Term
| components of the cardiovascular system |
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Definition
| 1. blood vascular system (heart, arteries, capillaries, veins); 2. lymphatic vascular system-begin as blind capillaries and join to form larger vessels, terminate in blood vascular system) |
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Term
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Definition
| 1. tunica intima; 2. tunica media; 3. tunica adventitia |
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Term
| components of tunica intima |
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Definition
| endothelial cells supported by basal lamina, few smooth muscle cells, loose CT, internal elastic lamina |
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Term
| components of tunica media |
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Definition
| concentric layers of smooth muscle cells (connected by gap junctions), collagen type II, proteoglycans, glycoproteins, elastic fibers, and external elastic lamina |
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Term
| components of tunica adventitia |
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Definition
| collagen type I and elastic fibers, vasa vasorum, unmyelinated sympathetic nerve fibers |
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Term
| ways to form blood vessel |
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Definition
| 1. vasculogenesis; 2. angiogenesis |
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Term
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Definition
| de novo vessel formation by coalescense of free migrating angioblasts during embryogenesis |
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Term
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Definition
| sprouting and bridging from existing vessels during embryogenesis and in the adult |
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Term
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Definition
| secreted by mesenchymal cells regulate proliferation of endothelial precursor cells |
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Term
| mechanism of angiogenesis |
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Definition
| ECs migrate, proliferate and assemble into tubes and periendothelial cells recruited to surround the tubes by Ang1 |
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Term
| blood pressure in capillaries |
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Definition
| about 35mmHg at arterial end and about 10mmHg at venous end |
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Term
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Definition
| conduct blood from the heart to medium sized arteries (pulmonary arteries, brachiocephalic, common carotids, aorta, etc.) |
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Term
| tunica intima of elastic arteries |
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Definition
| 1. lined by endothelium and CT and smooth muscle cells that synthesize and secrete collagen and elastic fibers; 2. endothelial cells joined by tight junctions; 3. internal elastic membrane not obvious; 4. endothelial cells synthesize substances like coagulating factor, anti-coagulants and endothelin |
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Term
| media of elastic arteries |
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Definition
| 1. thickest layer made up of smooth muscle cells joined by gap junctions surrounded by basal lamina; 2. elastic fibers are arranged in concentric, fenestrated layers help move column of blood away from heart and maintain blood pressure |
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Term
| adventitia of elastic arteries |
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Definition
| thin layer of CT comprised of collagen and elastic fibers, fibroblasts and macrophages (and vasa vasorum and nerves) |
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Term
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Definition
| weakening of wall of artery due to degradation of elastin within the tunica media |
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Term
| vascular occlusive disease |
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Definition
| dedifferentiation of endothelial cells or smooth muscle cells when stimulated by vessel growth or injury |
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Term
| characteristics of muscular arteries |
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Definition
| 1. internal elastic membran if intima is readily seen; 2. media is quite thick and made up of spirally arranged smooth muscle cells that produce collagen and elastin; 3. tunica adventitia is relatively thicker compared to media consists of collagen, fibroblasts and elastic fibers |
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Term
| distinguishing small arteries and arterioles |
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Definition
| small arteries have about 8 layers of smooth muscle cells in media and arterioles have about two layers |
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Term
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Definition
| wide enough for single RBC consist of single layer of endothelial cell and its basal lamina |
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Term
| molecules syntesized by endothelial cells |
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Definition
| prostaglandin I2, plasminogin activator, IL-1, growth factors, etc. |
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Term
|
Definition
| have endothelial cells connected by occluding junctions, pericytes enclosed in basal lamina may be present (occur in muscle, lung, and CNS) |
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Term
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Definition
| have channels in capillary wall that 80-100 nm in diameter; occur in endocrine glands and tissues, intestinal tract, and gall bladder |
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Term
| discontinuous capillaries |
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Definition
| aka sinusoids have gaps between endothelial cells and incomplete basal lamina underlying endothelium (liver, spleen, and bone marrow) |
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Term
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Definition
| arteriovenous shunts which can pass blood directly from arterioles to venules and veins |
