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HHP Ch 13
Cardiovascular System
| Question | Answer |
|---|---|
| Define the components of the cardiovascular system | • Blood – Transport medium (cells suspended in fluid) • Heart – Pump – drives circulation of blood • Blood vessels – Tubing that conducts blood through circulation |
| Describe the components of blood | 8% total body weight, average blood V 5L -Erythrocytes (RBC) -Leukocytes (WBC) -Thrombocytes - Platelets (cell fragments) -Plasma (liquid portion of blood comprised of proteins, nutrients, hormones, electrolytes) |
| Identify the formed elements of blood | -Erythrocytes (RBC) -Leukocytes (WBC) -Platelets (cell fragments) see images to practice ID |
| Describe the composition of plasma | 90% H2O 7-9% protein |
| Describe erythrocytes | RBC, no nucleus or organelles contain hemoglobin (iron binds to O2 to carry O2. 4O2/RBC) Structure: biconcave discs (provides larger SA for diffuse O2) and flexible membrane (llows RBC to travel thru narrow capillaries wo rupturing) |
| Describe the regulation of red blood cell production OVERVIEW | Erythropoiesis RBCs survive ~120 days and must be replaces at rate 2-3mil/sec Erythropoiesis occurs in bone marrow: multipotent hematopoietic stems cells (blood cells that can differentiate into diff blood cells) |
| Explain hemostasis and the role of platelets and coagulation proteins | prevents blood loss from broken blood vessel. 1. vascular spasm (reduces blood flow thru damaged vessel) 2. formation of platelet plug (pile on contact w exposed collagen, release ADP-> sticky surface 3. blood coagulation (clot) (coag. Prot in blood) |
| Differentiate between extrinsic pathway of coagulation and intrinsic pathway of coagulation | Intrinsic- activated by exposed collagen Extrinsic- released from damaged tissue final share a common pathway ending w fibrinogen->fibrin *study image |
| Describe the structure of the heart, including valves, and blood flow through the heart | hollow, muscular organ located in thoracic cavity 2 atria, 2 ventricles constantly pumps (variable rate tho) 2 circuits: systemic and pulmonary *image |
| Explain how valves open and close | when P greater behind valve, opens when P greater in front, closes |
| Distinguish between the systemic and the pulmonary circulation. | P: DeO2 blood enter from body to R heart , exit to Lungs S:O2 enter from lungs to L heart, exit to body |
| Compare the two types of heart cells, including the electrical activity in each | Autorhythmic cells • Do not contract • Initiate AP's and spread impulse throughout heart Contractile cells • 99% of cardiac muscle cells • Do mechanical work of pumping • Normally dont initiate own AP |
| Describe the cardiac cycle in terms of systole and diastole OVERVIEW | Systole: atria are relaxed, vernicles contract (.3sec) Diastole 1: atria and ventricles relax. ventricles fill when relax Diastole 2 atria contracts while ventricles relax and fill see image |
| Explain how the pressure differences within the heart chambers are responsible for blood flow during the cardiac cycle. | High P to Low P |
| Describe excitation-contraction coupling in heart muscle | similar to skeletal. Differences: AP Rate of AP Calcium released |
| Describe the conduction system of the heart | Autorhythmic Cells Sinoatrial node AP spreads thru L+Ratria AV node conduction delay (time to fill) Bundle of His -> Purkinje fibers -> Myocardial Cells |
| Explain an ECG, including the various waves, and uses | Record of overall spread of electrical activity (EA) through heart (X 1 AP) EA is associated w mechanical movement (myocard various waves: P Q,R,S T associate w myocardial cell work- when atria and ventricles contract *image |
| Compare the structures of (venous) pulmonary and (arterial) systemic LARGE VESSELS (arteries and veins) | similar: layers- tunica externa media and interna differences: arteries ^ smooth muscle bc more bp regulation. veins ^ hollow to carry more blood, have valves to carry blood up to heart |
| Explain the refractory period of the heart, and it’s importance | After an action potential initiates, the cardiac cell is unable to initiate another action potential for some duration of time. prevents tetanus :0 |
| Define vasoconstriction and vasodilation | -vasodilation: blood vessels dilate -vasoconstriction: vessel contract -Due to a contraction of vessel smooth muscle -affects blood flow |
| Explain the causes and risk factors of atherosclerosis. (causing the leading cause of death in the US- coronary artery disease) | vessel scarring, plaque buildup. Risk factors: smoking, obesity, sedentary, genetics |
| Explain how the lymph and lymphatic system relate to the blood and cardiovascular system. | lymph from interstitial fluid, enters through capillaries aids immune system (removes pathogens), removal of interstitial flue and return unidirectional to heart, absorbs and transports fatty acids to liver |
| Function of H2O in plasma | dissolves materials (gases, nutrients, etc) acts as fluid for transport |
| Function of Proteins in plasma | maintain osmotic pressure in blood (albumins) lipid transport immunity (antibodies) clotting factors various enzymes |
| Describe the regulation of red blood cell production | Reduced O2 carrying capacity lets kidney know to release erythropoietin into blood. Sent to bone marrow where it stimulates HSC, HSC-erythrocytes then sent into blood for increase blood carrying capacity This is why ^aerobic fitness =^ RBC (more O2) |
| Describe and give causes for anemia | Refers to a below normal O2 carrying capacity of the blood. Causes: dietary deficiencies (XB12= X production RBC) Xiron=poor hemoglobin), blood loss (mensuration, ulcers), bone marrow failure (cancer, chemo), hemolytic anemia (B12) |
| Describe thrombocytes | Colorless cell fragments – Lack nuclei – Have organelles • Come from Megakaryocyte cell • Function in hemostasis • Thrombopoietin – Hormone produced by liver increases number of megakaryocytes and therefore increases platelet production |
