Pituitary Gland (Adenohypophysis)
– The blood supply to the anterior pituitary is from the superior hypophyseal arteries.
– Hormones of the anterior pituitary and the cells that produce the:
• Human growth hormone (hGH)
• Thyroid-stimulating hormone (TSH)
• Follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
• Prolactin (PRL) Adrenocorticotrophic hormone (ACTH) and melanocyte-stimulating hormone (MSH)
8. Flow of Blood to Anterior Pituitary
• Controlling hormones enter blood
• Travel through portal veins
• Enter anterior pituitary at capillaries
9. Anterior Pituitary
Secretion of anterior pituitary gland hormones is regulated by hypothalamic regulating hormones and by negative feedback mechanisms
10. Negative Feedback Systems
• Decrease in blood levels
• Receptors in hypothalamus & thyroid
• Cells activated to secrete more TSH or more T3 & T4
• Blood levels increase
11. Positive Feedback
• Oxytocin stimulates uterine contractions
• Uterine contractions stimulate oxytocin release
12. Human Growth Hormone and Insulin-like Growth Factors
• It acts indirectly on tissues by promoting the synthesis and secretion of small protein hormones called insulin-like growth factors (IGFs).
– IGFs stimulate general body growth and regulate various aspects of metabolism.
– Various stimuli promote and inhibit hGH production
• target cells synthesize insulinlike growth
– common target cells are liver, skeletal muscle, cartilage and bone
– increases cell growth & cell division by increasing their uptake of amino acids & synthesis of proteins
– stimulate lipolysis in adipose so fatty acids used for ATP
– retard use of glucose for ATP production so blood glucose levels remain high enough to supply brain
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1. Thyroid Stimulating Hormone (TSH)
• Hypothalamus regulates thyrotroph cells
• Thyrotroph cells produce TSH
• TSH stimulates the synthesis & secretion of T3 and T4
• Metabolic rate stimulated
2. Follicle Stimulating Hormone (FSH)
• Releasing hormone from hypothalamus controls gonadotrophs
• Gonadotrophs release follicle stimulating hormone
• FSH functions
– initiates the formation of follicles within the ovary
– stimulates follicle cells to secrete estrogen
– stimulates sperm production in testes
3. Luteinizing Hormone (LH)
• Releasing hormones from hypothalamus stimulate gonadotrophs
• Gonadotrophs produce LH
• In females, LH stimulates
– secretion of estrogen
– ovulation of 2nd oocyte from ovary
– formation of corpus luteum
– secretion of progesterone
• In males, LH stimulates the interstitial cells of the testes to secrete testosterone.
4. Prolactin (PRL)
• Prolactin (PRL), together with other hormones, initiates and maintains milk secretion by the mammary glands.
– Hypothalamus regulates lactotroph cells
– Lactotrophs produce prolactin
– Under right conditions, prolactin causes milk production
5. Adrenocorticotrophic Hormone
• Adrenocorticotrophic hormone (ACTH) controls the production and secretion of hormones called glucocorticoids by the cortex of the adrenal gland.
– Hypothalamus releasing hormones stimulate corticotrophs
– Corticotrophs secrete ACTH & MSH
– ACTH stimulates cells of the adrenal cortex that produce glucocorticoids
6. Melanocyte-Stimulating Hormone
• Melanocyte-stimulating hormone (MSH) increases skin pigmentation although its exact role in humans is unknown.
– Releasing hormone from hypothalamus increases MSH release from the anterior pituitary
– Secreted by corticotroph cells
7. Posterior Pituitary Gland (Neurohypophysis)
• Does not synthesize hormones
• Neurons release two neurotransmitters into capillaries
– antidiuretic hormone
– oxytocin
8. Oxytocin
• Two target tissues both involved in neuroendocrine reflexes
• During delivery
– baby’s head stretches cervix
– hormone release enhances uterine muscle contraction
– baby & placenta are delivered
• After delivery
– Oxytocin stimulates contraction of the uterus and ejection (let-down) of milk from the breasts.
9. Antidiuretic Hormone (ADH)
• Antidiuretic hormone stimulates water reabsorption by the kidneys and arteriolar constriction.
• The effect of ADH is to decrease urine volume and conserve body water.
• ADH is controlled primarily by osmotic pressure of the blood .
• Functions
– decrease urine production
– decrease sweating
– increase BP
10. Thyroid Gland
• The thyroid gland is located just below the larynx and has right and left lateral lobes.
• Histologically, the thyroid consists of the thyroid follicles composed of follicular cells, which secrete the thyroid hormones thyroxine (T4) and triiodothyronine (T3), and parafollicular cells, which secrete calcitonin (CT)
• On each side of trachea is lobe of thyroid
• has rich blood supply
11. Photomicrograph of Thyroid Gland
12. Actions of Hormones from Thyroid Gland
• T3 & T4
– thyroid hormones responsible for our metabolic rate, synthesis of protein, breakdown of fats, use of glucose for ATP production
• Calcitonin
– responsible for building of bone & stops reabsorption of bone (lowers blood levels of Calcium)
13. PARATHYROID GLANDS
• The parathyroid glands are embedded on the posterior surfaces of the lateral lobes of the thyroid
• Parathyroid hormone (PTH) regulates the homeostasis of calcium and phosphate
• increase blood calcium level
• decrease blood phosphate level
– increases the number and activity of osteoclasts
– increases the rate of Ca+2 and Mg+2 from reabsorption from urine and inhibits the reabsorption of HPO4 -2 so more is secreted in the urine
– promotes formation of calcitriol, which increases the absorption of Ca+2, Mg+2 ,and HPO4 -2 from the GI tract
• 4 pea-sized glands found on back of thyroid gland
14. Adrenal Glands
• The adrenal glands are located superior to the kidneys
• The adrenal cortex secretes hormones .
• Mineralocorticoids
– 95% of hormonal activity due to aldosterone
– Functions
• increase reabsorption of Na+ with Cl- , bicarbonate and water following it
• promotes excretion of K+ and H+
• high blood pressure caused by retention of Na+ and water in blood
• Androgens
– Small amount of male hormone produced
– insignificant in males
– may contribute to sex drive in females
– is converted to estrogen in postmenopausal females
• glucocorticoids.
• Medulla produces epinephrine & norepinephrine
15. Histology of Adrenal Gland
• Cortex
– 3 zones
• Medulla
16. Adrenal Medulla
• Produce epinephrine & norepinephrine
• Hormones are sympathomimetic
– effects mimic those of sympathetic NS
– cause fight-flight behavior
• Acetylcholine increase hormone secretion by adrenal medulla
17. Anatomy of Pancreas
• The pancreas is a flattened organ located posterior and slightly inferior to the stomach and can be classified as both an endocrine and an exocrine gland.
• Cells (99%) in acini produce digestive enzymes
• Endocrine cells in pancreatic islets produce hormones
18. Ovaries and Testes
• Ovaries
– estrogen, progesterone, relaxin & inhibin
– regulate reproductive cycle, maintain pregnancy & prepare mammary glands for lactation
• Testes
– produce testosterone
– regulate sperm production & 2nd sexual characteristics
19. Pineal Gland
• Consists of pinealocytes & neuroglia
• Melatonin responsible for setting of biological clock
• Melatonin secretion producing sleepiness occurs during darkness due to lack of stimulation from sympathetic ganglion
20. Thymus Gland
• Important role in maturation of T cells
• Hormones produced by gland promote the proliferation & maturation of T cell
L19 Blood
1. Introduction
• Blood inside blood vessels
• To obtain nutrients and remove wastes, cells must be serviced by blood and interstitial fluid.
• Blood, a connective tissue, is composed of plasma and formed elements.
• The branch of science concerned with the study of blood, blood-forming tissues, and the disorders associated with them is called hematology.
2. Functions of Blood
• Transportation
– O2, CO2, metabolic wastes, nutrients, heat & hormones
• Regulation
– helps regulate pH through buffers
– helps regulate body temperature
– helps regulate water content of cells by interactions with dissolved ions and proteins
• Protection from disease & loss of blood
3. Components of Blood
• Hematocrit
– plasma
– cells
• Blood plasma consists of water and solutes.
4. Blood Plasma
• 0ver 90% water
• 7% plasma proteins
• created in liver
• confined to bloodstream
– albumin
• maintain blood osmotic pressure
– globulins (immunoglobulins)
• antibodies bind to foreign substances called antigens
• form antigen-antibody complexes
– fibrinogen
• for clotting
• 2% other substances
– electrolytes, nutrients, hormones, gases, waste products
5. Red blood cell or erythrocytes
• Contain oxygen-carrying protein hemoglobin that gives blood its red color
• Biconcave
– increased surface area/volume ratio
– flexible shape for narrow passages
– no nucleus or other organelles
• Worn out cells removed by fixed macrophages in spleen & liver
6. White blood cell
• All WBCs (leukocytes) have a nucleus and no hemoglobin
• Granular or agranular classification based on presence of cytoplasmic granules made visible by staining
– granulocytes are neutrophils, eosinophils or basophils
– agranulocytes are monocytes or lymphocytes
7. Neutrophils (Granulocyte)
• Nuclei = 2 to 5 lobes connected by thin strands
• Neutrophils and wandering or fixed macrophages (which develop from monocytes) do so through phagocytosis.
• Fastest response of all WBC to bacteria
8. Eosinophils (Granulocyte)
• Nucleus with 2 or 3 lobes connected by a thin strand
• Large, uniform-sized granules stain orange-red with acidic dyes
• Leave capillaries to enter tissue fluid
• Release histaminase
– slows down inflammation caused by basophils
• Attack parasitic worms
• Phagocytize antibody-antigen complexes
9. Basophils (Granulocyte)
• Large, dark purple, variable-sized granules stain with basic dyes
• Irregular, s-shaped, bilobed nuclei
• Involved in inflammatory and allergy reactions
• Leave capillaries & enter connective tissue as mast cells
• Release heparin, histamine & serotonin
10. Lymphocyte (Agranulocyte)
• Dark, oval to round nucleus
• Cytoplasm sky blue in color
– amount varies from rim of blue to normal amount
• B cells
– destroy bacteria and their toxins
– turn into plasma cells that produces antibodies
• T cells
– attack viruses, fungi, transplanted organs, cancer cells & some bacteria
• Natural killer cells
– attack many different microbes & some tumor cells
– destroy foreign invaders by direct attack
11. Monocyte (Agranulocyte)
• Nucleus is kidney or horse-shoe shaped
• Largest WBC in circulating blood
– does not remain in blood long before migrating to the tissues
– differentiate into macrophages
• macrophages, are active in phagocytosis.