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Term
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Definition
| transport blood back to the heart, have larger lumens and less well defined tunics; have valves to ensure unidirectional blood flow; more collagen than elastin and less smooth muscle; large veins have longitudinally arranged bundles of smooth muscle in tunica adventitia |
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Term
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Definition
| arteries open in capillaries that collect into veins that drain into capillaries (sinusoids) |
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Term
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Definition
| arteriole supplies capillaries which drain into second arteriole which opens into another capillary network |
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Term
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Definition
| run adjacent to blood vessels and collect fluid from tissue spaces; very thin walled, and have valves and are uni-directional |
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Term
| characteristics of lymphatic capillaries |
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Definition
| 1. blind ending and converges with other capillaries; 2. extremely permeable and attenuated or absent basal lamina; 3. vessels branch extensively and filters through lymph nodes |
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Term
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Definition
| has mesothelial cells on its outer surface rest on thin layer of CT; visceral layer of pericardium and faces percardial cavity; beneath is loose CT which contains adipose tissue and houses blood vessels and nerves that supply the heart |
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Term
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Definition
| lies below epicardium containing cardiac myocytes; contains many blood vessels, CT components, and nerves |
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Term
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Definition
| 1. has layer of CT, subendocardium, continous with CT of myocardium; 2. intermediate layer of CT and smooth muscle; 3. inner endothelial layer that faces the lumen of the heart chambers |
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Term
| cardiac conduction system |
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Definition
| initiated in SA node spreads to cells of atrium to the AV node conducted rapidly to ventricles by bundle of His then to Purkinje fibers ending on cardiac myocytes |
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Term
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Definition
| cardiac myocytes' response to overload to ensure cardiac output is close to normal |
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Term
| action potential of heart |
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Definition
| follows pattern established suring cardiac development where goes SA to A to V to TA |
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Term
| regulation of ion channels |
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Definition
| 1. membrane potential; 2. phosphorylation reactions; 3. binding of molecules to specific sites on external surface |
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Term
| resting potential (phase 4) ion channels |
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Definition
| 1. majority that are open are K selective; 2. inward rectifier K channel (Iki) is predominant channel open at rest to maintain resting potential; 3. this channel closes when membrane depolarizes so it can stay depolarized longer |
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Term
| steps in upstroke (phase 0) |
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Definition
| 1.depolarization of resting potential causes voltage sensitive Na channels to open; 2. Na channels open and close rapidly causing a rapid depolarization and activation of other ion channels |
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Term
| early repolarization (phase 1) |
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Definition
| 1. activation of transient outward K channel (Ito) causes early partial repolarization; 2. L-type Ca channels are also opening during this phase-causes excitation-contraction coupling |
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Term
|
Definition
| 1. Ca channels are inactivating and delayed rectifier K channels are activating (Iks and Ikr); 2. responsible for the long refractory period of cardiac myocytes |
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Term
| final repolarization (phase 3) |
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Definition
| 1. caused by activation of delyaed rectifier K channels; 2. defects in these channels slow rate of inactivation prolong duration of AP |
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Term
| action potential in atrial myocardium |
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Definition
| 1. AP duration is shorter than in ventricle; 2. have K+ channels that are regulated by ACh and Kv1.5 channels (unique to use in drug therapy) |
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Term
|
Definition
| cells depolarize spontaneously to induce action potentials |
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Term
| SA node phase 4 depolarization |
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Definition
| results from reducing outward currents and increasing inward currents; 1. funny channel current (allows Na to permeate); 2. Na/Ca exchanger current (spontaneous Ca release from SR); 3. T-type Ca current; 4. L-type Ca current |
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Term
| SA node upstroke and repolarization |
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Definition
| L type Ca channels cause upstroke and rectifier K channels cause repolarization |
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Term
| autonomic regulation of SA node |
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Definition
| 1.sympathetic neurotransmitters increase heart rate by incresing phase 4 depolarization; 2. parasympathetic neurotransmitters slow the heart rate |
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Term
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Definition
| connection between atria and ventricles; have less well polarized resting potential and slowly conducting action potentials; regulated by autonomic nerves; rely on Ca channels for action potentials |