| Platelets activate...so that... *note. S=soluble, IS=insoluble | clotting factors so that clots can reinforce platelet (factors are always present in plasma in inactive precursor form. Vessel damage initiates cascade of Rxns that involve successive activation of clotting factors. ex S fibrinogen-> IS fibrin) |
| Describe Leukocytes | WBC. immune defense. immu system: recognizes and destroys or neutralizes foreign to normal self materials. WBC: defends against pathogens, ID and destroys cancer cells, "cleanup crew" removing worn out cells or debris |
| Describe pulmonary circuit (blood flow) | Deoxygenated blood enters R side through vena cavae → R atrium → RAV valve → R ventricle → pulmonary semilunar valve → pulmonary trunk and arteries → lungs (pulmonary circuit) |
| Describe systemic circuit (blood flow) | Oxygenated blood enters L side through pulmonary veins →L atrium → L AV valve → L ventricle → aortic semilunar valve → aorta → tissues (systemic circuit) |
| Describe the cardiac cycle: systole | 1. Isovolumetric contraction – Ventricles contract, but no blood ejected – BP rises above P in atria – AV valves shut 2. Ejection – BP in ventricle exceeds pressure in arteries – Blood flows out of ventricles, causing P in ventricles to fall |
| Describe the cardiac cycle: diastole | 1. IsoVtric Relaxation – P in vent drops v arterial P – SL valves prevent backflow of blood – X change in ventricular volume 2. Rapid filling – P in vent falls v atrial P – AV valves open, allowing blood flow into vent 3. Atrial contraction |
| Heart beats via autorhythmicity? what is autorhythmicity? | cells are able to generate the action potential at a certain rate without any external stimulus due to which the heart beats continuously and rhythmically. |
| Mechanism of Autorhymicity. How autorhymic cells initiate APs | membrane permeability changes w AP (K-Na) (Ca) Pacemaker Potential depend on Hyperpolarization Cyclic Nucleotide (HCN) channels, funny (Na) channels (these open when membrane hyperpolarizes) depolarization due to Ca2+ *see image |
| electrical activity of myocardial cells | AP- depolarization->plateau (due to slow Ca2+in, K+out. this si goo dbc gives time to contract and relax), repolarization (K+rush out) *see image |
| describe coronary circulation. coronary vessels (CV) | muscle is supplied w O2 and nutrients by coronary circulation (not from blood within heart chambers) CV provide blood to heart during diastole. During systole, CV are compressed by heart muscle blow flow normally varies w cardiac O2 needs |
| What is the vascular tree? | closed system of pulmonary and systemic vessels Arteries->Arterioles->Systemic Capillaries->Venules->veins V>V>Pulmonary Capillaries>A>A |
| What is the only vein that carries O2 to the heart? What is the only artery that carries deoxygenated blood away from the heart? | pulmonary vein, pulmonary artery |
| Compare the structures of (venous) pulmonary and (arterial) systemic vessels: arterioles and venules | venule tunica externa, endothelium, valve arteriole endothelium, lumen, precapillary sphincter |
| Compare the structures of (venous) pulmonary and (arterial) systemic capillaries | pulmonary/fenestrated and systemic/continuous have endothelial cells, capillary pores, and basement membranes |
| largest vein/ largest artery | vein: inferior vena cava artery: aorta |
| Function of arteries | -take blood away from heart -low resistance elastic conduits (due to large radius, arteries offer little resistance) -pressure reservoir (to provide driving force for blood when heart is relaxing |
| Function of arterioles | -distribute cardiac output among systemic organs depending on needs (vasoconstriction and vasodilation. -controlled by intrinsic (vessel diameter) and extrinsic factors (sympathetic/para) |
| Structure of capillaries | -thin walled, extensively branches (maximizes SA and minimized diffusion distance) -contain pre-capillary spinsters (smooth muscle at the arterial end of a capillary and serving to control the flow of blood to the tissues) think control valves |
| Function of capillaries | – Sites of exchange between blood and surrounding cells • Only Tunica Intima |
| Describe the different types of capillaries | -continuous- small gaps w cells. muscle and lungs -fenestrated- plasma membranes have holes. kidney, small intest, endocrine glands -discontinuous- large fenestrations, incomplete basement member, live, bone marrow, spleen |
| Function of veins | -return blood to heart -blood reservoir |
| Function of veins | -large radius offers little resistance to blood flow -low P system -valves |
| Factors enhancing venous return -- protection against gravity | -driving P from cardiac contraction -sympathetically induces venous vasoconstriction -skeletal muscle activity (contraction pumps, ^activity=^blood to R heart) -venous valves (X backflow) -body position (use of gravity) |
| Lack of lymphatic system function leads to what? | Edema: swelling caused by excess fluid trapped in your body's tissues. |
| Describe excitation-contraction coupling in heart muscle vs skeletal: AP | cardiac: AP conducted from cell to cell skeletal: AP conduction along length of a single fiber |
| Describe excitation-contraction coupling in heart muscle vs skeletal: rate of AP propagation | cardiac: slow bc gap junctions and small diameter of fibers. good bc allows heart to rest and fill skeletal: faster due to large diameter fibers |
| Describe excitation-contraction coupling in heart muscle vs skeletal: calcium release | cardiac: movement of extracellular Ca2+ thru plasma membrane and T tubules into SR stimulates release of Ca2+ from SR skeletal: AP in T tubules stimulates Ca2+ release from SR |
| Pacemaker Potential | rests at 20+ mV. hyperpolarizes w K+ leaving to ~55mV where Na+ channels open. Depolarization. Ca2+ opens at ~40 |
Created by:
kellyyrosse
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