• Destroy microbes and clean up dead tissue following an infection
• Take longer to get to site of infection, but arrive in larger numbers
12. Platelet (Thrombocyte)
• Platelets help stop blood loss from damaged vessels by forming a platelet plug.
• Their granules also contain chemicals that promote blood clotting.
• Disc-shaped, 2 - 4 micron cell fragment with no nucleus
13. Hemostasis
• A clot is a gel consisting of a network of insoluble protein fibers (fibrin) in which formed elements of blood are trapped
• The chemicals involved in clotting are known as coagulation (clotting) factors; most are in blood plasma, some are released by platelets, and one is released from damaged tissue cells
• Blood clotting involves a cascade of reactions that may be divided into three stages:
– formation of prothrombinase (prothrombin activator)
– conversion of prothrombin into thrombin
– conversion of soluble fibrinogen into insoluble fibrin
• The clotting cascade can be initiated by either the extrinsic pathway or the intrinsic pathway.
• Normal coagulation requires vitamin K and also involves clot retraction (tightening of the clot) and fibrinolysis (dissolution of the clot).
• The fibrinolytic system dissolves small, inappropriate clots and clots at a site of damage once the damage is repaired.
• Plasmin (fibrinolysin) can dissolve a clot by digesting fibrin threads and inactivating substances such as fibrinogen, prothrombin, and factors V, VIII, and XII.
• Stoppage of bleeding in a quick & localized fashion when blood vessels are damaged
• Prevents hemorrhage (loss of a large amount of blood)
• Methods utilized
– vascular spasm
– platelet plug formation
– blood clotting (coagulation = formation of fibrin threads)
14. Vascular Spasm/vasoconstriction
• Damage to blood vessel produces stimulates pain receptors
• Reflex contraction of smooth muscle of small blood vessels
• Can reduce blood loss for several hours until other mechanisms can take over
• Only for small blood vessel or arteriole
15. Platelet Plug Formation
• Steps in the process
– (1) platelet adhesion (2) platelet release reaction (3) platelet aggregation
• Platelets stick to exposed collagen underlying damaged endothelial cells in vessel wall
• Extend projections to make contact with each other
• Release thromboxane A2 & ADP are vasoconstrictors decreasing blood flow through the injured vessel
• Activated platelets stick together and activate new platelets to form a mass called a platelet plug
16. Blood Clotting
• Blood drawn from the body thickens into a gel
– gel separates into liquid (serum) and a clot of insoluble fibers (fibrin) in which the cells are trapped
• If clotting occurs in an unbroken vessel is called a thrombosis
• Substances required for clotting are Ca+2, enzymes synthesized by liver cells and substances released by platelets or damaged tissues
• Clotting is a cascade of reactions in which each clotting factor activates the next in a fixed sequence resulting in the formation of fibrin threads
– prothrombinase & Ca+2 convert prothrombin into thrombin
– thrombin converts fibrinogen into fibrin threads
17. Clot Retraction & Blood Vessel Repair
• Clot plugs ruptured area of blood vessel
• Platelets pull on fibrin threads causing clot retraction
• Edges of damaged vessel are pulled together
• Fibroblasts & endothelial cells repair the blood vessel
https://www.youtube.com/watch?v=zOvq1x9rbt4
18. Hemostatic Control Mechanisms
• Fibrinolytic system dissolves small, inappropriate clots & clots at a site of a completed repair
– fibrinolysis is dissolution of a clot
• Inactive plasminogen is incorporated into the clot
– plasminogen becomes plasmin (fibrinolysin) which digests fibrin threads
• Clot formation remains localized
– fibrin absorbs thrombin
– blood disperses clotting factor
• Anticoagulants present in blood & produced by mast cells
• Clots are generally localized due to fibrin absorbing thrombin into the clot, clotting factors diffusing through blood, and the production of prostacyclin, a powerful inhibitor of platelet adhesion and release.
• Substances that inhibit coagulation, called anticoagulants, are also present in blood. An example is heparin.
• Despite the anticoagulating and fibrinolytic mechanisms, blood clots sometimes form within the cardiovascular system.
• Clotting in an unbroken blood vessel is called thrombosis (unwanted blood clot).
• A thrombus (clot), bubble of air, fat from broken bones, or piece of debris transported by the bloodstream that moves from its site of origin is called an embolus.
SUMMARY:
https://www.youtube.com/watch?v=xEHGIRpGyh4
https://www.youtube.com/watch?v=R8JMfbYW2p4
https://www.youtube.com/watch?v=qWSWWPZYGHU
https://www.youtube.com/watch?v=qrE6Y0Se8bw
https://www.youtube.com/watch?v=VSVYgivfs9c
https://www.youtube.com/watch?v=W9kGIaGG5Lc&t=195s
https://www.youtube.com/watch?v=aVd7OnG4c3c
https://www.youtube.com/watch?v=x8TLTTyyPfI
https://www.youtube.com/watch?v=7VubLcJqniY
https://www.youtube.com/watch?v=PK5YbDZODYk
L20 The Cardiovascular System: The Heart
1. Cardiology
• The study of the normal heart and diseases associated with it is known as cardiology.
2. Heart Location
• The heart is situated between the lungs in the mediastinum with about two-thirds of its mass to the left of the midline
• Heart is located in the mediastinum
– area from the sternum to the vertebral column and between the lungs
3. Heart Orientation
• Apex - directed anteriorly, inferiorly and to the left
• Base - directed posteriorly, superiorly and to the right
• Anterior surface - deep to the sternum and ribs
• Inferior surface - rests on the diaphragm
• Right border - faces right lung
• Left border (pulmonary border) - faces left lung
4. Pericardium
• The heart is enclosed and held in place by the pericardium.
– The pericardium consists of an outer fibrous pericardium and an inner serous pericardium (epicardium.
– Between the parietal and visceral layers of the serous pericardium is the pericardial cavity,
• Fibrous pericardium
– protects and anchors the heart, prevents overstretching
• Serous pericardium
– thin delicate membrane
5. Layers of Heart Wall
• The wall of the heart has three layers: epicardium, myocardium, and endocardium
• Epicardium
– visceral layer of serous
pericardium
– mesothelium and connective tissue
• Myocardium
– cardiac muscle layer is the bulk of the heart
• Endocardium
– endothelium and connective tissue
– chamber lining & valves
6. Chambers and Sulci of the Heart .
• Four chambers
– 2 upper atria
– 2 lower ventricles
• Sulci - grooves on surface of heart containing coronary blood vessels and fat
– coronary sulcus
• encircles heart and marks the boundary between the atria and the ventricles
– anterior interventricular sulcus
• marks the boundary between the ventricles anteriorly
– posterior interventricular sulcus
• marks the boundary between the ventricles posteriorly
7. Right Atrium
• Receives blood from 3 sources
– superior vena cava, inferior vena cava and coronary sinus
• Tricuspid valve
– Blood flows through into right ventricle
– has three cusps composed of dense CT covered by endocardium
8. Right Ventricle
• Forms most of anterior surface of heart
• Interventricular septum: partitions ventricles
• Pulmonary semilunar valve: blood flows into pulmonary trunk
9. Left Atrium
• Forms most of the base of the heart
• Receives blood from lungs - 4 pulmonary veins (2 right + 2 left)
• Bicuspid valve: blood passes through into left ventricle
– has two cusps
– to remember names of this valve, try the pneumonic LAMB
• Left Atrioventricular, Mitral, or Bicuspid valve
10. Left Ventricle
• Forms the apex of heart
• Aortic semilunar valve:
– blood passes through valve into the ascending aorta
– just above valve are the openings to the coronary arteries
11. Myocardial Thickness and Function
• Thickness of myocardium varies according to the function of the chamber
• Atria are thin walled, deliver blood to adjacent ventricles
• Ventricle walls are much thicker and stronger
– right ventricle supplies blood to the lungs (little flow resistance)
– left ventricle wall is the thickest to supply systemic circulation
• Myocardium of left ventricle is much thicker than the right.
12. Fibrous Skeleton of Heart
• Dense CT rings surround the valves of the heart, fuse and merge with the interventricular septum
– Support structure for heart valves
– Insertion point for cardiac muscle bundles
– Electrical insulator between atria and ventricles
13. Atrioventricular Valves Open & Close
• A-V valves open and allow blood to flow from atria into ventricles when ventricular pressure is lower than atrial pressure
– occurs when ventricles are relaxed, chordae tendineae are slack and papillary muscles are relaxed
• A-V valves close preventing backflow of blood into atria
– occurs when ventricles contract, pushing valve cusps closed, chordae tendinae are pulled taut and papillary muscles contract to pull cords and prevent cusps from everting
14. Semilunar Valves
• SL valves open with ventricular contraction
– allow blood to flow into pulmonary trunk and aorta
• SL valves close with ventricular relaxation
– prevents blood from returning to ventricles, blood fills valve cusps, tightly closing the SL valves
15. Blood Circulation
• Two closed circuits, the systemic and pulmonic
• Systemic circulation-left-O2-body
– left side of heart pumps blood through body
– left ventricle pumps oxygenated blood into aorta
– aorta branches into many arteries that travel to organs
– arteries branch into many arterioles in tissue
– arterioles branch into thin-walled capillaries for exchange of gases and nutrients-O2 to CO2
– deoxygenated blood begins its return in venules
– venules merge into veins and return to right atrium
• Blood flow
– blue = deoxygenated
– red = oxygenated
• Pulmonary circulation-right-deO2-lungs
– right side of heart pumps deoxygenated blood to lungs
– right ventricle pumps blood to pulmonary trunk
– pulmonary trunk branches into pulmonary arteries
– pulmonary arteries carry blood to lungs for exchange of gases-CO2 to O2
– oxygenated blood returns to heart in pulmonary veins
16. Coronary Circulation
• The flow of blood through the many vessels that flow through the myocardium of the heart is called the coronary (cardiac) circulation;
• it delivers oxygenated blood and nutrients to and removes carbon dioxide and wastes from the myocardium
• Coronary circulation is blood supply to the heart
• Heart as a very active muscle needs lots of O2
• When the heart relaxes high pressure of blood in aorta pushes blood into coronary vessels
Coronary Arteries
• Branches off aorta above aortic semilunar valve
• Left coronary artery
• Right coronary artery
Coronary Veins
• Collects wastes from cardiac muscle
• Drains into a large sinus on posterior surface of heart called the coronary sinus
• Coronary sinus empties into right atrium
SUMMARY:
https://www.youtube.com/watch?v=PsOwWGWsJIs
https://www.youtube.com/watch?v=28CYhgjrBLA
https://www.youtube.com/watch?v=ebzbKa32kuk
https://www.youtube.com/watch?v=6u4Hcbtw1gw
https://www.youtube.com/watch?v=WBwPhWAP394
https://www.youtube.com/watch?v=BEWjOCVEN7M
https://www.youtube.com/watch?v=_qmNCJxpsr0
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1. Conduction System of Heart
Coordinates contraction of heart muscle.