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Term
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Definition
| disturbances of cardiac electrical activity includes spontaneous abnormal activity or reentrant arrhythmias |
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Term
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Definition
| requires anatomical condition where two parallel pathways for the AP to travel to a common location and one arm must exhibit unidirectional block produces an extra heartbeat |
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Term
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Definition
| the AP causes contraction by increasing cytosolic free calcium; causing calcium to bind to troponin C and allows actin and myosin interaction |
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Term
| calcium release in skeletal muscle |
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Definition
| Ca stored in SR and releases amount of Ca with each twitch sufficient to saturate TnC and cause maximal contraction |
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Term
| calcium release in cardiac myocytes |
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Definition
| SR stores and releases a variable amount of Ca with heart beat; that which is released is not enough to activate all of the contractile apparatus; Ca release is physiologically regulated |
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Term
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Definition
| increase and decrease in cytosolic free Ca; changes in this are responsible for changing the strength of contraction and amount of blood eject from ventricle |
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Term
| skeletal muscle sources of activor Ca |
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Definition
| only source is derived from SR |
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Term
| cardiac ventricular myocyte sources of activator Ca |
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Definition
| 1. about 75% comes from SR; 2. rest comes from extracellular space during the AP |
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Term
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Definition
| Ca-buffering molecule where most of the Ca is bound in the junctional SR |
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Term
|
Definition
| major sites where Ca is released and usually found in close apposition to the T-tubules |
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Term
|
Definition
| 1. influx of Ca through voltage activated L type Ca channels triggers the release of Ca from SR; 2. release process is graded through whole cell varying the number of SR junctions that release their Ca; 3. number of junctions determined by size of L-type Ca current; 4. amount released depends on the amount of Ca stored |
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Term
| depolarization induced Ca release |
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Definition
| mechanism that produces SR Ca release in skeletal muscle; direct physical link between voltage sensor in T-tubule and Ca release channel in junctional SR (not present in cardiac cells) |
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Term
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Definition
| enters the cell during AP and can 1. induce SR Ca release; 2. elevate cytosolic free Ca to activate contraction; 3. source of Ca to fill the SR Ca Stores |
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Term
| voltage dependent L-type Ca channels |
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Definition
| principle route for Ca influx in ventricular myocytes; Ca influx elevates concentration and causes it to bind to RYR receptor causing it to open resulting in Ca efflux from the SR |
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Term
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Definition
| minor route of Ca influx during AP; depolarization causes reversal of it and Ca is moved into the cell; acts as important source to load Ca for the SR |
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Term
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Definition
| ATP-comsuming transporter (SRCaATPase or SERCa) regulated by phospholamban |
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Term
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Definition
| associates with SERCa to inhibit it; has PKA and CAM KII dependent phosphorylation which removes the inhibition |
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Term
|
Definition
| foward mode NCX is major mechanism to remove Ca that entered by Ltype Ca channels and reverse mode NCX |
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Term
| norepinephrine effect of Ca transient |
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Definition
| 1. binds to beta-adrenergic receptors and elevates cAMP and PKA; 2. PKA phosphorylates ltype Ca channels, RYR, PBL, and TnC |
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Term
| phosphorylation of L-type Ca channel |
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Definition
| causes more channels to open during the AP; increase Ca current increasing cytoplasmic Ca |
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Term
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Definition
| reduces its Ca binding affinity and Ca comes off at a faster rate and increases rate of relaxation |
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Term
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Definition
| increases its Ca binding affinity which leads to enhanced SR Ca release |
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Term
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Definition
| causes an increase in magnitude of contraction; increases time averaged Ca influx |
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Term
| factors determining strength and speed of contraction |
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Definition
| 1. % of muscle cells that are activated (not important in cardiac cells b/c every heart cell is activated); 2. resting muscle length (preload) determines actin-myosin overlap; 3. magnitude of active state (Ca transient) or contractility; 4. changes in duration of active state-contractions cannot be summated |
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Term
| isometric contraction in cardiac muscle |
