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Mercer County Community College Science & Allied Health Division Bio 104 Lecture Outline Chapters 17, 18, 19, 20 Course Coordinator: L. Falkow Revised 1/06 The Cardiovascular System Introduction & Overview of the CV System Science Pulmonary circuit Systemic circuit: Coronary circulation: Arteries Capillaries Veins Anatomy of the Heart A. Location & Size 1. Mediastinum 2. Size B. Pericardium 1. fibrous pericardium 2. serous pericardium parietal pericardium [pericardial cavity] visceral pericardium 3. Disorders pericarditis cardiac tamponade 2 C. Superficial Anatomy Auricle Coronary sulcus Interventricular sulcus Base Apex D. Internal Anatomy 4 Chambers: 2 atria and 2 ventricles 1. Right Atrium SVC IVC Coronary sinus Foramen ovale < Right atrioventricular (AV) valve> 2. Right Ventricle chordae tendinae papillary muscles <Pulmonary Semilunar valve> _____________ LUNGS _________________ 3. Left Atrium <Left Atrioventricular (AV) valve> 4. Left Ventricle <Aortic Semilunar valve> ascending aorta openings to coronary arteries 3 5. Structural differences between ventricles RV wall – LV 6. Heart valves AV valves: Semilunar valves: E. Heart Wall 1. Epicardium 2. Myocardium 3. Endocardium cardiac muscle tissue characteristics F. Coronary Circulation 1. Right coronary artery └> marginal branch └> posterior interventricular branch (post. descending artery) 2. Left coronary artery └> circumflex branch └> anterior interventricular branch (left anterior descending artery) 3. Coronary veins great cardiac vein └> coronary sinus ________________ G. Cardiac Muscle Cells Contractile cells do the pumping (99%) of all cardiac cells. Conducting system (specialized cells) regulate actions of contractile cells. 4 Conduction System and ECG A. Conducting system includes: Nodal tissue SA (sinoatrial) node AV (atrioventricular) node AV bundle (of His) Bundle branches Purkinje fibers ACh (PSN) Ectopic pacemakers B. Electrocardiogram (ECG) - measure of electrical changes that accompany each cardiac cycle (heartbeat) 1. Wave forms: P wave QRS complex T wave 2. Intervals P-R interval: Q-T interval: 3. Conduction system problems a. heart block ex. SA node block AV node block b. arrhythmias bradycardia < 60bpm tachycardia >100bpm 5 C. Cardiac Cycle 1. Consists of: systole – contraction phase diastole – relaxation phase 2. Average heartrate: ~75 bpm (70-80bpm) 3. Heart sounds auscultation “lubb” = “dupp” [MVP] mitral valve prolapse murmur - Cardiodynamics - movements & forces during contractions of the heart A. Cardiac Output CO = HR x SV HR = heartrate (bpm) SV = stroke vol. (ml/beat) Normal CO: CO = HR x SV During exercise: CO = HR x SV B. Factors affecting stroke volume [ EDV, ESV, ventricular stretching, contractility, hormones] 1. The EDV EDV [end diastolic volume] = amt. blood in ventricle at end of diastole (start of vent. systole) 6 2. The ESV ESV [end systolic volume] = amt. of blood in ventricle after contraction (at start of vent. diastole) 3. Frank-Starling principle (Starling’s law of heart} “more in = more out” 4. Contractility 5. Hormones C. Factors affecting heart rate [ ANS, Atrial reflex, Hormones, Venous return] 1. ANS Innervation CAC (cardioacceleratory center) CIC (cardioinhibitory center) 2. Atrial reflex (Bainbridge) 3. Hormones 4. Venous Return D. Exercise and Cardiac Output C.O. varies to needs of body; metabolic needs of the cell. athlete nonathlete 7 Blood Vessel Anatomy Arteries Arterioles Capillaries Venules Veins A. Structure of vessels 1. 