Autorhytmic cell and electric conduction Flashcards
2 main types of cardiac cells
- autorhythmic
2. myocytes
which cells of intrinsic conduction system can gen. a spontaneous signal
all can, just at different rates
path of intr. conducting system
SA>internodal pathway>AV>his>purk>ventricle
2 functions of autocells
- pacemaker
2. rapid e transmission
functions of myocytes
- pump action
what are 2 stages of auto action potential
- pacemaker potential (slow creep)
2. action potential
at what mV does pacemaker hit action
-40mV
what happens at -40mV
funny channels close, some L-channels open and Ca rushes in
what channels open at beginning of pacemaker potential
funny channels If
what happens at top of action potential
Ca close, K open
what happens at point of hyperpolarization
K close, funny open
what does cAMP do to a funny channel
allows it to opon at different potential and be affected by auto system
what is a funny channel
HCN4 channel structure that allows passage of both Na and K
what are the 3 criteria for efficient cardiac funct.
- atria cont. should be complete before vent starts
- exit. of cardiac muscle fibers should be coordinated
- pairs of atria and vent. should be functionally coordinated
what is role of ECM network around cardiac mnuscle
controls electrical conduction so doesn’t spread
what does AV node do?
slows down rate of conduction
why are firing rates faster in SA than other sites
is SA node dies, will allow Av node to take over as the pacemaker
