Autorhytmic cell and electric conduction

Question 1

2 main types of cardiac cells

Answer 1

1. autorhythmic

2. myocytes

Question 2

which cells of intrinsic conduction system can gen. a spontaneous signal

Answer 2

all can, just at different rates

Question 3

path of intr. conducting system

Answer 3

SA>internodal pathway>AV>his>purk>ventricle

Question 4

2 functions of autocells

Answer 4

1. pacemaker

2. rapid e transmission

Question 5

functions of myocytes

Answer 5

1. pump action

Question 6

what are 2 stages of auto action potential

Answer 6

1. pacemaker potential (slow creep)

2. action potential

Question 7

at what mV does pacemaker hit action

Answer 7

-40mV

Question 8

what happens at -40mV

Answer 8

funny channels close, some L-channels open and Ca rushes in

Question 9

what channels open at beginning of pacemaker potential

Answer 9

funny channels If

Question 10

what happens at top of action potential

Answer 10

Ca close, K open

Question 11

what happens at point of hyperpolarization

Answer 11

K close, funny open

Question 12

what does cAMP do to a funny channel

Answer 12

allows it to opon at different potential and be affected by auto system

Question 13

what is a funny channel

Answer 13

HCN4 channel structure that allows passage of both Na and K

Question 14

what are the 3 criteria for efficient cardiac funct.

Answer 14

1. atria cont. should be complete before vent starts
2. exit. of cardiac muscle fibers should be coordinated
3. pairs of atria and vent. should be functionally coordinated

Question 15

what is role of ECM network around cardiac mnuscle

Answer 15

controls electrical conduction so doesn’t spread

Question 16

what does AV node do?

Answer 16

slows down rate of conduction

Question 17

why are firing rates faster in SA than other sites

Answer 17

is SA node dies, will allow Av node to take over as the pacemaker