Term
| function of smooth muscle |
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Definition
| control diameters of blood vessels and generates force to move material through lumen of an organ |
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Term
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Definition
| composed of discrete, independently innervated fibers; control exerted mainly by nerve signals (ciliary muscles of the eye); sparse gap junctions |
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Term
| single-unit smooth muscle |
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Definition
| arranged in sheets or bundles and cell membranes contact to form gap junctions so ions flow freely; rarely exhibit spontaneous contraction |
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Term
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Definition
| serve same function as Z disks in skeletal muscle where loose bundles of muscle filament are attached |
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Term
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Definition
| connects to other end of thin filaments in smooth muscle located at the plasma membrane |
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Term
| response to which smooth muscle contracts |
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Definition
| due to either neuromuscular synaptic transmission or pharmacoelectrical coupling |
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Term
| differences between smooth muscle and skeletal muscle |
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Definition
| smooth muscle creates and maintains tension for long period of time, requires much less energy for contraction; velocity of contraction much slower, can shorten much more |
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Term
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Definition
| "resting" state of long-term, steady contraction called a tonus contraction; most result from prolonged direct smooth muscle excitation by paracrine or circulating hormones |
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Term
| sress-relaxation of smooth muscle |
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Definition
| change its length greatly without marked changes in tension; results from rapid remodeling of loose arrangement of the actin and myosin filaments |
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Term
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Definition
| molecular makeup of SMC enables a basal level of tone |
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Term
| inputs that initiate SMC contraction/relaxation |
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Definition
| 1. intrinsic tone; 2. nervous system (sympathetic nerves); 3. hormonal; 4. myogenic autoregulation (stretch of SMC will cause constriction); 5. metabolic substances; 6. paracrine substances |
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Term
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Definition
| varies depending on anatomical location but normally 30mV lower than skeletal muscle |
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Term
| forms of electromechanical coupling |
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Definition
| 1. action potential dependent-slower than in skeletal muscle because more Ca channels and less Na channels; 2. graded depolarization-stimulus causes depolarization and contaction without action potential and varies slowly in response to neurotransmitters and hormones |
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Term
| pharmacomechanical coupling |
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Definition
| contraction without change in membrane potential caused by local tissue factors and hormones; opens Ca channels and decrease potential and depolarize the membrane slightly but no action potential |
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Term
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Definition
| causes contraction; enters the cell via plasma membrane Ca channel and occur much more slowly allow for slow contraction and tension; lacks troponin so cannot turn rapidly on and off |
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Term
| calcium excitation contraction mechanism |
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Definition
| Ca ions activate the ATPase activity of myosin head |
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Term
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Definition
| calcium ions bind and the complex binds to and activates myosin light chain kinase |
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Term
| myosin light chain kinase |
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Definition
| when activated it phosphorylates and activates one of the light chain polypeptides of myosin head which turns on ATPase activity of the head to intitiate contraction |
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Term
| sources of Ca in smooth muscle |
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Definition
| 1. voltage-independent channels; 2. intracellular-Ca release from SR by IP3; 3. extracellular fluid through voltage gated channels |
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Term
| removal of Ca to terminate contraction |
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Definition
| 1. sequestration-Ca pumped from cytoplasm back into SR; 2. Na/Ca exchange which depends on membrane potential |
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Term
| myosin light chain phophatase |
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Definition
| removes phosphate from MLC preventing its reattchment to actin leading to relaxation |
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Term
| ways to modulate calcium sensitization |
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Definition
| 1. one way is to inhibit MLCP through GPCR; 2. phosphorylation of MLCK making it less efficient |
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Term
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Definition
| a low energy consumption, high tension state occurs when MLCP dephosphorylates MLC while mysoin is still attached to actin |
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Term
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Definition
| binds to actin filaments at low Ca, restricting ability of myosin to bind to actin and preventing contraction |
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Term
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Definition