• Autorhythmic Cells
– Cells fire spontaneously, act as pacemaker and form conduction system for the heart
• SA node
– cluster of cells in wall of Rt. (Right) Atria
– begins heart activity that spreads to both atria
– excitation spreads to AV node
• AV node
– in atrial septum, transmits signal to bundle of His
• AV bundle of His
– the connection between atria and ventricles
– divides into bundle branches & purkinje fibers, large diameter fibers that conduct signals quickly
https://www.youtube.com/watch?v=Lt092HZCppo
https://www.youtube.com/watch?v=TnFoJ7Hhi-M
2. Autorhythmic Cells: The Conduction System
• Cardiac muscle cells are autorhythmic cells because they are self-excitable. They repeatedly generate spontaneous action potentials that then trigger heart contractions.
• These cells act as a pacemaker to set the rhythm for the entire heart.
• They form the conduction system, the route for propagating action potential through the heart muscle.
3. Physiology of Contraction
• Depolarization, plateau, repolarization, Refractory period
Depolarization & Repolarization
• Depolarization
– Cardiac cell resting membrane potential is -90mv
– excitation spreads through gap junctions
– fast Na+ channels open for rapid depolarization
• Plateau phase
– slow Ca+2 channels open, let Ca +2 enter from outside cell and from storage in sarcoplasmic reticulum, while K+ channels close
– Ca +2 binds to troponin to allow for actin-myosin cross-bridge formation & tension development
• Repolarization
– Ca+2 channels close and K+ channels open & -90mv is restored as potassium leaves the cell
• Refractory period
– very long so heart can fill
4. Electrocardiogram---ECG or EKG
• Impulse conduction through the heart generates electrical currents that can be detected at the surface of the body.
• EKG
– A recording of the electrical changes that accompany each cardiac cycle (heartbeat)
• P wave
– atrial depolarization
• P to Q interval
– conduction time from atrial to ventricular excitation
• QRS complex
– ventricular depolarization
• T wave
– ventricular repolarization
https://www.youtube.com/watch?v=RYZ4daFwMa8
5. Cardiac cycle
• A cardiac cycle consists of the systole (contraction) and diastole (relaxation) of both atria, rapidly followed by the systole and diastole of both ventricles.
• Pressure and volume changes during the cardiac cycle
• During a cardiac cycle atria and ventricles alternately contract and relax forcing blood from areas of high pressure to areas of lower pressure.
• At 75 beats/min, one cycle requires 0.8 sec.
– systole (contraction) and diastole (relaxation) of both atria, plus the systole and diastole of both ventricles
6. Phases of Cardiac Cycle
• Isovolumetric relaxation
– brief period when volume in ventricles does not change--as ventricles relax, pressure drops and Atrioventricular valves open
• Ventricular filling
– rapid ventricular filling:as blood flows from full atria
– diastasis: as blood flows from atria in smaller volume
– atrial systole pushes final 20-25 ml blood into ventricle
• Ventricular systole
– ventricular systole
– isovolumetric contraction
• brief period, Atrioventricular valves close before Semilunar valves open
– ventricular ejection: as Semilunar valves open and blood is ejected
7. Atrial systole/ventricular diastole
• The atria contract, increasing pressure forces the AV valves to open.
– The amount of blood in the ventricle at the end of diastole is the End Diastolic Volume (EDV)
• Ventricular systole/atrial diastole
– Ventricles contract and increasing pressure forces the Atrioventricular valves to close.
– Atrioventricular and Semilunar valves are all closed (isovolumetric contraction).
– Pressure continues to rise opening the Semilunar valves leading to ventricular ejection.
8. Relaxation period
• Both atria and ventricles are relaxed. Pressure in the ventricles fall and the Semilunar valves close. Brief time all four valves are closed is the isovolumetric relaxation. Pressure in the ventricles continues to fall, the AV valves open, and ventricular filling begins.
9. Auscultation
• The act of listening to sounds within the body is called auscultation, and it is usually done with a stethoscope. The sound of a heartbeat comes primarily from the turbulence in blood flow caused by the closure of the valves, not from the contraction of the heart muscle
• The first heart sound (lubb) is created by blood turbulence associated with the closing of the atrioventricular valves soon after ventricular systole begins.
• The second heart sound (dupp) represents the closing of the semilunar valves close to the end of the ventricular systole.
https://www.youtube.com/watch?v=dBwr2GZCmQM
10. Heart Sounds
Where to listen on chest wall for heart sounds.
11. Stroke Volume and Heart Rate
Influences on Stroke Volume
• Preload (affect of stretching)
– more muscle is stretched, greater force of contraction
– more blood more force of contraction results
• Contractility
– autonomic nerves, hormones, Ca+2 or K+ levels
• Afterload
– amount of pressure created by the blood in the way
– high blood pressure creates high afterload
https://www.youtube.com/watch?v=vFRkSB46bl8
12. Regulation of Heart Rate
• Cardiac output depends on heart rate as well as stroke volume. Changing heart rate is the body’s principal mechanism of short-term control over cardiac output and blood pressure. Several factors contribute to regulation of heart rate.
• Nervous control from the cardiovascular center in the medulla
– Sympathetic impulses increase heart rate and force of contraction
– parasympathetic impulses decrease heart rate.
– Baroreceptors (pressure receptors) detect change in BP and send info to the cardiovascular center
• located in the arch of the aorta and carotid arteries
• Heart rate is also affected by hormones
– epinephrine, norepinephrine, thyroid hormones
– ions (Na+, K+, Ca2+)
– age, gender, physical fitness, and temperature
13. Autonomic regulation of the heart
• Nervous control of the cardiovascular system stems from the cardiovascular center in the medulla oblongata
• Proprioceptors, baroreceptors, and chemoreceptors monitor factors that influence the heart rate.
• Sympathetic impulses increase heart rate and force of contraction; parasympathetic impulses decrease heart rate.
14. Chemical regulation of heart rate
• Heart rate affected by hormones (epinephrine, norepinephrine, thyroid hormones).
• Cations (Na+, K+, Ca+2) also affect heart rate.
• Other factors such as age, gender, physical fitness, and temperature also affect heart rate.
SUMMARY:
https://www.youtube.com/watch?v=IS9TD9fHFv0
https://www.youtube.com/watch?v=x432O7VhfNU
_____
1. Structure and function of blood vessels
• Blood vessels form a closed system of tubes that carry blood away from the heart, transport it to the tissues of the body, and then return it to the heart.
– Arteries carry blood from the heart to the tissues.
– Arterioles are small arteries that connect to capillaries.
– Capillaries are the site of substance exchange between the blood and body tissues.
– Venules connect capillaries to larger veins.
– Veins convey blood from the tissues back to the heart.
– Vaso vasorum are small blood vessels that supply blood to the cells of the walls of the arteries and veins.
2. Arteries
• The wall of an artery consists of three major layers
– Tunica interna (intima)
– Tunica media
– Tunica externa
• Arteries carry blood away from the heart to the tissues.
• The functional properties of arteries are elasticity and contractility
3. Arterioles
• Arterioles are very small, almost microscopic, arteries that deliver blood to capillaries
• Through vasoconstriction (decrease in the size of the lumen of a blood vessel) and vasodilation (increase in the size of the lumen of a blood vessel), arterioles assume a key role in regulating blood flow from arteries into capillaries and in altering arterial blood pressure.
4. Capillaries form Microcirculation
• Microscopic vessels that connect arterioles to venules
• Found near every cell in the body but more extensive in highly active tissue (muscles, liver, kidneys & brain)
• Function is exchange of nutrients & wastes between blood and tissue fluid
• Capillary walls are composed of only a single layer of cells (endothelium) and a basement membrane
Venules
• Small veins collecting blood from capillaries
Veins
• Veins consist of the same three tunics as arteries but have a thinner tunica interna and media and a thicker tunica externa
• Still adaptable to variations in volume & pressure
• Valves are thin folds of tunica interna designed to prevent backflow
5. Capillary Exchange
• Movement of materials in & out of a capillary
– diffusion (most important method)
• Substances such as O2, CO2, glucose, amino acids, hormones, and others diffuse down their concentration gradients.
• all plasma solutes except large proteins pass freely across
– through lipid bilayer, fenestrations or intercellular clefts
– blood brain barrier does not allow diffusion of water-soluble materials
– transcytosis
• passage of material across endothelium in tiny vesicles by endocytosis and exocytosis
– large, lipid-insoluble molecules such as insulin or maternal antibodies passing through placental circulation to fetus
6. Dynamics of Capillary Exchange
• Starling’s law of the capillaries is that the volume of fluid & solutes reabsorbed is almost as large as the volume filtered
7. Shock and Homeostasis
• Shock is an inadequate cardiac output that results in failure of the cardiovascular system to deliver adequate amounts of oxygen and nutrients to meet the metabolic needs of body cells. As a result, cellular membranes dysfunction, cellular metabolism is abnormal, and cellular death may eventually occur without proper treatment.
– inadequate perfusion
– cells forced to switch to anaerobic respiration
– lactic acid builds up
– cells and tissues become damaged & die
8. Types of Shock
• Hypovolemic shock is due to decreased blood volume.
