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| purkinje fibers |
-at apex fo heart
-transmit signals up
-pumps up b/c blood has to go out on top |
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mcs5109 Mon, 20 Oct 2008 05:33:41 GMT |
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| bundle fo His |
-frfom AV node to bottom of heart |
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mcs5109 Mon, 20 Oct 2008 05:33:41 GMT |
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| av NODE |
-group of auto cells near bottom of right atrium
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mcs5109 Mon, 20 Oct 2008 05:33:41 GMT |
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| atria |
...innsulated from ventricles via connective tissue rings so electrical signal can't transfer into ventricles |
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mcs5109 Mon, 20 Oct 2008 05:33:41 GMT |
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| SA node |
-where depolarization begins
-autorhymic cells in right atrium
-main pacemaker
-spread rapidly via noncontractile autorhythmic fibers |
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mcs5109 Mon, 20 Oct 2008 05:33:41 GMT |
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| slow response |
-higher RMP (-70 to 10mV)
-no plateau
-unstable RMP
-pacemaker tissue
phase 0:
-net Na+ comes in and slowly depolarizes
-tetrodoxin has no effect
-only some K+ efflux
Phase 3:
-voltage-gated Ca++ rushes into cell at threshold
-Ca+ rushes in
-Ca++ gates close at top
Phase 4: decrease in Ca++ influx
-K+ efflux
-NAKATPase pumo
-leaky |
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mcs5109 Mon, 20 Oct 2008 05:26:22 GMT |
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| plateau phase |
-in fast repsonse tissue
-Ca++ voltage gated
-slow Ca++ influx balanced by K+ influx
-important to fill w/ blood
-phase 2 |
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mcs5109 Mon, 20 Oct 2008 05:17:38 GMT |
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| fast response |
-atria and ventricle cells
-5 phases
--90 to +30
-2Na+ gets: M (activation) and H (deactivation)
Phase 0:
-wave of depolarization
-Na+ voltage-gated channels open (M and H opened)
-rapid Na+ influx
-tetrodoxin poisons this channel
Phase 1:
-Na+ channels close (H gate)
-initial repolarization
-K+ goes out
Phase2:
-plateau phase
-Ca++ voltage gated
-slow Ca++ influx balanced by K+ influx
Phase 3:
-final repolarization
-closure of Ca++ channels
-large efflux of K+ into cell
Phase 4:
-stabilize RMP at -90mV via NaKATPase pump
-effective/relative refractory period |
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mcs5109 Mon, 20 Oct 2008 05:17:38 GMT |
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| cardiac aschemia |
-Cardiac ischemia occurs when blood flow to the heart muscle (myocardium) is decreased by a partial or complete blockage of a coronary artery. |
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mcs5109 Mon, 20 Oct 2008 05:17:38 GMT |
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| depolarization of cardiac muscle cells |
-fast response (atria, ventricles)
-slow response (AV node, SA node) (susceptible to cardiac aschemia) |
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mcs5109 Mon, 20 Oct 2008 05:17:38 GMT |
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| -functional syncitium |
-thin membrane b/w cells
-stimulate one, all contract
-atria= faster autorhythmicity (70/min)
-ventricles= slower (20/min)
-if contraction breaks down, fibrillation occurs and death |
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mcs5109 Mon, 20 Oct 2008 05:17:38 GMT |
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| autorhythmicity |
-autodepolarization or self-excitable
-generate APs regardless of CNS
-from unstable RMP at -60mV
-though, never really "rests" at RMP |
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mcs5109 Tue, 21 Oct 2008 23:25:48 GMT |
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| cardiac muscle |
-distinct cells
-striated
-contractile elements
-intercalated disks= glue
-branched fibers= twist
autorhythmicity
-functional syncitium |
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mcs5109 Mon, 20 Oct 2008 05:17:38 GMT |
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| endocardium |
-innermost layer of tissue that lines the chambers of the heart |
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mcs5109 Mon, 20 Oct 2008 04:45:27 GMT |
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| myocardium |
-specifically the myocardium where they are also known as cardiac myocyte |
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mcs5109 Mon, 20 Oct 2008 04:45:27 GMT |
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| epicardium |
the outer layer of heart tissue |
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mcs5109 Mon, 20 Oct 2008 04:45:27 GMT |
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| heart wall |
-epicardium (visceral pericardium)
-myocardium
-endocardium |
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mcs5109 Mon, 20 Oct 2008 04:45:27 GMT |
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| mediastinal cavity |
-It is the central compartment of the thoracic cavity |
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mcs5109 Mon, 20 Oct 2008 04:45:27 GMT |
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| pericardial sac |
-where heart is located
-membraneous |
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mcs5109 Mon, 20 Oct 2008 04:45:27 GMT |
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