front 1 Tunica intima | back 1 - Innermost layer - Contains endothelium: runs uninterrupted through entire cardiovascular system |
front 2 Internal, external elastic lamina | back 2 Present only in arteries |
front 3 Tunica media | back 3 Contains smooth muscle fibers (vasoconstriction) |
front 4 Tunica externa | back 4 Connective tissue that stabilizes blood vessels |
front 5 Structure and function of arteries | back 5 - Need to handle larger amounts of pressure from the heart - Have thicker walls, smaller lumens than veins |
front 6 Elastic arteries aka: | back 6 Conducting arteries |
front 7 Elastic arteries | back 7 - Includes aorta and its principal branches - Have large lumens to collect large volumes of blood from the heart |
front 8 Muscular arteries aka: | back 8 Distributing arteries |
front 9 Muscular arteries | back 9 - Have the largest tunica media of any blood vessel type; possess a great ability to vasoconstrict - Branch extensively to deliver blood to arterioles throughout the body |
front 10 Arterioles | back 10 Smallest artery type |
front 11 Largest arterioles | back 11 - Still contain all three tunics - Resemble small muscular arteries |
front 12 Tiniest aerterioles | back 12 Simply endothelium surrounded by 1-2 fiber layers of smooth muscle |
front 13 ___ of arterioles regulates blood flow into capillary beds | back 13 Diameter |
front 14 Resistance vessels | back 14 Arterioles that change their diameter to allow more or less blood flow |
front 15 Metabolic responses | back 15 Adjust blood flow based on specific demands of local tissue - Ex: increased NO release during exercise |
front 16 Myogenic responses | back 16 Occur reflexively within smooth muscle of tunica media - Ex: increased pressure causes contraction |
front 17 Capillaries | back 17 - Smallest blood vessel type, so erythrocytes flow in single file - Site of gas and nutrient exchange: only tunic intima is present, and is permeable |
front 18 Continuous capillaries | back 18 - Most common type - Lining does not contain pores - Exchange occurs through intercellular clefts and pinocytic vessels |
front 19 Fenestrated capillaries | back 19 - Endothelial cells dotted with pores - More readily allows passage of fluid and larger molecules |
front 20 Sinusoid capillaries | back 20 - Have larger fenestrations and a discontinuous basement membrane - Allow movement of entire cells through barrier |
front 21 Organization of capillaries into capillary beds | back 21 - Precapillary sphincters - Terminal arteriole - Metarteriole - True capillaries - Thoroughfare channel - Vascular shunt - Postcapillary venule |
front 22 Precapillary sphincters | back 22 Bands of smooth muscle that encircle each true capillary at its origin from a metarteriole |
front 23 Terminal arteriole | back 23 Delivers blood to capillary bed |
front 24 True capillaries | back 24 Vessels of exchange: branch off the metarteriole, converge upon the thoroughfare channel |
front 25 Postcapillary venule | back 25 Drains blood away from capillary bed |
front 26 Vascular shunt | back 26 Directly connects the terminal arteriole to the postcapillary venule |
front 27 Thoroughfare channel | back 27 Arises from the metarteriole; returns blood to postcapillary venule |
front 28 Metarteriole | back 28 Arises from the terminal arteriole |
front 29 Venules | back 29 - Smallest of vessels carrying blood back to the heart - Have all three tunics, but very thin - Have large lumens: blood reservoirs or capacitance vessels |
front 30 Venyles converge to form ___ | back 30 Veins |
front 31 Systemic veins- blood volume | back 31 64% |
front 32 Systemic arteries- blood volume | back 32 13% |
front 33 Systemic capillaries- blood volume | back 33 7% |
front 34 Pulmonary circulation- blood volume | back 34 9% |
front 35 Heart- blood volume | back 35 7% |
front 36 Veins contain ___ | back 36 Valves |
front 37 Veins experience much lower pressure than ___ | back 37 Arteries |
front 38 To ensure blood returns to heart: | back 38 - Large lumens offer less resistance to blood flow - Venous valves (specialized foldings of the tunica intima) ensure unidirectional blood flow |
front 39 Large lumens offer ___ resistance to blood flow | back 39 Less |
front 40 Venous valves (specialized foldings of the tunica intima) ensure ___ blood flow | back 40 Unidirectional |
front 41 What are varicose veins? | back 41 Failure of venous valves, allowing blood to pool in peripheral veins of legs |
front 42 Varicose veins- causes | back 42 Anything that impedes venous return (pregnancy, obesity, prolonged periods of standing) |
front 43 Varicose veins- symptoms | back 43 Dilation and distension of veins, sometimes causing discomfort or pain |