• Cardiogenic shock is due to poor heart function.
• Vascular shock is due to inappropriate vasodilation.
• Obstructive shock is due to obstruction of blood flow.
• Mechanisms of compensation in shock attempt to return cardiac output & BP to normal
– activation of renin-angiotensin-aldosterone
– secretion of antidiuretic hormone
– activation of sympathetic nervous system
– release of local vasodilators
9. Restoring BP during Hypovolemic Shock
10. Circulatory Routes
• Systemic circulation is left side heart to body & back to heart
• Hepatic Portal circulation is capillaries of GI tract to capillaries in liver
• Pulmonary circulation is right-side heart to lungs & back to heart
• Fetal circulation is from fetal heart through umbilical cord to placenta & back
• The systemic circulation takes oxygenated blood from the left ventricle through the aorta to all parts of the body, including some lung tissue (but does not supply the air sacs of the lungs) and returns the deoxygenated blood to the right atrium.
11. Arterial Branches of Systemic Circulation
• All are branches from aorta supplying arms, head, lower limbs and all viscera with O2 from the lungs
• Aorta arises from left ventricle (thickest chamber)
– 4 major divisions of aorta:ascending aorta,arch of aorta,thoracic aorta,abdominal aorta
12. Aorta and Its Superior Branches
• Aorta is largest artery of the body
– ascending aorta
• 2 coronary arteries supply myocardium
– arch of aorta -- branches to the arms & head
• brachiocephalic trunk branches into right common carotid and right subclavian
• left subclavian & left carotid arise independently
– thoracic aorta supplies branches to pericardium, esophagus, bronchi, diaphragm, intercostal & chest muscles, mammary gland, skin, vertebrae and spinal cord
13. Veins of the Systemic Circulation
• Drain blood from entire body & return it to right side of heart
• Deep veins parallel the arteries in the region
• Superficial veins are found just beneath the skin
• superior vena cava drains the head and upper extremities
• inferior vena cava drains the abdomen, pelvis & lower limbs
• coronary sinus is large vein draining the heart muscle back into the heart
14. Pulmonary Circulation
•The pulmonary circulation takes deoxygenated blood from the right ventricle to the air sacs of the lungs and returns oxygenated blood from the lungs to the left atrium
•Vessels include pulmonary trunk, arteries and veins
•Differences from systemic circulation
•pulmonary arteries. are larger, thinner with less elastic tissue
•resistance to is low & pulmonary blood pressure is reduced
15. Fetal Circulation
• Oxygen from placenta reaches heart via fetal veins in umbilical cord.
– bypasses liver
• Heart pumps oxygenated blood to capillaries in all fetal tissues including lungs.
• Umbilical aa. Branch off iliac aa. to return blood to placenta.
16. Aging and the Cardiovascular System
• General changes associated with aging
– decreased compliance of aorta
– reduction in cardiac muscle fiber size
– reduced cardiac output & maximum heart rate
– increase in systolic pressure
• Total cholesterol & LDL increases, HDL decreases
• Congestive heart failure, coronary artery disease and atherosclerosis more likely
SUMMARY:
https://www.youtube.com/watch?v=uAoFdseqTUs
https://www.youtube.com/watch?v=6ecmOuCIoNc
https://www.youtube.com/watch?v=IS9TD9fHFv0
https://www.youtube.com/watch?v=X3BCFOlk1oQ
https://www.youtube.com/watch?v=g68QzDBZmjE
https://www.youtube.com/watch?v=WueGqL58tlo
https://www.youtube.com/watch?v=bY6IWVgFCrQ
https://www.youtube.com/watch?v=_qmNCJxpsr0&t=10s
https://www.youtube.com/watch?v=SwHjwO7BnsI
L 21 Lymphatic System
1. The Lymphatic System
• The ability to ward off the pathogens that produce disease is called resistance.
• Immunity involves activation of specific lymphocytes that combat a particular pathogen or other foreign substance.
• Pathogens are infectious agents such as viruses, bacteria, fungi, and protozoa.
• The body system that carries out immune responses is the lymphatic system.
• Specific resistance or immunity is ability to fight a specific pathogen
– cell-mediated immunity
– antibody-mediated immunity
2. Lymphatic System
• Organs, vessels and a fluid called lymph
– similar to interstitial fluid
• Organs involved
– red bone marrow
– thymus
– spleen
– lymph nodes
– diffuse lymphatic tissue
• tonsils, adenoids & peyers patches
3. Functions of the Lymphatic System
• Draining excess interstitial fluid & plasma proteins from tissue spaces
• Transporting dietary lipids & vitamins from GI tract to the blood
• Facilitating immune responses
– recognize microbes or abnormal cells & responding by killing them directly or secreting antibodies that cause their destruction
4. Lymphatic Organs & Tissues
• Widely distributed throughout the body
• Primary lymphatic organs
– provide environment for stem cells to divide & mature into B and T lymphocytes
• red bone marrow gives rise to mature B cells
• thymus is site where pre-T cells from red marrow mature
• Secondary lymphatic organs & tissues
– site where most immune responses occur
• lymph nodes, spleen & lymphatic nodules
5. Thymus Gland
• 2 lobed organ located in mediastinum
6. Lymph Nodes
• Lymph nodes are encapsulated oval structures located along lymphatic vessels
• They contain T cells, macrophages, follicular dendritic cells, and B cells.
• Macrophages destroy some foreign substances by phagocytosis and lymphocytes bring about the destruction of others by immune responses.
7. Spleen
• Spleen the largest mass of lymphatic tissue in the body
• Macrophages remove worn-out or defective RBCs, WBCs, and platelets.
• The spleen stores blood platelets in the red pulp.
8. First Line of Defense: Skin and Mucous Membranes
• Nonspecific resistance refers to a wide variety of body responses against a wide range of pathogens (disease producing organisms) and their toxins.
• Mechanical protection includes the intact epidermis layer of the skin mucous membranes, the lacrimal apparatus, saliva, mucus, cilia, the epiglottis, and the flow of urine. Defecation and vomiting also may be considered mechanical processes that expel microbes.
• Chemical protection is localized on the skin, in loose connective tissue, stomach, and vagina.
• The skin produces sebum, which has a low pH due to the presence of unsaturated fatty acids and lactic acid.
• Lysozyme is an enzyme component of sweat that also has antimicrobial properties.
• Gastric juice renders the stomach nearly sterile because its low pH (kills many bacteria and destroys most of their toxins; vaginal secretions also are slightly acidic.
9. Second Line of Defense: Internal Defenses
• The second line of defense involves internal antimicrobial proteins, phagocytic and natural killer cells, inflammation, and fever
– Antimicrobial proteins discourage microbial growth
– NK cells kill a variety of microbes & tumor cells
– Phagocytes (neutrophils & macrophages)
– Inflammation Function is to trap microbes, toxins or foreign material & begin tissue repair
– Fever Benefits intensifies effects of interferons, inhibits bacterial growth, speeds up tissue repair
10. SPECIFIC RESISTANCE: IMMUNITY
• Immunity is the ability of the body to defend itself against specific invading agents.
• Differs from nonspecific defense mechanisms
– specificity----recognize self & non-self
– memory----2nd encounter produces even more vigorous response
• Antigens are substances recognized as foreign by the immune responses.
• The branch of science that deals with the responses of the body when challenged by antigens is called immunology.
11. Maturation of T and B Cells
• T cell mature in thymus
– cell-mediated response
• killer cells attack antigens
• helper cells costimulate T and B cells
– Thymus site where T cells become immunocompetent
– effective against fungi, viruses, parasites, cancer, and tissue transplants
• B cells in bone marrow
– antibody-mediated response
• plasma cells form antibodies
– effective against bacteria
– Plasma cells are differentiated clones of B cells that produce antibodies.
12. Antibody-Mediated Immunity
• The body contains not only millions of different T cells but also millions of different B cells, each capable of responding to a specific antigen.
• B cells sit still and let antigens be brought to them
– stay put in lymph nodes, spleen or peyer’s patches
• Once activated, differentiate into plasma cells that secrete antibodies
• Antibodies circulate in lymph and blood
– combines with epitope on antigen similarly to key fits a specific lock
13. Antibodies
• An antibody is a protein that can combine specifically with the antigenic determinant on the antigen that triggered its production.
• Antibody Actions
– Neutralization of antigen by blocking effects of toxins or preventing its attachment to body cells
– Immobilize bacteria by attacking cilia/flagella
– Agglutinate & precipitate antigens by cross-linking them causing clumping & precipitation
– Complement activation
– Enhancing phagocytosis through precipitation, complement activation or opsonization (coating with special substance)
14. Disease related lymphatic system
• AIDS is a condition in which a person experiences a telltale assortment of infections as a result of the progressive destruction of immune cells by the human immunodeficiency virus (HIV).
• A person who is overly reactive to a substance that is tolerated by most others is said to be hypersensitive (allergic). Whenever an allergic reaction occurs, there is tissue injury. The antigens that induce an allergic reaction are called allergens.
• In an autoimmune disease the immune system fails to display self-tolerance and attacks the person’s own tissue.
• Infectious mononucleosis is a contagious disease primarily affecting lymphatic tissue throughout the body but also affecting the blood. It is caused by the Epstein-Barr virus which multiplies in B cells. There is no cure, and treatment consists of watching for and treating complications. Usually the disease runs its course in a few weeks.
• Lymphomas are cancers of the lymphatic organs especially the lymph nodes. The two main types are: Hodgkin disease and non-Hodgkin lymphoma.
• Systemic lupus erythematosus is a chronic autoimmune, inflammatory disease that affects multiple body systems.
SUMMARY:
https://www.youtube.com/watch?v=o0-1OknbO3M
https://www.youtube.com/watch?v=cCPyWFK0IKs&t=16s
https://www.youtube.com/watch?v=dVN4cGLzfDQ
https://www.youtube.com/watch?v=zQGOcOUBi6s
https://www.youtube.com/watch?v=gYJnZGExlws
https://www.youtube.com/watch?v=_VhcZTGv0CU
https://www.youtube.com/watch?v=KhVC3E_UH7I
https://www.youtube.com/watch?v=Z5DTL72CClM
https://www.youtube.com/watch?v=nqRn5fN22t4
L22 The Respiratory System
1. Introduction
• The two systems that cooperate to supply O2 and eliminate CO2 are the cardiovascular and the respiratory system.
