Study BIOL 472 Topic 8 Flash Cards

 
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BIOL 472 Topic 8

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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
purkinje fibers
-at apex fo heart
-transmit signals up
-pumps up b/c blood has to go out on top
bundle fo His
-frfom AV node to bottom of heart
av NODE
-group of auto cells near bottom of right atrium
-
atria
...innsulated from ventricles via connective tissue rings so electrical signal can't transfer into ventricles
SA node
-where depolarization begins
-autorhymic cells in right atrium
-main pacemaker
-spread rapidly via noncontractile autorhythmic fibers
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
plateau phase
-in fast repsonse tissue
-Ca++ voltage gated
-slow Ca++ influx balanced by K+ influx
-important to fill w/ blood
-phase 2
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
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.
depolarization of cardiac muscle cells
-fast response (atria, ventricles)
-slow response (AV node, SA node) (susceptible to cardiac aschemia)
-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
cardiac muscle
-distinct cells
-striated
-contractile elements
-intercalated disks= glue
-branched fibers= twist
autorhythmicity
-functional syncitium
endocardium
-innermost layer of tissue that lines the chambers of the heart
myocardium
-specifically the myocardium where they are also known as cardiac myocyte
epicardium
the outer layer of heart tissue
heart wall
-epicardium (visceral pericardium)
-myocardium
-endocardium
mediastinal cavity
-It is the central compartment of the thoracic cavity
pericardial sac
-where heart is located
-membraneous
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