| phosphorylates caldesmon so it cannot bind to thin filaments and unable to inhibit myosin binding; stimulated through PKC, Ras and heterotrimeric G proteins |
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Term
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Definition
| Arg dependent mechanism and NO diffuses from endothelial cells to smooth muscle cells which activates guanylate cyclase to increase cGMP |
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Term
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Definition
| activates a protein kinase that decrease intracellular Ca and decrease in Ca sensitivity of proteins in contractile system |
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Term
| transport of lipophilic substances across endothelial cells |
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Definition
| have entire capillary surface available for diffusion |
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Term
| endothelial diffusion of lipid-insoluble molecules |
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Definition
| restricted to pores in the capillaries and degree of restriction depends on molecular size |
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Term
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Definition
| governs net transfer of molecules from areas of high concentration to areas of low concentration; J=-P*A(Cinside-Coutside); with A depending on number of capillaries being perfused |
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Term
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Definition
| occurs due to pressure gradients and only small fraction (1-2%) of plasma is filtered as it passes through the capillaries |
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Term
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Definition
| due to blood pressure and forces fluid out into interstial fluid |
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Term
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Definition
| opposes filtration and functions in absorption but due to molecules that impermeable and generate osmotic force (plasma proteins) |
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Term
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Definition
| fluid movement=k[(Pc+pii)-(Pi+pip)]; k is reflected in hydrolic conductivity and SA availability |
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Term
| icreases in precapillary resistance |
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Definition
| blood flow will decrease and lower downstream pressure through the capillaries |
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Term
| increase in postcapillary resistance |
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Definition
| there will be increase in pressure across capillaries which will cause and increase in filtration |
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Term
| paracrine factors of the endothelial cells |
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Definition
| 1. NO (produced in response to sheer forces); 2. protagladins; 3. enothelin; 4. cytokines (molecules that help cell communication) |
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Term
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Definition
| long lasting potent vasoconstricor in abnormal circumstances |
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Term
| adhesion molecule involved in WBC and endothelial interaction |
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Definition
| 1. mucin-like CAMs; 2. selectins; 3. Ig-superfamily CAMs; 4. integrins |
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Term
| rolling and adhesion of WBC and platelets |
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Definition
| Mucin-like CAMs recognize selectins on endothelial cells and they start rolling and eventually interaction by integrins and If-superfamily CAMs cause stronger connection and intitiate diakinesis |
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Term
| adhesion molecules in between endothelial cells |
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Definition
| 1. tight junctions-include claudins, occludins, and junctional adhesion molecules; 2. adherens junctions- cadherin-catenin complexes |
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Term
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Definition
| requires dissolution of basement membrane and activation of endothelial cells requiring balance of stimulatory and inhibitory factors |
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Term
| promoters of angiogenesis |
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Definition
| 1. VEGF; 2. FGF; 3. Angiopoietin-1; 4. angiogenin |
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Term
| inhibitors of angiogenesis |
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Definition
| 1.angiostatin; 2. endostatin; 3. angiopoietin-2 |
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Term
| mean circulatory pressure |
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Definition
| pressure as a function of blood volume and compliance with no flow |
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Term
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Definition
| made to flow by pumping blood from venous system to arterial system; increase in volume in arterial vessels increases pressure; removal of blood from venous vessels results in decrease in venous pressure; pressure gradient is driving force between aorta and right ventricle |
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Term
| increases in central venous pressure |
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Definition
| this means more blood is added to venous side and this increase cardiac output (as dependent variable) |
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Term
| increae in cardiac output |
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Definition
| CVP decreases as a function of cardiac output with CVP as dependent variable |
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Term
| graph of cardiac function and vascular function |
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Definition
| when they are plotted there is a point at which they intersect and are at equilibrium at which the cardiovascular system will function |
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Term
| hypervolumia effect on CVP |
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Definition
| at any cardiac output the CVP will be higher and due to increase in CVP the cardiac output would increase |