• The respiratory system provides for gas exchange.
• The cardiovascular system transports the respiratory gases.
• Failure of either system has the same effect on the body: disruption of homeostasis and rapid death of cells from oxygen starvation and buildup of waste products.
• Respiration is the exchange of gases between the atmosphere, blood, and cells. It takes place in three basic steps: ventilation (breathing), external (pulmonary) respiration, and internal (tissue) respiration.
2. The Respiratory System
• Nose
• Pharynx = throat
• Larynx = voicebox
• Trachea = windpipe
• Bronchi = airways
• Lungs
• Locations of infections
– upper respiratory tract is above vocal cords
– lower respiratory tract is below vocal cords
• The conducting system consists of a series of cavities and tubes - nose, pharynx, larynx, trachea, bronchi, bronchiole, and terminal bronchioles - that conduct air into the lungs. The respiratory portion consists of the area where gas exchange occurs -respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.
3. Structures Nose
• Large chamber within the skull
• Internal nares (choanae) are openings to pharynx
• Olfactory epithelium for sense of smell
• Pseudostratified ciliated columnar with goblet cells lines nasal cavity
• Paranasal sinuses open into nasal cavity
4. Pharynx
•The pharynx (throat) is a muscular tube lined by a mucous membrane
•The anatomic regions are the nasopharynx, oropharynx, and laryngopharynx.
•The nasopharynx functions in respiration.
•Both the oropharynx and laryngopharynx function in digestion and in respiration (serving as a passageway for both air and food).
• Functions
– passageway for food and air
– resonating chamber for speech production
• Nasopharynx
– openings of auditory (Eustachian) tubes from middle ear cavity
– Passageway for air only
• Oropharynx
– From soft palate to epiglottis
– fauces is opening from mouth into oropharynx
– palatine tonsils found in side walls, lingual tonsil in tongue
– Common passageway for food & air
• Laryngopharynx
– Extends from epiglottis to cricoid cartilage
– Common passageway for food & air & ends as esophagus inferiorly
5. Larynx
• The larynx (voice box) is a passageway that connects the pharynx with the trachea. The primary site of voice production.
• It contains the thyroid cartilage (Adam’s apple)
• The epiglottis, which prevents food from entering the larynx;
• Normally receives only air.
• Lies anterior to the esophagus.
6. Trachea and Bronchial Tree
•The trachea (windpipe) extends from the larynx to the primary bronchi
•It is composed of smooth muscle and C-shaped rings of cartilage and is lined with pseudostratified ciliated columnar epithelium.
•The cartilage rings keep the airway open.
7. Bronchi and Bronchioles
• The trachea divides into the right and left pulmonary bronchi
• Primary bronchi supply each lung
• Secondary bronchi supply each lobe of the lungs (3 right + 2 left)
• Tertiary bronchi supply each bronchopulmonary segment
• Repeated branchings called bronchioles form a bronchial tree
• Walls of bronchi contain rings of cartilage.
• Walls of bronchioles contain smooth muscle.
8. Lungs
• Oblique & horizontal fissure in right lung results in 3 lobes
• Oblique fissure only in left lung produces 2 lobes
• Lungs are paired organs in the thoracic cavity
• The pleural cavities may fill with air (pneumothorax) or blood (hemothorax).
• The pleurae are the serous membranes that cover the lungs.
9. Alveoli
• Branchings of single arteriole, venule & bronchiole are wrapped by elastic CT
• Alveolar ducts surrounded by alveolar sacs & alveoli
– sac is 2 or more alveoli sharing a common opening
• Gas exchange occurs across the alveolar-capillary membrane
10. Pulmonary ventilation
• Respiration occurs in three basic steps: pulmonary ventilation, external respiration, and internal respiration.
• Inspiration (inhalation) is the process of bringing air into the lungs.
• Air moves into lungs when pressure inside lungs is less than atmospheric pressure
• Air moves out of the lungs when pressure inside lungs is greater than atmospheric pressure
• Directly factor in the rate of gas exchange
– difference in the partial pressures of a gas
– solubility of a gas
– size (molecular weight) of a gas
– diffusion distance
11. Inspiration
• The first step in expanding the lungs involves contraction of the main inspiratory muscle, the diaphragm (Figure 23.14).
• Inhalation occurs when alveolar (intrapulmonic) pressure falls below atmospheric pressure. Contraction of the diaphragm and external intercostal muscles increases the size of the thorax, thus decreasing the intrapleural (intrathoracic) pressure so that the lungs expand. Expansion of the lungs decreases alveolar pressure so that air moves along the pressure gradient from the atmosphere into the lungs.
• During forced inhalation, accessory muscles of inspiration (sternocleidomastoids, scalenes, and pectoralis minor) are also used.
• A summary of inhalation is presented in Figure 23.16a.
12. Expiration
• Expiration (exhalation) is the movement of air out of the lungs.
• Exhalation occurs when alveolar pressure is higher than atmospheric pressure.
• Exhalation becomes active during labored breathing and when air movement out of the lungs is impeded. Forced expiration employs contraction of the internal intercostals and abdominal muscles
13. Summary of Breathing
• Alveolar pressure decreases & air rushes in
• Alveolar pressure increases & air rushes out
14. External Respiration
• O2 and CO2 diffuse from areas of their higher partial pressures to areas of their lower partial pressures Diffusion depends on partial pressure differences
• Compare gas movements in pulmonary capillaries to tissue capillaries
15. Internal Respiration
• Exchange of gases between blood & tissues
• Conversion of oxygenated blood into deoxygenated
• Observe diffusion of O2 inward
– at rest 25% of available O2 enters cells
– during exercise more O2 is absorbed
• Observe diffusion of CO2 outward
16. Oxygen Transport
• In each 100 ml of oxygenated blood, 1.5% of the O2 is dissolved in the plasma and 98.5% is carried with hemoglobin (Hb) inside red blood cells as oxyhemglobin (HbO2) \
• Hemoglobin consists of a protein portion called globin and a pigment called heme.
• The heme portion contains 4 atoms of iron, each capable of combining with a molecule of oxygen.
17. Carbon Dioxide Transport
• 100 ml of blood carries 55 ml of CO2
• Is carried by the blood in 3 ways
– dissolved in plasma
– combined with the globin part of Hb molecule forming carbaminohemoglobin
– as part of bicarbonate ion
• CO2 + H2O combine to form carbonic acid that dissociates into H+ and bicarbonate ion
18. Summary of Gas Exchange & Transport
19. Role of the Respiratory Center
• Respiratory mm. controlled by neurons in pons & medulla
• 3 groups of neurons
– medullary rhythmicity
• Controls basic rhythm of respiration
– Pneumotaxic
• helps coordinate the transition between inspiration and expiration
– apneustic centers
• sends impulses to the inspiratory area that activate it and prolong inspiration, inhibiting expiration.
20. Negative Feedback Regulation of Breathing
• Negative feedback control of breathing
• Increase in arterial pCO2 (partial pressure)
• Stimulates receptors
• Inspiratory center
• Muscles of respiration contract more frequently & forcefully
• pCO2 Decreases
20. Aging & the Respiratory System
• Respiratory tissues & chest wall become more rigid
• Vital capacity decreases to 35% by age 70.
• Decreases in macrophage activity
• Diminished ciliary action
• Decrease in blood levels of O2
• Result is an age-related susceptibility to pneumonia or bronchitis
SUMMARY:
https://www.youtube.com/watch?v=03qvN5pjCTU
https://www.youtube.com/watch?v=kacMYexDgHg
https://www.youtube.com/watch?v=wc2K1Olt4Q8
https://www.youtube.com/watch?v=6qnSsV2syUE
https://www.youtube.com/watch?v=PLFq-1h4870
https://www.youtube.com/watch?v=GjfD55C9v38
https://www.youtube.com/watch?v=KITa-HNpJgU
https://www.youtube.com/watch?v=iUuNtfdJDTY
L23 The Digestive System
1. The Digestive System
• Structure
– Gross Anatomy
– Histology
• The medical professions that study the structures, functions, and disorders of the digestive tract are gastroenterology for the upper end of the system and proctology for the lower end.
2. Overview of GI tract Functions
• Mouth---bite, chew, swallow
• Pharynx and esophagus----transport
• Stomach----mechanical disruption; absorption of water & alcohol
• Small intestine--chemical & mechanical digestion & absorption
• Large intestine----absorb electrolytes & vitamins (B and K)
• Rectum and anus---defecation
3. Organization
• The two major sections of the digestive system perform the processes required to prepare food for use in the body
• The gastrointestinal tract is the tube open at both ends for the transit of food during processing. The functional segments of the GI tract include the mouth, esophagus, stomach, small intestine, and large intestine.
• The accessory structures that contribute to the food processing include the teeth, tongue, salivary glands, liver, gallbladder, and pancreas.
4. Digestion
• Digestion includes six basic processes.
• Ingestion is taking food into the mouth (eating).
• Secretion is the release, by cells within the walls of the GI tract and accessory organs, of water, acid, buffers, and enzymes into the lumen of the tract.
• Mixing and propulsion result from the alternating contraction and relaxation of the smooth muscles within the walls of the GI tract.
• Digestion
• Mechanical digestion consists of movements of the GI tract that aid chemical digestion.
• Chemical digestion is a series of catabolic (hydrolysis) reactions that break down large carbohydrate, lipid, and protein food molecules into smaller molecules that are usable by body cells.
• Absorption is the passage of end products of digestion from the GI tract into blood or lymph for distribution to cells.
• Defecation is emptying of the rectum, eliminating indigestible substances from the GI tract.
5. Layers of the GI Tract
A. Mucosal layer
B. Submucosal layer
C. Muscularis layer
D. Serosa layer
6. Peritoneum
• Peritoneum
– visceral layer covers organs
– parietal layer lines the walls of body cavity
• Peritoneal cavity
– potential space containing a bit of serous fluid
7. Mouth
• The mouth (oral or buccal cavity) is formed by the cheeks, hard and soft palate, lips, and tongue
• The oral cavity proper is a space that extends from the gums and teeth to the fauces, the opening between the oral cavity and the pharynx or throat.