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Definition
| where muscle develops force but prevented from shortening determined by resting muscle length and contractility |
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Term
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Definition
| increases muscles ability to develop force; relationship usually called the Starling relationship |
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Term
| stretching resting cardiac muscle |
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Definition
| significantly stiffer than skeletal muscle; greater forces are required to stretch as muscle length increases; very difficult to stretch cardiac muscle beyond sarcomere length of 2.2 microns (protective mechanism for heart) |
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Term
| increased stiffness of cardiac myocytes |
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Definition
| 1. cytoskeleton (titin); 2. ECM (collagen); 3. pericardium prevent excess stretch |
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Term
| cardiac function and length-tension relationship |
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Definition
| ventricular filling increases-the force generating capacity of muscle increases, causing increased amount of blood to be ejected from the heart |
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Term
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Definition
| factors that increase Ca during the active state and shift the length-active tension relationship upward so greater force is developed at every preload |
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Term
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Definition
| factors that decrease Ca during the active state; cause developed force to decrease (parasympathetics) most usually regulated by varying sympathetic nerve activity |
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Term
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Definition
| reduced myofilament Ca binding caused by ischemia-reperfusion injury |
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Term
| maximal rate of contraction |
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Definition
| occurs when afterload=0 inotropic agents change the maximal rate while changing the preload does not |
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Term
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Definition
| is comparable to muscle length and is equal to the largest volume of the heart |
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Term
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Definition
| as end diastolic volume increases the sarcomeres are stretched and develop more force to cause an increase |
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Term
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Definition
| plot of the instantaneous pressures and volumes with volume on the x-axis and pressure plotted on the y-axis |
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Term
| corners of pressure volume loop |
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Definition
| each represent an event during cardiac cycle; 1. lower right (mitral valve closing); 2. upper right (aortic valve opening); 3. upper left (aortic valve closure); 4. lower left (mitral valve opening) |
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Term
| sides of pressure-volume loop |
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Definition
| each represents a phase of cardiac cycle; 1. right side=isovolumic contraction; 2. top=ventricular ejection; 3. left=isovolumic relaxation; 4. bottom=ventricular filling |
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Term
| width of pressure-volume loop |
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Definition
| represents the stroke volume |
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Term
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Definition
| represents the stroke work; work performed by left ventricle during one heart cycle |
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Term
| diastolic pressure-volume relationship |
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Definition
| relationship between ventricular pressure and volume measured when myocardium relaxed during filling; determined by diastolic ventricular compliance |
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Term
| diastolic ventricular compliance |
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Definition
| equals change in volume over change in pressure |
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Term
| decrease in ventricular compliance and PVR |
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Definition
| causes and upward shift in the diastolic PVR; resulting in a higher diastolic pressure at any volume |
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Term
| factors decreasing diastolic ventricular compliance |
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Definition
| 1. scar tissue within the heart walls; 2. calcified pericardium could both decrease compliance |
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Term
| end -systolic pressure-volume relationship (ESPVR) |
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Definition
| represents the maximum pressure that the ventricle can develop at any volume assuming contractility is constant |
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Term
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Definition
| found by allowing the ventricle to contract; but not eject blood at different end diastolic volumes |
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Term
| why does ventricular ejection end when upper left corner of P-V loop must end at ESPVR? |
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Definition
| Because if the ventricular volume was to decrease further the ventricle would not be able to produce enough pressure to over come aortic pressure |
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Term
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Definition
| represents afterload and is closely related to the mean blood pressure |
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Term
| afterload can be assessed by what factors |
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Definition
| 1. diastolic pressure (lowest pressure that occurs in aorta); 2. peak systlic left ventricular pressure; 3. average left ventricular pressure during ejection; 4. systolic wall stress |