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Term
| autotransfusion effect CVP vs CO |
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Definition
| when veins contract compliance decreases and elevates CVP and CO will increase |
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Term
| CVP vs CO effects in changes in peripheral resistance |
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Definition
| MCP not directly effected by arteriole contraction; but TPR increases so more pressure required to drive same cardiac output and more volume needs to be placed in arteries and CVP will decrease |
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Term
| changes in contractility effects on CVP vs CO |
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Definition
| increasing contractility will cause an increase in CO for any CVP and because more blood is transferred to arterial side CVP will decrease |
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Term
| CO vs CVP in failing heart |
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Definition
| as CO falls, CVP increases and this increases EDV and resting length of cardiac muscle and causes CO to be closer to normal and blood volume may increase in compensation |
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Term
| CO vs CVP in failing heart |
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Definition
| as CO falls, CVP increases and this increases EDV and resting length of cardiac muscle and causes CO to be closer to normal and blood volume may increase in compensation |
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Term
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Definition
| will increase pressure in all peripheral vessels and creates a greater pressure gradient between these and the heart increasing venous return |
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Term
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Definition
| stretch receptors located principally in walls of carotid sinus and aortic arch (glossopharyngeal nerve-carotid; afferent fibers of vagus-aortic arch); increasing arterial pressure increases number of afferent impulses going to CNS; works between 50-200mmHg |
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Term
| influence of baroreceptors on the CNS |
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Definition
| stimulates parasympathetic and inhibits sympathetic; decrease in BP results in periperal vasoconstriction and stimulation of the heart-contractility and HR; increase in BP will result in decrease in HR by parasympathetics |
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Term
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Definition
| located at bifurcation of pulmonary artery; increasing pulmonary arterial pressure relexly causes a decrease in systemic arterial pressure |
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Term
| cardiac stretch receptors |
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Definition
| atrial receptors sensitive to change in blood volume and can compensate through modulation of sympathetic casoconstriction fibers and AVP secretion |
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Term
| atrial natriuretic factor |
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Definition
| hormone released by myocardial cells may play a role in control of blood volume |
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Term
| body mechanisms that contribute to maintaining blood pressure |
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Definition
| 1. hormonal mechanisms; 2. physical mechanisms; 3. neuronal mechanisms |
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Term
| peripheral chemoreceptors |
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Definition
| situated in region of aortic arch and just medial to carotid sinus most sensitive to reduction in arterial oxygen; important in anoxia, asphyxia, or severe hemorrhage |
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Term
| hypothalamus control center |
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Definition
| contains both pressor and depressor areas; coordinates generalized cardiovascular responses (temperature regulation and defense reaction) |
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Term
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Definition
| can either evoke pressor or depressor responses |
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Term
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Definition
| emotional excitement causes increase in blood pressure and tachycardia |
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Term
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Definition
| fainting in response to emotional distress |
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Term
| cerebral ischemic response |
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Definition
| intense activation of the sympathetic nervous system in response to low arterial pressure |
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Term
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Definition
| cause pressor response (by painful stimulus on the body surface); or depressor response (distension of viscera) |
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Term
| effects of changes in posture |
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Definition
| changing from supine to vertical causes large increase in hydrostatic pressure in dependent limbs and decrease in return of blood to the heart and CVP |
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Term
| precapillary resistance vessels |
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Definition
| include small arteries, arterioles, and terminal arterioles and involved in regulation of TPR and local blood flow and regulate blood flow among the capillaries |
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Term
| postcapillary venous vessels |
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Definition
| include post-capillary venules, venules, and small veins; PC venules devoid of smooth muscle important area of exchange; alterations in resistance can significantly influence capillary hydrostatic pressure |
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Term
| magnitude of flow through microvascular bed |
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Definition
| controlled by alterations in the diameter of small arteries and arterioles |
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Term
| distribution of flow among the capillaries |
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Definition