3 basic layers (tunics) a. tunica interna (intima) <internal elastic lamina or membrane> b. tunica media (middle coat) <external elastic lamina or membrane> c. tunica externa (adventitia) 2. Arteries - 3 layers: tunica interna tunica media tunica externa - highest pressure [ ] Elastic arteries (conducting) Ex. Muscular arteries (distribution arteries) Ex. 3. Arterioles - resistance vessels - greatest change in pressure [ ] As arteries ____in size elastic tissue ____ smooth muscle ____ Elastic arteries can withstand sudden _____ in BP as blood leaves the heart. 8 Arterioles can regulate distribution of blood to different capillary beds by ______ and _____ . 4. Capillaries - one cell thick - low pressure [ ] a. Continuous capillaries BBB b. Fenestrated capillaries c. Capillary beds precapillary sphincter anastomosis 5. Venules - 2 layers thick (interna, externa) 6. Veins - 3 layers - low pressure [ - reservoir - valves: - muscle pump: ] - respiratory pump: B. Structural differences between Arteries and Veins Arteries Wall thickness: X-section: Tunica media: Elastic fibers: Valves: Veins 9 Cardiovascular Physiology A. Pressure and Resistance Hydrostatic pressure (HP) Circulatory pressure Blood pressure (BP) Peripheral resistance (PR) B. Overview of CV Pressures 1. Vessel diameter 2. Total cross-sectional area 3. BP 4. Velocity C. Capillary Exchange - movement of materials across capillary walls: 1. Diffusion - water, ions, small organic molecules, water-soluble, lipid soluble 2. Filtration - hydrostatic pressure forces water & small solutes across capillary wall Capillary hydrostatic press. (CHP) = BP in capillary 3. Reabsorption Osmotic pressure (OP) = water drawing power Blood colloid osmotic pressure (BCOP) = blood proteins draw fluids into capillary 4. Interplay between Filtration and Reabsorption Net hydrostatic pressure = [CHP-IHP] [tends to move H2O & solutes out of cap.] CHP (capillary hydrostatic pressure) arterial end = 35 mmHg; venous end = 18 mmHg IHP (hydrostatic press. of interstitial fluid) [~ 0 mmHg] 10 Net colloid osmotic pressure: [tends to pull H2O & solutes into cap.] BCOP (blood colloid osmotic press.) ICOP (interstitial fluid osmotic press.) NET FILTRATION PRESSURE = Net hydrostatic pressure - Net colloid osmotic pressure (NFP) = (CHP - IHP) (BCOP – ICOP) Arterial end: NFP = (35-0) - (25-0) = 10 mmHg {moves fluid out of cap.} Venous end: NFP = (18-0) - (25-0) = -7 mmHg {moves fluid into cap.} :. more Filtration occurs than Reabsorption and excess fluid flows into lymphatic vessels ----> venous (blood) circulation Edema: = excess fluid in interstitium (fills spaces between cells) Causes: 1) damage to capillaries: 2) starvation: 3) increased BP: 4) blockage of lymphatic vessels: 5) kidney damage: Cardiovascular Regulation A. Autoregulation 1. Local VD 2. Local VC: 11 B. Neural Control CV center in brain = 1. Baroreceptors - monitor stretch in vessel walls carotid sinus aortic sinus atrial baroreceptors If BP increases… what happens ? 1. 2. If BP decreases… what happens? 1. 2. 2. Chemoreceptors - respond to changes in CO2, O2, pH in blood & CSF carotid bodies aortic bodies If CO2 or pH or O2 C. Hormones ADH (Antidiuretic Hormone) - post. pituitary - promotes water retention; released when decr. blood vol. [conserves water] Angiotensin II ACE - Angiotensin I ---------> Angiotensin II in lungs - powerful VC; incr. BP [Drugs called ACE-inhibitors] - stim. thirst EPO (Erythropoietin) - from kidneys, released if BP decr. or [O2] decr. - stim. RBC production 12 ANP (Atrial Natriuretic Peptide ) - from heart (RA); - released when chamber wall stretches during diastole; - reduces blood vol. & BP D. CV Response to Hemorrhage 1. Short-term elevation of BP 2. Long-Term restoration of blood vol. Selected Blood Vessels A. Pulmonary circulation Pulmonary arteries Pulmonary veins B. Systemic Circulation 1. Aorta Ascending aorta: right & left coronary arteries Aortic arch: 1) 2) 