Lecture 6- System overview and the heart Flashcards
Flow=
change in pressure/resistance
Resistance can be changed by changing … or change…
which has a greater effect?
viscosity
radius of lumen
radius
if you double the raidus, then resistance will drop…. fold
16
cardiac muscle is different from skeletal because it is branched and electrically coupled through … located in …
gap junctions
intercalated discs
The parasympathetic system ONLY innervates the… of the heart through … nerves.
The receptors are …. and the neurotransmitter is…
atria
vagus
muscarinic
acetylcholine
The sympathetic system innervate BOTH the … and … through …. receptors and the neurotransmitter…
atria
ventricles
beta-adrenergic
norepinephrine
The heart is also regulated hormonally by … from the blood
epinephrine
the … is the hearts pacemaker because it initiates each wave of excitation with atrial contraction
SA node
the only way that the atria and ventricles can electrically talk is through the ….
AV node
AP of ventricular cell:
The rapid opening of …. channels is responsible for the rapid depolarization phase
voltage gated channels (Na influx)
AP of ventricular cell:
The prolonged “plateau” depolarization is due to the slow but prolonged opening of…. channels PLUS closure of …. channels
voltage gated Calcium channels (Ca enters)
K channels (K exits)
AP of ventricular cell:
Opening of… results in the repolarization phase
K channels
The AP of a myocardial ventricular cell has a true….
The AP of an SA nodal cell does NOT have a true…
resting membrane potential
AP of an autorhythmic nodal cell:
Na ions leaking in through … channels PLUS … ions moving in through the T calcium channels cause a threshold graded depolarization
F-type (funny)
Calcium
AP of an autorhythmic nodal cell:
The rapid opening of … is responsible for the rapid depolarization phase
voltage gated calcium channels