| primarily determined by alterations in the diameter of the terminal arterioles and precapillary sphincters |
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Term
| effect of increasing number of capillaries perfused |
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Definition
| decreases intercapillary distances and contributes to increasing oxygen extraction from the blood |
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Term
| neural influence of arterial diameters |
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Definition
| primarily by innervation of sympathetic innervation; most pronounced effect on small arteries and arterioles; involved in regulation of systemic blood pressure; but little influence over terminal arterioles and precapillary sphincters |
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Term
| hormonal effect on diameter of arterial vessels |
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Definition
| vasoactive hormones affect the diameter |
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Term
| metabolic effects of diameters of arterial vessels |
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Definition
| byproducts of tissue metabolism can cause the vascular smooth muscle to relax and dilate; provides coupling mechanism between local tissue need and local blood flow |
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Term
| myogenic effects on diameter of arterial vessels |
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Definition
| degree of contraction of smooth muscle cells influenced by changes in transmural pressure; increasing transmural pressure causes the vessels to constrict and decreasing pressure causes them to dilate |
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Term
| short term autoregulation |
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Definition
| maintenance of a constant blood flow in the face of a changing perfusion pressure occurs because of metabolic and myogenic mechanisms w/ sympathetic nerves modulating the range of pressure over which it may occur |
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Term
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Definition
| refers to changes in vascular morphology over weeks and months in response to increased pressure |
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Term
| regulation of blood flow to the heart |
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Definition
| metabolic control mechanisms usually override the direct effects of autonomic nerves; changes in tissue pressure can influence myocardial blood flow |
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Term
| coronary collateral vessels |
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Definition
| can compensate for occlusion of larger coronary vessels but only when the occlusion occurs over long periods of time |
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Term
| regulation of cerebral blood flow |
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Definition
| sympathetic stimulation does not increase vascular resistance instead increases autoregulatory range on the high pressure side but does not change the low pressure side |
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Term
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Definition
| loss of whole blood, proportionally the same amount of red cells and plasma producing a reduction in blood volume |
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Term
| mechanisms that can cause hypovolemia |
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Definition
| 1. burns; 2. vomiting; 3. diarrhea; 4. hemorrhage; 5. excessive sweating |
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Term
| changes due to hypovolemia |
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Definition
| 1. CVP; 2. pressure gradient which causes venous return; 3. venous return; 4. right and left ventricular preload; 5. stroke volume; 6. cardiac output; 7. mean blood pressure |
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Term
| baroreceptor response to fall in MBP |
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Definition
| 1. afferent nerve activity from baroreceptors is decreased; 2. causes increase in neural activity of vasoconstrictor center |
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Term
| activation of vasoconstrictor center |
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Definition
| causes selective vasoconstriction of renal arterioles, cutaneous arterioles, and splanchnic arterioles |
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Term
| areas of vasodilation during hypovolemia |
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Definition
| cerebral and coronary arteries due to local control factors rather than neural control to maintain adequate blood flow |
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Term
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Definition
| occurs because of activation of vasoconstriction center; causes decreases in venous compliance and shift from veins to arteries to increase MBP, SV, and CO |
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Term
| other neural effects of hemorrhage |
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Definition
| 1. parasympathetic activity decreases and heart rate and CO increases; 2. sympathetic increases and HR and contractility increases; 3. adrenal medulla is stimulated and norepinephrine and epinephrine are released into blood |
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Term
| hemorrhage effects of capillary filtration and absorption |
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Definition
| 1. capillary hydrostatic pressure is decreasing to decrease rate of filtration; 2. rate of absorption will increase as fluid shifts into cardiovascular system, blood volume increased, hematocrit is decreased and blood viscosity is decreased |
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Term
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Definition
| involves motion of the limbs, little force generated and delivery of oxygen to muscle which is adequate to meet demands |
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Term
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Definition
| incvolves little limb motion, high force generation, and delivery of oxygen to muscle is not adequate to meet the oxygen demand |
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Term
| intensity of exercise measurements |
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Definition