8. Salivary Glands
• Parotid below your ear and over the masseter
• Submandibular is under lower edge of mandible
• Sublingual is deep to the tongue in floor of mouth
• Saliva lubricates and dissolves food and starts the chemical digestion of carbohydrates in the mouth. It also functions to keep the mucous membranes of the mouth and throat moist.
• Saliva rich in amylase comes primarily from the parotid and submandibular glands, helps moisten food so that it can be swallowed and contains primarily water.
9. Structure and Function of the Tongue
• The tongue, together with its associated muscle, forms the floor of the oral cavity. It is composed of skeletal muscle covered with mucous membrane.
10. Tooth
• The teeth project into the mouth and are adapted for mechanical digestion
• A typical tooth consists of three principal portions: crown, root, and neck.
• Teeth are composed primarily of dentin, a calcified connective tissue that gives the tooth its basic shape and rigidity; the dentin of the crown is covered by enamel, the hardest substance in the body, which protects the tooth from the wear of chewing.
11. Pharynx
• Funnel-shaped tube extending from internal nares to the esophagus (posteriorly) and larynx (anteriorly)
• Deglutition or swallowing is facilitated by saliva and mucus
– sensory nerves send signals to deglutition center in brainstem
– soft palate is lifted to close nasopharynx
– larynx is lifted as epiglottis is bent to cover glottis
12. Esophagus
• In front of vertebrae
• Posterior/behind to trachea
• Posterior to the heart
• The role of the esophagus is to secrete mucus and transport food to the stomach.
13. Anatomy of Stomach
• The stomach is a J-shaped enlargement of the GI tract that begins at the bottom of the esophagus and ends at the pyloric sphincter
• It serves as a mixing and holding area for food, begins the digestion of proteins, and continues the digestion of triglycerides, converting a bolus to a liquid called chyme. It can also absorb some substances.
• delivers chyme to the duodenum
• receives the bolus from esophagus
• performs both mechanical and chemical digestive processes
• produces HCl, pepsinogen and gastric lipase
14. Anatomy of the Pancreas
• Pancreatic islets (islets of Langerhans) secrete hormones and acini secrete a mixture of fluid and digestive enzymes called pancreatic juice
• The pancreas is divided into a head, body, and tail and is connected to the duodenum via the pancreatic duct (duct of Wirsung) and accessory duct (duct of Santorini)
15. Anatomy of the Liver and Gallbladder
• The liver is the heaviest gland in the body and the second largest organ in the body after the skin.
• Liver
– below diaphragm
– right lobe larger
– gallbladder on right lobe
• Gallbladder
– fundus, body & neck
16. Pathway of Bile Secretion
• Hepatic cells (hepatocytes) produce bile that is transported by a duct system to the gallbladder for concentration and temporary storage.
• Bile is partially an excretory product (containing components of worn-out red blood cells) and partially a digestive secretion.
• Bile’s contribution to digestion is the emulsification of triglycerides
• The liver also functions in carbohydrate, lipid, and protein metabolism; removal of drugs and hormones from the blood; excretion of bilirubin; synthesis of bile salts; storage of vitamins and minerals; phagocytosis; and activation of vitamin D.
17. Anatomy of the Small Intestine
• The major events of digestion and absorption occur in the small intestine.
• The small intestine extends from the pyloric sphincter to the ileocecal sphincter.
• Is the major site of digestion and absorption.
• Consists of the duodenum, jejunum and ileum.
• Has villi and microvilli that increase its surface area for absorption.
• Contains circular folds that increase surface area and absorption.
18. Review: Digestion of Proteins
• Stomach
– HCl denatures or unfolds proteins
– pepsin turns proteins into peptides
• Pancreas
– digestive enzymes---split peptide bonds between different amino acids
– brush border enzymes-----aminopeptidase or dipeptidase
– enzymes split dipeptides to amino acids (dipeptidase)
19. Review: Digestion of Lipids
• Mouth----lingual lipase
• Most lipid digestion, in an adult, occurs in the small intestine.
– emulsification by bile of globules of triglycerides
– pancreatic lipase---splits triglycerides into fatty acids & monoglycerides
– no enzymes in brush border
20. Digestion of Nucleic Acids
• Nucleic acids are broken down into nucleotides for absorption.
• Nucleotides produced are further digested by brush border enzymes (nucleosidease and phosphatase)
– pentose, phosphate & nitrogenous bases
• Absorbed by active transport
21. Anatomy of Large Intestine
• The large intestine (colon) extends from the ileocecal sphincter to the anus.
• Its subdivisions include the cecum, colon, rectum, and anal canal
• Ascending & descending colon are retroperitoneal
• Absorb electrolytes & vitamins (B and K)
• Anal canal
– internal sphincter----smooth muscle & involuntary
– external sphincter----skeletal muscle & voluntary control
22. Aging and the Digestive System
• Changes that occur
– decreased secretory mechanisms
– decreased motility
– loss of strength & tone of muscular tissue
– changes in neurosensory feedback
– diminished response to pain & internal stimuli
• Symptoms
– sores, loss of taste, peridontal disease, difficulty swallowing, hernia, gastritis, ulcers, malabsorption, jaundice, cirrhosis, pancreatitis, hemorrhoids and constipation
• Cancer of the colon or rectum is common
SUMMARY:
https://www.youtube.com/watch?v=zSXgoYdHotw
https://www.youtube.com/watch?v=YQm5RCz9Pxc
https://www.youtube.com/watch?v=Og5xAdC8EUI
L24 The Urinary System
1. The Urinary System
• The urinary system consists of two kidneys, two ureters, one urinary bladder, and one urethra
• Urine is excreted from each kidney through its ureter and is stored in the urinary bladder until it is expelled from the body through the urethra.
• The specialized branch of medicine that deals with structure, function, and diseases of the male and female urinary systems and the male reproductive system is known as nephrology. The branch of surgery related to male and female urinary systems and the male reproductive system is called urology.
2. Overview of Kidney Functions
• Regulation of blood ionic composition
– Na+, K+, Ca+2, Cl- and phosphate ions
• Regulation of blood pH, osmolarity & glucose
• Regulation of blood volume
– conserving or eliminating water
• Regulation of blood pressure
– secreting the enzyme renin
– adjusting renal resistance
• Release of erythropoietin & calcitriol
• Excretion of wastes & foreign substances
3. Anatomy and Histology of the Kidneys
• The paired kidneys are retroperitoneal organs
• Paired kidney-bean-shaped organ
• Found just above the waist between the peritoneum & posterior wall of abdomen
4. Internal Anatomy of Kidney
• Internally, the kidneys consist of cortex, medulla, pyramids, papillae, columns, calyces, and pelves
• The nephron is the functional unit of the kidney.
• Functions of different capillary beds
– glomerular capillaries where filtration of blood occurs
– peritubular capillaries that carry away reabsorbed substances from filtrate
– vasa recta supplies nutrients to medulla without disrupting its osmolarity form
5. The Nephron
• Glomerular capillaries are formed between the afferent & efferent arterioles
• A nephron consists of a renal corpuscle where fluid is filtered, and a renal tubule into which the filtered fluid passes
• Nephrons perform three basic functions: glomerular filtration, tubular reabsorption, and tubular secretion.
• A renal tubule consists of a proximal convoluted tubule (PCT), loop of Henle (nephron loop), and distal convoluted tubule (DCT).
6. Structure of Renal Corpuscle
• Bowman’s capsule surrounds capsular space
– Podocytes(modified simple squamous epithelial cells) cover capillaries to form visceral layer
– simple squamous cells form parietal layer of capsule
• Glomerular capillaries arise from afferent arteriole & form a ball before emptying into efferent arteriole
7. Overview of Renal Physiology
• Nephrons and collecting ducts perform three basic processes while producing urine: glomerular filtration, tubular secretion, and tubular reabsorption
8. Filtration Membrane
• #1 Stops all cells and platelets
• #2 Stops large plasma proteins
9. Transport Mechanisms
• Solute reabsorption drives water reabsorption. The mechanisms that accomplish Na+ reabsorption in each portion of the renal tubule and collecting duct recover not only filtered Na+ but also other electrolytes, nutrients, and water.
• Water is only reabsorbed by osmosis
• Transport across membranes can be either active or passive
10. Reabsorption and Secretion in the Proximal Convoluted Tubule
• The majority of solute and water reabsorption from filtered fluid occurs in the proximal convoluted tubules and most absorptive processes involve Na+.
• Proximal convoluted tubule Na+ transporters promote reabsorption of 100% of most organic solutes, such as glucose and amino acids; 80-90% of bicarbonate ions; 65% of water, Na+, and K+; 50% of Cl-; and a variable amount of Ca+2, Mg+2, and HPO4-2.
• Normally, 100% of filtered glucose, amino acids, lactic acid, water-soluble vitamins, and other nutrients are reabsorbed
• Urea and ammonia in the blood are both filtered at the glomerulus and secreted by the proximal convoluted tubule cells into the tubules.
11. Reabsorption in the Loop of Henle
• The loop of Henle sets the stage for independent regulation of both the volume and osmolarity of body fluids.
• Although about 15% of the filtered water is reabsorbed in the descending limb, little or no water is reabsorbed in the ascending limb.
12. Production of Dilute and Concentrated Urine
• The rate at which water is lost from the body depends mainly on ADH, which controls water permeability of principal cells in the collecting duct (and in the last portion of the distal convoluted tubule).
• When ADH level is very low, the kidneys produce dilute urine and excrete excess water; in other words, renal tubules absorb more solutes than water
13. Urine Storage, Transportation, and Elimination
• Urine drains through papillary ducts into minor calyces, which joint to become major calyces that unite to form the renal pelvis. From the renal pelvis, urine drains into the ureters and then into the urinary bladder, and finally, out of the body by way of the urethra.
14. Ureters
• Each of the two ureters connects the renal pelvis of one kidney to the urinary bladder.
• The ureters transport urine from the renal pelvis to the urinary bladder, primarily by peristalsis, but hydrostatic pressure and gravity also contribute
• Extends from renal pelvis to bladder
15. Urinary Bladder
• The urinary bladder is a hollow muscular organ situated in the pelvic cavity posterior to the pubic symphysis.