3) Descending aorta 2. Hepatic portal circulation - inferior mesenteric vein - splenic vein - superior mesenteric vein Splenic v. & superior mesenteric v. join to form hepatic portal vein --> liver 13 3. Fetal circulation umbilical arteries (2) - drain deoxygenated blood from fetus umbilical vein (1) - carries oxygenated blood from placenta Placenta --> umbilical v. --> ductus venosus to liver --> IVC --> RA ---> foramen ovale --> LA ---> LV --> aorta (head & upper extremities) Blood from upper extremities --> SVC --> RA --> RV (mostly) pulm. artery (lungs) but most flows through ductus arteriosus to aorta --> rest of body---> return via umbil. arteries to placenta Tetralogy of Fallot: “blue baby” -> 4 defects: Pulmonary stenosis Enlarged RV Ventricular septal defect Patent ductus arteriosus Blood A. Functions 1. Transportation nutrients wastes respiratory gases heat hormones 2. Regulation pH electrolytes body temp. (VC, VD) 3. Restriction 4. Defense B. Physical Characteristics 1. viscosity: 2. pH: 3. volume: 4. specific gravity: 5. Hct: 14 Components of Blood A. Plasma [~55%] 1. Differences between plasma & interstitial fluid Components of plasma: 92% - water 7% plasma proteins 1% other stuff (electrolytes, nutrients, and wastes) 2. Plasma proteins - albumins [60%] - globulins [35%] - fibrinogen [4%] B. Formed Elements [~45%] 1. Erythrocytes RBCs 2. Leukocytes WBCs 3. Thrombocytes Platelets C. Hemopoiesis - production of formed elements stem cells hemocytoblasts myeloid stem cells lymphoid stem cells all formed elements except lymphocytes lymphocytes HemopoiesisSites of production: D. Erythrocytes 1. Abundance 15 RBC count: Hct: 2. Structure 3. Hemoglobin Hb globin: protein part heme: Fe-containing pigmented part Hb + O2 ----> HbO2 (reduced (oxyhemoglobin) hemoglobin) 4. RBC Lifespan & Circulation 5. Erythropoiesis - RBC production 6. Blood Types Type A Type B Type AB Type O RBC antigen A antigen B antigens A,B none Plasma anti-B antibodies anti-A antibodies none anti-A & anti-B antibodies agglutinogens = surface antigens Rh factor: Rh positive = Rh negative = 16 cross-reaction - antibody meets its specific antigen => clumping of RBCs HDN (hemolytic disease of the newborn) or erythroblastosis fetalis - mother is Rh neg., baby is Rh pos. 1970’s: Rho-Gam 7. Clinical disorders anemia hematuria hemophilia E. Leukocytes 1. Characteristics - nucleated Lifespan: a few hours to a few days WBC count: 2. Types Granulocytes: Neutrophils Eosinophils Basophils % Description 50-70% multi-lobed nucleus 2-4% 2-lobed nucleus, red granules <1% dk.blue granules, obscure nucleus Agranulocytes: Lymphocytes 20-30% round nucleus, little cytoplasm Monocytes 2-8% Kidney bean shaped nucleus Function phagocytosis incr. during allergic rxn. inflam. response immune response macrophages 17 3. Formation Red bone marrow: Lymphoid tissue: 4. Clinical leukopenia leukocytosis F. Thrombocytes 1. Characteristics 2-4 μm cell fragment 150,000 - 500,000 /mm3 [avg. 350,000] 9-12 days 2. Functions - blood clotting 3. Formation megakaryocytes 4. Clinical thrombocytopenia thrombocytosis Hemostasis - prevention of blood loss A. Vascular phase vascular spasm - VC of SMC B. Platelet phase platelet plug formation platelets release: C. Coagulation phase clotting factors: extrinsic & intrinsic pathways 18 Lymphatic System A. Functions 1. production of lymphocytes 2. return lymph (tissue fluid) to venous circulation 3. distribution of hormones, nutrients, and wastes to circulation B. Lymph vessels lymphatic capillaries --> vessels (lymphatics) ---> cisterna chyli --> thoracic duct ==>left subclavian vein --> right lymphatic duct => rt. subclavian v. C. Lymph tissues Tonsils Lymph nodes Thymus Spleen Aggregate lymphoid nodules Appendix