front 44 Blood flow (F) | back 44 Volume of blood moving through a vessel, tissue, organ or entire circulation per unit of time |
front 45 Blood pressure (BP or P) | back 45 Force exerted onto a given area of the vessel wall by the blood contained within it, measured in mm Hg |
front 46 Resistance (R) | back 46 Friction encountered by blood, impeding its flow |
front 47 F = | back 47 Delta P/ R |
front 48 Three variables influence resistance | back 48 - Blood viscosity - Blood vessel length - Blood vessel radius |
front 49 Poiseuille's equation | back 49 Delta P = 8nLF/pi(r)4 |
front 50 Rearranging for F | back 50 F = pi(delta)(P)(r)4/8nL |
front 51 Orignal equation | back 51 R = delta P/F |
front 52 Substituting F with poiseuille's equation | back 52 R = 8nL/pi(r)4 |
front 53 Delta P | back 53 Difference in pressure between two points |
front 54 n | back 54 Viscosity of the bluid |
front 55 L | back 55 Length of the tube |
front 56 F | back 56 Rate of flow |
front 57 Pi | back 57 Mathematical constant |
front 58 r | back 58 Radius of the tube |
front 59 Total peripheral resistance (TPR) | back 59 - Used to describe forces impeding blood flow throughout the entire circulation - Mainly due to veins, not arteries |
front 60 Flow is normally ___, but abrupt changes in diameter can lead to ___ flow, increasing ___ | back 60 Laminar; turbulent; resistance |
front 61 Blood vessels exhibit ___ | back 61 Compliance - Ability to change structure in response to changes in pressure |
front 62 Mean arterial pressure = | back 62 Diastolic blood pressure + Pulse pressure/3 |
front 63 Capillary blood pressure and exchange | back 63 - CHP - IFHP - BCOP - IFCOP |
front 64 CHP | back 64 Pressure exerted by blood onto capillary wall |
front 65 - IFHP - BCOP | back 65 Pressure opposing filtration |
front 66 IFCOP | back 66 Pressure exerted by proteins in interstitial fluid |
front 67 Net filtration pressure = | back 67 (CHP + IFCOP) - (IFHP + BCOP) |
front 68 Pressure in veins is much ___ than arteries | back 68 Lower |
front 69 Muscular pump assists venous return | back 69 During contraction, bulging muscles compress veins, forcing blood back towards the heart |
front 70 Respiratory pump also assists venous return | back 70 During inspiration, intrathoracic pressure decreases, drawing blood towards the thoracic cavity |
front 71 Blood pressure varies with ___ and ___ | back 71 Cardiac output; peripheral resistance |
front 72 MAP = CO x TPR (1) | back 72 Increasing either cardiac output or peripheral resistance increases blood pressure |
front 73 MAP = CO x TPR (2) | back 73 CO = SV x HR Increasing either stroke volume or heart rate increases cardiac output |
front 74 Nervous control of blood pressure | back 74 Baroreceptors |
front 75 Receptors (BP increased) | back 75 - Baroreceptors in various locations are stimulated - More impulses sent to cardiovascular center |
front 76 Control center (BP increased) | back 76 - Cardioinhibitory center is excited - Cardioacceleratory and vasomotor centers are inhibited |
front 77 Effectors (BP increased) | back 77 - Heart: HR and contractility decrease - Blood vessels: vasodilation - Lowered CO and R will lower BP |
front 78 Receptors (BP decreased) | back 78 - Baroreceptors in various locations are inhibited - Fewer impulses sent to cardiovascular center |
front 79 Control center (BP decreased) | back 79 - Cardioacceleratory and vasomotor centers are excited - Cardioinhibitory center is inhibited |
front 80 Effectors (BP decreased) | back 80 - Heart: increased HR and contractility - Blood vessels: vasoconstriction - Increased CO and R will increase BP |
front 81 Other methods of blood pressure control | back 81 - Chemoreceptors - Higher brain centers - Endocrine factors |
front 82 Chemoreceptors | back 82 - Monitor oxygen, carbon dioxide, hydrogen ion contents of blood - Objective: change cardiac output and blood pressure to meet varying metabolic needs of body |
front 83 Higher brain centers | back 83 - Cerebral cortex and hypothalamus also relay information - Communicate with the limbic system; cause of physical manifestation of emotions |
front 84 Endocrine factors | back 84 - Antidiuretic hormone (ADH): aka. vasopressin; causes vasoconstriction - Thromboxane and serotonin: cause vasoconstriction - Epinephrine and norepinephrine: cause vasoconstriction |
front 85 Aging effects on circulation | back 85 - Blood vessels stiffen and narrow due to loss of elasticity, decreased vessel compliance and accumulation of fatty deposits (plaques) - Stiffened blood vessels cause heightened MAP, which further stiffens blood vessels -> vicious cycle - Increased risk of myocardial infarction (MI) - Cardio-protective estrogen effects are lost in post-menopausal women |