• In the floor of the urinary bladder is a small, smooth triangular area, the trigone. The ureters enter the urinary bladder near two posterior points in the triangle; the urethra drains the urinary bladder from the anterior point of the triangle
• Posterior to pubic symphysis
• In females is anterior to vagina & inferior to uterus
• In males lies anterior to rectum
16. Urethra
• Males
– tube passes through prostate, UG diaphragm & penis
• Females
– orifice between clitoris & vagina
17. Aging and the Urinary System
• After age 40, the effectiveness of kidney function begins to decrease.
• Anatomical changes
– kidneys shrink in size from 260 g to 200 g
• Functional changes
– lowered blood flow & filter less blood (50%)
– diminished sensation of thirst increases susceptibility to dehydration
• Diseases common with age
– acute and chronic inflammations & canaliculi
– infections, nocturia, polyuria, dysuria, retention or incontinence and hematuria
• Cancer of prostate is common in elderly men
SUMMARY:
https://www.youtube.com/watch?v=iKusxCtH62c
https://www.youtube.com/watch?v=82mW8bpcSyU
https://www.youtube.com/watch?v=9_h0ZXx1lFw
https://www.youtube.com/watch?v=1NtPjzm1-74
L25 Fluid, Electrolyte and Acid-Base Homeostasis
1. Fluid, Electrolyte and Acid-Base Homeostasis
•Body fluid
–all the water and dissolved solutes in the body’s fluid compartments
•Mechanisms regulate
–total volume
–distribution
–concentration of solutes and pH
•Water is the main component of all body fluids.
•About two-thirds of the body’s fluid is located in cells and is called intracellular fluid (ICF).
•The other third is called extracellular fluid (ECF).
2. Introduction
•Selectively permeable membranes separate body fluids into distinct compartments.
–Plasma membranes of individual cells separate intracellular fluid from interstitial fluid.
–Blood vessel walls divide interstitial fluid from blood plasma.
•Osmosis is the primary way in which water moves in and out of body compartments. The concentrations of solutes in the fluids is therefore a major determinant of fluid balance.
•Most solutes in body fluids are electrolytes, compounds that dissociate into ions.
3. Body Water Gain and Loss
•Gain from ingestion and metabolic water formed during aerobic respiration & dehydration synthesis reactions
•Normally loss = gain
–urine, feces, sweat, breathe
•A fluid imbalance between the intracellular and interstitial fluids can be caused by a change in their osmolarity.
•Most often a change in osmolarity is due to a change in the concentration of Na+.
4. Hormone Regulation of Water Balance
•Antidiuretic hormone (ADH) from the posterior pituitary
–stimulates thirst
–increases permeability of principal cells of collecting ducts to assist in water reabsorption
–very concentrated urine is formed
•ADH secretion shuts off after the intake of water
•ADH secretion is increased
–large decrease in blood volume
–severe dehydration and drop in blood pressure
–vomiting, diarrhea, heavy sweating or burns
5. Electrolytes in body fluids
•Electrolytes serve four general functions in the body.
–Because they are more numerous than nonelectrolytes, electrolytes control the osmosis of water between body compartments.
–maintain the acid-base balance required for normal cellular activities.
–carry electrical current, which allows production of action potentials and graded potentials and controls secretion of some hormones and neurotransmitters. Electrical currents are also important during development.
–cofactors needed for optimal activity of enzymes.
•Sodium(Na+) is the most abundant cation in plasma and interstitial fluid.
–Average daily intake exceeds normal requirements
–aldosterone causes increased reabsorption Na+
–ADH release ceases if Na+ levels too low--dilute urine lost until Na+ levels rise
–ANP increases Na+ and water excretion if Na+ levels too high
•Potassium(K+) is the most abundant cation in intracellular fluid.
–It is involved in maintaining fluid volume, impulse conduction, muscle contraction.
–Exchanged for H+ to help regulate pH in intracellular fluid
–The plasma level of K+is under the control of mineralocorticoids, mainly aldosterone.
•Calcium(Ca2+), the most abundant ion in the body, is principally an extracellular ion.
–It is a structural component of bones and teeth.
–Important role in blood clotting, neurotransmitter release, muscle tone & nerve and muscle function
–Regulated by parathyroid hormone
•Chloride(Cl-) is the major extracellular anion.
–Helps balance anions in different compartments
–passively follows Na+ so it is regulated indirectly by aldosterone levels
–ADH helps regulate Cl-in body fluids because it controls water loss in urine
–It plays a role in forming HCl in the stomach.
•Bicarbonate(HCO3 -) is a prominent ion in the plasma
–It is a significant plasma anion in electrolyte balance.
–It is a major component of the plasma acid-base buffer system.
–Kidneys are main regulator of plasma levels
•Magnesium (Mg2+) is primarily an intracellular cation.
–It activates several enzyme systems involved in the metabolism of carbohydrates and proteins and is needed for operation of the sodium pump.
–It is also important in neuromuscular activity, neural transmission within the central nervous system, and myocardial functioning.
6. Acid-Base Balance
•The overall acid-base balance of the body is maintained by controlling the H+concentration of body fluids, especially extracellular fluid.
•3 major mechanisms to regulate pH
–buffer system
–exhalation of CO2(respiratory system)
–kidney excretion of H+ (urinary system)
7. Buffer systems
•3 principal buffer systems
–protein buffer system
•Abundant in intracellular fluids & in plasma
–hemoglobin very good at buffering H+ in RBCs
–albumin is main plasma protein buffer
–carbonic acid-bicarbonate buffer system
•bicarbonate ion (HCO3-) can act as a weak base
•carbonic acid (H2CO3) can act as weak acid
–phosphate buffer system
•Most important intracellularly, but also acts to buffer acids in the urine
•Dihydrogen phosphate ion acts as a weak acid that can buffer a strong base
8. Exhalation of Carbon Dioxide
•The pH of body fluids may be adjusted by a change in the rate and depth of respirations,
•An increase in the rate and depth of breathing causes more carbon dioxide to be exhaled, thereby increasing pH.
•A decrease in respiration rate and depth means that less carbon dioxide is exhaled, causing the blood pH to fall.
•The pH of body fluids, in turn, affects the rate of breathing
•The kidneys excrete H+and reabsorb HCO3-to aid in maintaining pH.
•Respiratory centers inhibited or stimulated by changes is pH
9. Regulation of Acid-Base Balance
•Cells in the PCT and collecting ducts secrete hydrogen ions into the tubular fluid.
•These two types of cells help maintain body fluid pH by excreting excess H+ when pH is too low or by excreting excess HCO3–when the pH is too high.
•Respiratory Acidosis
–Cause is elevation/rising of pCO2 of blood
–Due to lack of removal of CO2 from blood
•emphysema, pulmonary edema, injury to the brainstem & respiratory centers
•Respiratory Alkalosis
–Arterial blood pCO2 is too low
–Hyperventilation caused by high altitude, pulmonary disease, stroke, anxiety, aspirin overdose
–Renal compensation involves decrease in excretion of H+ and increase reabsorption of bicarbonate
•Metabolic Acidosis
–Blood bicarbonate ion concentration too low
•loss of ion through diarrhea or kidney dysfunction
•accumulation of acid (ketosis with dieting/diabetes)
•kidney failing to remove H+ from protein metabolism
–Respiratory compensation by hyperventilation
•Metabolic Alkalosis
–Blood bicarbonate levels are too high
•Metabolic Alkalosis
–Blood bicarbonate levels are too high
–Cause is nonrespiratory loss of acid
•vomiting, gastric suctioning, use of diuretics, dehydration, excessive intake of alkaline drugs
–Respiratory compensation is hypoventilation
10. Impaired Homeostasis in the Elderly
•Decreased volume of intracellular fluid
–inadequate fluid intake
•Decreased total body K+ due to loss of muscle tissue or potassium-depleting diuretics for treatment of hypertension or heart disease
•Decreased respiratory & renal function
–slowing of exhalation of CO2
–decreased blood flow & glomerular filtration rate
–reduced sensitivity to ADH & impaired ability to produce dilute urine
–renal tubule cells produce less ammonia to combine with H+ and excrete as NH+4 (ammonium)
SUMMARY:
https://www.youtube.com/watch?v=eQIVK47wJus
https://www.youtube.com/watch?v=0wg9v9atAl8
https://www.youtube.com/watch?v=VzEEs00v-JU
https://www.youtube.com/watch?v=y06GEXOgmDg
https://www.youtube.com/watch?v=jW2-Xqg8lhw
https://www.youtube.com/watch?v=6598CguLEoU
https://www.youtube.com/watch?v=SdgM2biCaO0
L26 Reproductive System
1. The Reproductive Systems
•Gynecology is the specialized branch of medicine concerned with the diagnosis and treatment of diseases of the female reproductive system. Urologyis the study of the urinary system but also includes diagnosis and treatment of diseases and disorders of the male reproductive system.
•Gonads produce gametes & secrete sex hormones
•Reproductive systems
–gonads, ducts, glands & supporting structures
–Gynecology is study of female reproductive system
–Urology is study of urinary system & male reproductive system
2. Male Reproductive System
•The male structures of reproduction include the testes, a system of ducts (ductus epididymis, ductus deferens, ejaculatory duct, urethra), accessory sexglands(seminal vesicles, prostate gland, bulbourethral glands), and several supporting structures, including the penis
•Semen contains sperm plus glandular secretions
3. Scrotum
•The scrotumis a cutaneous outpouching of the abdomen that supports the testes; internally, a vertical septum divides it into two sacs, each containing a single testis
•Skin contains dartos muscle causes wrinkling
•Temperature regulation of testes
4. Testes
•The testes, or testicles, are paired oval-shaped glands (gonads) in the scrotum
•The testes contain seminiferous tubules(in which sperm cells are made)
•Embedded among the spermatogenic cellsin the tubules are large Sertoli cellsor sustentacular cells
•The Leydig cellsfound in the spaces between adjacent seminiferous tubules secrete testosterone
5. Spermatogenesis
•Spermatogenesis is formation of sperm cells from spermatogonia.
•The diploid primary spermatocytesundergo meiosis I forming haploid secondary spermatocytes.