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Term
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Definition
| best represented by the end-diastolic volume; measured in lower right corner of loop; can be inferred by changes in end-diastolic pressure |
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Term
| result of increase in preload (EDV) |
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Definition
| results in an increase in stroke volume (increases width of PV loop) |
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Term
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Definition
| intrinsic capability of a normal heart to change its stroke volume in response to changes in preload |
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Term
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Definition
| where the Frank-Starling mechanism is plotted by plotting preload (EDV) on the x-axis and stroke volume on the y-axis |
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Term
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Definition
| heart normally operates on the middle of the Starling curve and position of the curve can change |
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Term
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Definition
| only occurs transiently if there is a difference between blood flow into and out of the ventricle; will increase if ventricular filling is greater than rate of ventricular emptying; rate of ventricular emptying is less than the rate of filling the EDV will increase |
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Term
| factors ventricular filling is dependent on |
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Definition
| 1. ventricular compliance-increases; 2. increase in heart rate-decreases; 3. increase in venous pressure-increases; 4. increases in atrial contractility-increase ventricular filling |
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Term
| systolic ventricular wall stress |
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Definition
| measures afterload equals S=(P*r)/(2*Th); where P= left ventricular pressure; S=Stress; r=radius of ventricular chamber; Th=left ventricular wall thickness |
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Term
| different definitions of wall stress |
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Definition
| 1. force per unit area within the myocardium during ejection; 2. force which must be overcome for a sarcomere to shorten; 3. usually decreases during ejection |
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Term
| increased afterload reasons |
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Definition
| 1. patients with hypertension; 2. patients in heart failure because ventricle is dilated |
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Term
| afterload increased and preload and contractility held constant |
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Definition
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|
Term
| indices to measure contractility |
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Definition
| 1. ejection fraction; 2. Emax, the slope of the end-systolic pressure volume relationship; 3. maximum rate of change of left ventricular pressure during IVC |
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Term
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Definition
| controlled via sympathetic and parasympathetic nervous systems; sym will increase norepinenphrine concentration near SA node; decreased will decrese concentration ACh near SA node action potentials will increase |
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Term
| heart rate and cardiac output |
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Definition
| 1. if increased due to electrical pacing or arrhythmia the time for ventricular filling can be reduced to reduce SV, CO and BP; 2. excercise intensity increases, heart rate and contractility will increase so cardiac output will increase |
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Term
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Definition
| 1. left ventricular work per heart beat; SW=MSLVP*SV where MSLVP is the pressure against which the stroke volume must be ejected |
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Term
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Definition
| ratio of SW to the energy consumption of the ventricle (SW)/(Energy Consumption); decreasing efficiency will increase consumption |
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Term
| ventricular energy consumption |
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Definition
| closely related to myocardial oxygen consumption; increases due to 1. increases in stroke work; 2. increases in wall stress; 3. increases in Ca transport |
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Term
| occurence of myocardial ischemia |
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Definition
| happens when myocardial oxygen supply does not match myocardial oxygen demand |
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Term
| ventricular efficiency in heart failure |
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Definition
| it is low because ventricle is dialted and has large radius, large wall stress, and large energy consumption |
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Term
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Definition
| syndrome characterized by inability for the heart to pump a cardiac output sufficient to meet the normal metabolic demand of tissues |
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Term
| result of contractility decreases in failing heart |
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Definition
| reduces pressure generating capability of ventricle and ventricle dilates; increases EDV and EDP and increased EDP reflected back into pulmonary and systemic capillaries causing edema |
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Term
| cardiac compensatory mechanisms in failing heart |
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Definition
| 1. high level of sympathetic nerve activity; 2. sympathetic regulation is abnormal because of down regulation of beta-adrenergic signaling; 3. blood volume increase due to inadequate perfusion of kidneys |
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Term
| systolic stress on the heart |
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Definition