| 1. workload can be measured in watts (absolute); 2. relative workload % of max workload (that required to reach max O2 consumption); 3. METs (multiples of resting oxygen consumption); 4. HR because of linear relationship with intensities |
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Term
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Definition
| maximum oxygen consumption best measure of aerobic fitness determined by gender, level of training, age, and genetic factors |
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Term
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Definition
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Term
| effects of exercise on the heart and cardiac output |
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Definition
| 1. BP increases; 2. SV increases; 3. CO increases; 4. HR increases; 5. arterial-venous O2 difference increases |
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Term
| heart rate increase during exercise |
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Definition
| increase is proportional to workload, estimation is 220-age; produced by increase in sympathetics, decrease in parasympathetics, increases in catecholamines |
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Term
| stroke volume increases during exercise |
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Definition
| caused by increase in ventricular contractility; but EDV does not change very much |
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Term
| cardiac output increases during exercise |
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Definition
| because SV may increase two fold; HR may increase 3 fold; so CO may increase 6 fold |
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Term
| oxygen extraction changes during exercise |
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Definition
| amount of oxygen in arterial blood does not change during exercise but amount of oxygen in mixed venous blood decreases (drawn from right ventricle or pulmonary artery) greater the intensity the lower the oxygen content |
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Term
| total peripheral resistance decreases during exercise |
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Definition
| arterioles perfusing muscles are dilated by metabolic byproducts; blood flow to muscles increases and number of capillaries through which blood flows is increased |
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Term
| effect of exercise on coronary arterioles |
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Definition
| dilate to increase coronary blood flow and heart metabolizes aerobically and need to dilate to get more blood flow to the heart |
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Term
| effect of exercise on cutaneous blood flow |
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Definition
| the blood vessels dilate; resistance of arterioles perfusing the skin dcreases and flow increases and contributes to dissipation of heat produced by the exercising muscles |
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Term
| resistance of arterioles of non-exercising muscle during exercise |
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Definition
| arteriole resistance increases to reduce blood flow to these tissues |
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Term
| venous vessels during exercise |
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Definition
| contract and shifts blood from the veins into the heart; EDV may not increase because ventricular filling time may decrease; augmented by contraction of skeletal muscle which squeezes blood out of the tissue |
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Term
| effects of exercise on blood pressure |
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Definition
| 1. MBP increases; 2. systolic pressure increases; 3. diastolic pressure decreases; 4. pulse pressure increases |
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Term
| effect of long-term training at rest |
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Definition
| 1. reduced HR due to changes in nerve activity; 2. increased EDV because of longer ventricular filling time; 3. increased SV and blood volume; 4. resting CO remains unchanged; 5. increased capillary density in trained skeletal muscles |
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Term
| submaximal workload effect after long term training |
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Definition
| 1. reduced heart rate; 2. increased SV; 3. greater oxygen extraction by muscles; 4. reduced blood flow to trained muscles; 5. decreased perceived effert; 6. increased time until exhaustion; 7. decreased level of sympathetic nerve activation |
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Term
| effects of long-term training on maximal workload |
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Definition
| increased max SV, CO; decreased max HR; increased max oxygen extraction and consumption |
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Term
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Definition
| when intensity, duration, or frequency of training are decreased the max oxygen consumption decreases rapidly |
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Term
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Definition
| volume of blood transmitted in certain period of time |
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Term
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Definition
| distance a specific component of the blood moves within a certain period of time |
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Term
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Definition
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Term
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Definition
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Term
| determinants of resistance |
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Definition
| R=(8*l*viscosity)/(pi*r^4) |
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Term
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Definition
| RBC and other elements move in linear fashion |
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Term
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Definition
| random component to flow path |
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Term
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Definition
| predicts type of flow, greater than 2000 is turbulent; and less than 1000 is laminar |
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