•Seminiferous tubules contain all stages of sperm development: spermatogonia, primary spermatocyte, secondary spermatocyte, spermatid, spermatozoa, and supporting cells called sertoli cells
•They are produced at the rate of about 300 million Sperm per day and, once ejaculated, have a life expectancy of 48 hours within the female reproductive tract.
6. Hormonal Control of the Male reproductive
•GnRH (gonadotropin releasing hormone) stimulates anterior pituitary secretion of follicle-stimulating hormone(FSH) and luteinizing hormone(LH).
–LH assists spermatogenesis and stimulates production of testosterone.
–FSH initiates spermatogenesis
•Testosterone
–controls the growth, development, functioning, and maintenance of sex organs
–stimulates bone growth, protein anabolism, and sperm maturation
–stimulates development of male secondary sex characteristics.
–Negative feedback systems regulate testosterone production
•Inhibinis produced by sustentacular (Sertoli) cells. Inhibition of FSH by inhibin helps to regulate the rate of spermatogenesis.
7. Anatomy
•The ductus (vas) deferens, or seminal duct, stores sperm and propels them toward the urethra during ejaculation
•The ductus epididymis is the site of sperm maturation and storage
•The spermatic cordis a supporting structure of the male reproductive system.
•The ejaculatory ductsare formed by the union of the ducts from the seminal vesicles and ducti deferens; their function is to eject spermatozoa into the prostatic urethra
•The penis contains the urethra and is a passageway for the ejaculation of semen and urine
8. Accessory Sex Glands
•The seminal vesicles secrete an alkaline, viscous fluid that contains fructose, prostaglandins, and clotting proteins
The prostate gland secretes a milky, slightly acidic fluid that contains: citric acid, acid phosphatase and several proteolytic enzymes
The bulbourethral (Cowper’s) glands produce mucus for lubrication and an alkaline substance that neutralizes acid
9. Semen Statistics
•Mixture of sperm & seminal fluid
–slightly alkaline, milky appearance, sticky
•Normal sperm count is 50 to 150 million/ml
•A man is probably infertile if his sperm contains less than 20 million sperm/mL.
•It contains sperm and seminal fluids.
•It contains an antibiotic called seminal plasmin.
•It provides sperm with a transportation medium and nutrients.
10. Female Reproductive System
•The female organs of reproduction include the ovaries (gonads), uterine (Fallopian) tubes, uterus, vagina, vulva, and mammary glands
•Ovaries produce 2nd oocytes & hormones
•Uterine tubes transport fertilized ova
•Uterus where fetal development occurs
•Vagina & external genitalia constitute the vulva
•Mammary glands produce milk
11. Ovary
•They are the female gonads.
•They produce gametes called secondary oocytes.
•They produce estrogens and progesterone.
•They are homologous to the testes.
•Have a corpus luteumcontains the remnants of an ovulated follicle and produces progesterone, estrogens, relaxin, and inhibin until it degenerates into a corpus albicans.
•Oogenesisoccurs in the ovaries. It results in the formation of a single haploid secondary oocyte.
•Follicular Stages in ovary: primordial,primary,secondary,graafian and ovulation
12. Uterine or Fallopian Tubes
•tube extends from ovary to uterus
•The uterine(Fallopian) tubestransport ova from the ovaries to the uterus and are the normal sites of fertilization
13. Anatomy of the Uterus
•The uterus (womb) is an organ the size and shape of an inverted pear .
•Anatomical subdivisions :fundus,body,isthmus and cervix
•It serves as part of the pathway for sperm.
•It is the site of implantation of a fertilized ovum.
•It is the site development of the fetus during pregnancy.
•It is involved in labor.
•It is the source of menstrual flow.
14., Cervix, vagina and vulva
•Secretory cells of the mucosa of the cervix produce a cervical mucus
•Both the cervix and the mucus serve as a sperm reservoir, protect sperm from the hostile environment of the vagina, and protect sperm from phagocytes.
•The vagina functions as a passageway for spermatozoa and the menstrual flow, the receptacle of the penis during sexual intercourse, and the lower portion of the birth canal
•Vagina lies between urinary bladder and rectum
15. Vulva (pudendum)
•The term vulva, or pudendum, refers to the external genitalia of the female
•Mons pubis --fatty pad over the pubic symphysis
•Labia majora & minora --folds of skin encircling vestibule where find urethral and vaginal openings
•Clitoris --small mass of erectile tissue
•Bulb of vestibule --masses of erectile tissue just deep to the labia on either side of the vaginal orifice
16. Perineum
•The perineum is the diamond-shaped area between the thighs and buttocks of both males and females that contains the external genitals and anus
17. Mammary glands
•The mammary glands are modified sudoriferous (sweat) glands that lie over the pectoralis major and serratus anterior muscles
•The essential functions of the mammary glands are synthesis of milk, secretion and ejection of milk, which constitute lactation.
18. Female Reproductive Cycle -Introduction
•Ovarian cycle
–changes in ovary during & after maturation of oocyte
•The uterine(menstrual) cycle
–involves changes in the endometrium
–preparation of uterus to receive fertilized ovum
–if implantation does not occur, the stratum functionalis is shed during menstruation
•includes changes in the breast and cervix associated with the ovarian and uterine cycles.
•includes the hormonal changes that accompany the ovarian and uterine cycles.
19. Hormonal Regulation of Reproductive Cycle
•GnRH secreted by the hypothalamus controls the female reproductive cycle
stimulates the release of FSH and LH by the anterior pituitary gland
–FSH initiates growth of follicles that secrete estrogen
•estrogen maintains reproductive organs
–LH stimulates ovulation & promotes formation of the corpus luteum which secretes estrogens, progesterone, relaxin & inhibin
•progesterone prepares uterus for implantation and the mammary glands for milk secretion
•relaxin facilitates implantation in the relaxed uterus
•inhibin inhibits the secretion of FSH
20. Overview of Hormonal Regulation
21. Estrogens and Progesterone have several important functions:
•Estrogens works Promote of the development and maintenance of female reproductive structures, secondary sex characteristics, and the breasts.
•Estrogens works increase protein anabolism and build strong bones.
•Estrogens works to lower blood cholesterol.
•Moderate levels of estrogens in the blood inhibit the release of GnRH by the hypothalamus and secretion of LH and FSH by the anterior pituitary gland.
•Progesteroneworks with estrogens to prepare the endometrium for implantation
•Progesteroneworks prepare the mammary glands for milk synthesis.
•Progesteroneworks inhibits release of GnRH and LH
22. Overview of Female Reproductive Cycle
23. Hormonal Changes
24. Phases of the Female Reproductive Cycle
•The female reproductive cycle may be divided into four phases.
–The menstrual cycle(menstruation)
–First day is considered beginning of the 28 day cycle
–lasts for approximately the first 5 daysof the cycle.
•During this phase, small secondary follicles in each ovary begin to develop.
•the stratum functionalislayer of the endometrium is shed, discharging blood, tissue fluid, mucus, and epithelial cells.
25. Preovulatory Phase -days 6-13
•In the ovary (follicular phase)
–the time between menstruation and ovulation. This phase is more variable in length that the other phases.
•primary follicle develop into secondary follicle
•The dominant follicle continues to increase its estrogen production under the influence of an increasing level of LH
•develops into a vesicular ovarian (Graafian) follicle, or mature follicle
•In the uterus (proliferative phase)
–endometrial repair occurs
•increasing estrogen levels have repaired & thickened in the uterus
26. OvulationPhase -days 14
•Ovulationis the rupture of the vesicular ovarian (Graafian) follicle with release of the secondary oocyte into the pelvic cavity, usually occurring on day 14 in a 28-day cycle.
–high levels of estrogen during the last part of the preovulatory phase exert positive feedback on both LH and GnRH to cause ovulation (Figure 28.25).
–GnRH promotes release of FSH and more LH by the anterior pituitary gland.
–The LH surge brings about the ovulation.
•Corpus hemorrhagicum results
•In time, the follicular cells enlarge, change character Corpus hemorrhagicum, and form the corpus luteum
•Stimulated by LH, the corpus luteum secretes estrogens and progesterone.
27. Phases -Postovulatory -days 15-28
•Time between ovulation and onset of the next menstrual period. most constant timeline = lasts 14 days
•In the ovary (luteal phase)
–both estrogen and progesterone are secreted in large quantities by the corpus luteum.
–if fertilization does notoccur, then the corpus albicansis formed
–if fertilization doesoccur, then the developing embryo secretes human chorionic gonadotropin (hCG) which maintains health of corpus luteum & its hormone secretions
•In the uterus (secretory phase)
–hormones from corpus luteum promote thickening of endometrium to 12-18 mm
•formation of more endometrial glands & vascularization
–if no fertilization occurs, menstrual phase will begin
28. Fertilization
•If fertilization and implantation do occur, the corpus luteum is maintained
–The placenta will take over its hormone-producing function.
–During this time, the corpus luteum, maintained by human chorionic gonadotropin (hCG) from the developing placenta, secretes estrogens and progesterone to support pregnancy and breast development for lactation.
–Once the placenta begins its secretion, the role of the corpus luteum becomes minor.
•With reference to the uterus, this phase is also called the secretory phase because of the secretory activity of the endometrial glands as the endometrium thickens in anticipation of implantation.
29. Aging and the reproductive systems
•Puberty refers to the period of time when secondary sexual characteristics begin to develop and the potential for sexual reproduction is reached.
•In males, decreasing levels of testosterone decrease muscle strength, sexual desire, and viable sperm.
•Prostate disorders are increasingly common with age, particularly benign hypertrophy.
•In females, the reproductive cycle normally occurs once each month from menarche, the first menses, to menopause, the last menses.
•Between the ages of 40 and 50 the ovaries become less responsive to the stimulation of gonadotropic hormones from the anterior pituitary. As a result, estrogen and progesterone production decline, and follicles do not undergo normal development.
•In addition to the symptoms of menopause, such as hot flashes, copious sweating, headache, vaginal dryness, depression, weight gain, and emotional fluctuations, with age females also experience increased incidence of osteoporosis, uterine cancer, and breast cancer.
SUMMARY:
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https://www.youtube.com/results?search_query=female+Reproductive+System+animation+janux
https://www.youtube.com/results?search_query=menstrual+cycle+(menstruation)+animation+alila
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