| myocytes increase number of sarcomeres arranged in parallel and myocytes widen and number of force bearing units increases |
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Term
| diastolic stress increases |
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Definition
| cells increase the number of sarcomeres arranged in series normalizing resting sarcomere length |
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Term
|
Definition
| spontaneously generate action potentials on their own at a rate if 110-120 beats per minute |
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Term
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Definition
| produces action potentials at a greater rate than any other pacemakers because it will depolarize other cells in the heart before they can generate an action potential |
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Term
| atrial electrical activation |
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Definition
| starts at SA node then depolarizes right atrium first and then left atrium and this causes the contraction (right atrium contracts prior to left atrium) |
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Term
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Definition
| only pathway between atria and ventricles and the speed of conduction slows down because body of AV node is small in diameter |
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Term
| parasympathetic innervation of AV node |
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Definition
| it is richly innervated by the AV node; ACh increases membrane K+ conductance and moves membrane to a more negative value |
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Term
| importance of AV node time delay |
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Definition
| gives the atria time to fill the ventricles with blood (about 20% of blood in ventricles comes from atrial contraction) |
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Term
| long refractory period of the AV node |
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Definition
| will filter out some of the action potentials in pathology such as atrial fibrillation |
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Term
| ventricular conduction system |
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Definition
| high velocity delivers action potential almost simultaneously to entire ventricular muscle to contract synchronously |
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Term
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Definition
| 1. right bundle-delivers to left side of interventricular septum and right ventricle; 2. left bundle-delivers to left ventricle |
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Term
|
Definition
| specialized myocardial cells deliver action potential from bundle branches to myocardial cells |
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Term
| phase I of ventricular activation |
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Definition
| depolarization of middle third of interventicular septum |
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Term
| phase II of ventricular activation |
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Definition
| depolarization of left wall of ventricle (average mean direction of action potential is patients left and inferior) |
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Term
| phase III of venticular activation |
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Definition
| base of ventricles depolarize mean average points to the right and superior |
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Term
|
Definition
| absolute voltage right arm is subtracted from left arm |
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Term
|
Definition
| potential difference between left leg and right arm (sum of Leads I and II) |
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Term
|
Definition
| potential difference from subtracting left arm arm from left leg |
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Term
| unipolar or augmented leads |
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Definition
| give views in addition to Leads I, II, and III |
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Term
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Definition
| represents the potential difference created when the right and then the left atrium depolarize |
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Term
|
Definition
| if right atrium is enlarged the P wave in some leads will increase; if have two peaks (bifid) may indicate left atrium is enlarged |
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Term
|
Definition
| if right atrium is enlarged the P wave in some leads will increase; if have two peaks (bifid) may indicate left atrium is enlarged |
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Term
|
Definition
| action potential propogates through the AV node, Bundle of His, bundle branches, and Purkinje fibers |
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Term
|
Definition
| duration between 0.12 and .2 seconds and under parasympathetic control; if greater than 0.2 seconds distinguished as first degree heart block |
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Term
|
Definition
| deplorarization of left and right ventricles; last less than 0.1 seconds |
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Term
|
Definition
| may result from bundle branch block or myocardial ischemia or ventricular hypertrophy |
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Term
|
Definition
| ventricles are fully depolarized if not on baseline may be sign of ischemia |
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Term
|
Definition
| repolarization of the left and right ventricles, spreads from epicardium to endocardium |
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Term
|
Definition
| pacemaker is in SA node and P wave is followed by QRS complex |
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Term
| nodal or junctional rhythm |
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Definition
| pacemaker develops in or near the AV node; action potential spreads simultaneously in two directions P wave would be in QRS complex or PR segment less than 0.12 seconds |
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Term
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Definition
| bizarre QRS complex not preceeded by P wave |
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Term
| time representation of EKG trace |
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Definition
| each mm (small block) is 0.4 sec and each dark line is 0.2 seconds |
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Term
|
Definition
| duration of single heart beat when 60 divided by this it results in heart rate |
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Term
|
Definition
| some intervals or heart rate are long others are short has normal PR intervals |
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Term
|
Definition
| R-R interval is very long reaching 1.4 seconds high vagal efferent activity |
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Term
|
Definition
| R-R intervals are short about 0.42 seconds heart rate above 100 beats/min |
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Term
|
Definition
| PR interval greater than 0.2 seconds from slow conduction through AV node |
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|
Term
| second degree heart block |
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Definition
| not all P waves are followed by QRS complexes; some P waves are blocked at AV node |
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Term
|
Definition
| P waves and QRS complexes occur at different rates may be caused by ischemia in AV node |
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Term
|
Definition
| increase in QRS complex may reduce pressure generating capability of affected ventricle |
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|
Term
|
Definition
| either multiple pacemakers or if action potential never dies out; may cause reduced ventricular filling ; also atrial appendaged no longer contract and blood stagnates and can embolize to other parts of the body |
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|
Term
|
Definition
| QRS complexes are bizarre none preceded by p wave reduces ventricular filling |
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|
Term
|
Definition
| no longer effective pumps and cardiac output drops to zero; defibrillation must be iniated to rescue the patient |
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Term
|
Definition
| first phase of systole; muscle begins to contract on the incompressible blood in the ventricle, mitral valve closes and intraventricular pressure increases and nears aortic pressure |
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Term
|
Definition
| intraventricular pressure increases over aortic pressure and opens the aortic valve |
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|
Term
| reversal of pressure gradient across aortic valve |
|
Definition
| aortic pressure becomes higher than ventricular pressure; blood flow eventually stops and moves retrograde position and causes aortic valve leaflets to close |
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|
Term
|
Definition
| volume remaining in ventricle once ejection has occurred; typical stroke volume is about 70ml |
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|
Term
|
Definition
| fraction of end diastolic volume that is ejected (SV/EDV) normal EF is .6 |
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|
Term
|
Definition
| equals SV times HR and typical CO at rest is 5L |
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|
Term
|
Definition
| where both mitral and aortic valves are closed ventricular myocardium is relaxing and intraventricular pressure is decreasing |
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|
Term
|
Definition
| occurs when ventricular pressure falls below atrial pressure; diastasis is slow ventricular filling |
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|
Term
|
Definition
| atrium contracts to fill ventricle further with extra 20-25% of blood |
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Term
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Definition
| produced by atrial contraction and creates rise in ventricular pressure (ventricular "a" wave) |
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Term
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Definition
| occurs during isovolumic contraction, produced by bulging of mitral valve |
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Term
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Definition
| occurs right after c wave and peaks at instant mitral valve opens caused by filling of atrium by pulmonary veins |
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Term
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Definition
| if valve offers abnormally high resistance to flow of blood |
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Term
| papillary muscles and chordinae tendinae |
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Definition
| apply tension of valve leaflets prevents valves from bulging too far into atria and preventing regurgitation |
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Term
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Definition
| occurs at beginning of isovolumic contraction, rapid rise in pressure causes mitral valve to vibrate; ends before beginning of ejection |
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Term
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Definition
| end of ejection (systole) retrograde blood flow pushes aortic valve into ventricle and it rebounds towards aorta; results in aortic incisura and this rapid pressure changes cause the second heart sound |
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Term
| physiological splitting of second heart sound |
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Definition
| during inspiration can distinguish between A2 and P2 because it causes right ventricle contraction to last longer |
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Term
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Definition
| narrowing of the valve which results in the vlve offering increases resistance to foward flow of blood |
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Term
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Definition
| inability of the valve to close and seal properly which results in a valvular regurgitation; flow of blood is in retrograde direction |
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Term
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Definition
| blood flows from high to low pressure; greater the pressure gradient the greater the flow; valves establish unidirectional flow |
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Term
| aortic/ventricle pressure difference during ejection |
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Definition
| blood flows through aortic valve because 2-3 mmHg pressure gradient exists during systole |
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Term
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Definition
| 1. when orifice CSA (aortic valve area) decreases to less than 50% of normal area; 2. occurs because cusps become less mobile or space taking lesion in the orifice |
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Term
| result of aortic stenosis |
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Definition
| the reduced AVA and increased valvular resistance increases left ventricular systolic pressure (while aortic pressure remains normal) |
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Term
| energy in higher pressure of aortic stenosis |
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Definition
| goes into velocity of blood as flows through aortic valve and energy lost to friction and turbulence and causes murmur |
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Term
| ejection murmur of aortic stenosis |
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Definition
| murmur occurs during ejection and varies in amplitude due to blood velocity in crescendo-decrescendo murmur; not right after first heart sound |
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Term
| effect of aortic stenosis on cardiac mechanics |
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Definition
| 1. increased afterload-increased MSLVP and increased wall stress (due to increased pressure); 2. stroke work will increase if MSLVP increases more than stroke volume increases; 3. increased afterload with no compensation will decrease SV, CO, and MBP |
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Term
| compensation mechanisms of aortic stenosis |
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Definition
| due to increased sympathetic nerve activity: 1. increased contractility; 2. increased heart rate; 3. increased TPR |
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Term
| long term effects of aortic valve stenosis |
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Definition
| 1. left ventricular hypertrophy-new sarcomeres are formed in parallel, to return forces back to normal and decrease wall stress; 2. cardiac remodeling-diastolic compliance decreases, coronary artery growth will not keep path with hypertrophy; 3. heart failure-decreased contractility, ventricular dilation, preload reserve decreases |
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Term
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Definition
| valve cusps do not seal properly upon closure; when the pressure gradient across the valve is negative valve permits blood flow in wrong direction |
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Term
| effects of aortic regurgitation on the cardiac cycle |
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Definition
| 1. diastolic aortic pressure is reduced because blood is flowing out of both ends; 2. systolic BP may increase due to large stroke volume; 3. pulse pressure is increased; 4. forward stroke volume is less than normal; 5. left atrial pressure will increase-pulmonary edema; 6. can occur in all phases which artial pressure is greater than ventricular pressure |
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Term
| aortic valve regurgitation murmur |
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Definition
| occurs in all phases which ventricular pressure is lower than aortic pressure; and can even occur during systole because of such a large flow of blood in ventricles |
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Term
| aortic valve regurgitation effects of ventricular mechanics |
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Definition
| 1. left ventricle is dilated; 2. increased wall stress; 3. left ventricle is hypertrophied (sarcomeres laid in series); 4. left ventricular compliance decreased; 5. intially preload and contractility increase |
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Term
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Definition
| mitral valve orifice is obstructed, commissures fuse, leaflets calcify and thicken, and chordae tendinae fuse |
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Term
| mitral stenosis changes to cardiac cycle |
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Definition
| 1. causes abnormally high resistance and pressure gradient across valve during ventricular filling; 2. left atrial pressure increases and left atrium hypertrophies + pulmonary arterial pressure increases; 3. may develop atrial fibrillation |
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Term
| effects of mitrial stenosis |
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Definition
| 1. decreased LVEDV; 2. CO will decrease; 3. right ventricle and right atrium can also hypertrophy; 4. ratio of ventilation to perfusion in lungs changes |
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Term
| mitral valve regurgitation changes to cardiac cycle |
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Definition
| 1. whenever pressure in left ventricle is higher than left atrial pressure blood can flow in retrograde direction; 2. forward stroke volume decreases; 3. murmur is holosystolic-throughout systole and IVR; 4. large atrial v waves; 5. high left atrial pressures and atrial fibrillation |
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Term
| effect of mitral regurgitation on ventricular mechanics |
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Definition
| 1. left ventricular volume overload; 2. increased myocardial oxygen consumption; 3. increased sympathetic nerve activation |
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Term
| anatomical defects of tetralogy of Fallot |
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Definition
| 1. ventricular septal defect; 2.overriding aorta; 3. pulmonary artery stenosis; 4. right ventricle hypertrophy |
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Term
| pathophysiology of tetralogy of Fallot |
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Definition
| shunt causes systemic hypoxemia and cyanosis |
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Term
| symptoms of tetralogy of Fallot |
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Definition
| 1. dyspnea on exertion or when crying; 2. tet spells-irritability, cyanosis, hyperventilation and sometimes syncope |
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