lect 31. action potential and cardiac muscles

Question 1

what is bradycardia

Answer 1

resting heart rt is below 60

Question 2

what is tachycardia

Answer 2

resting heart rate is above 100 bpm

Question 3

where does the blood and oxygen supply come from

Answer 3

in the heart it comes from the coronary arteries/veins

Question 4

where does the deoxygenated blood return to the heart

Answer 4

1. conorary veins empty into coronary sinus, which empties to the right atrium
2. few small veins empy directly into right atrium

Question 5

Using a stent to treat a
heart attack is an example
of the core concept:
a. Structure function
b. Information flow
c. Evolution
d. Transformation of energy and matter

Answer 5

Structure function

Question 6

Which of the following statements is true
regarding a heart’s ability to beat outside of the
body?
a. Innervation of the heart by the nervous system is required for
action potentials
b. Blood flow into the heart is required for action potentials
c. Release of epinephrine by the sympathetic nervous system is
required for action potentials
d. Skeletal muscle cell contraction around the heart is required
to stimulate action potentials
e. The heart needs nothing else to cause an action potential

Answer 6

e. The heart needs nothing else to cause an action potential

Question 7

what are pace maker cells

Answer 7

make up 1% of specializes cardiomyocytes withing the sinoatrial node

Question 8

what are pace maker cells

Answer 8

make up 1% of specializes cardiomyocytes withing the sinoatrial node

Question 9

what is unique about pacemaker cells

Answer 9

it has no resting membrane potenital

Question 10

in pace maker cells what causes deplorization

Answer 10

Na+ going in, it is slow depolarization

Question 11

what is the first voltage gated channel to open in pace maker cells

Answer 11

CA2+

Question 12

what is the 2nd voltage gated channel to open in pace maker cells

Answer 12

K+ going out causing repolarization

ca2+ closes

Question 13

In which stage are positive ions flowing into the
pacemaker cell through non-leak channels?
a. A
b. B
c. C
d. D
e. None of the above

lect 31 image

Answer 13

a.b. d

Question 14

hat if those pacemaker cells in the SA node stop
working properly?
a. Contractile cells in the heart can take over the
pacemaker function
b. Neurons that innervate the heart can stimulate
action potentials in the SA node
c. Your heart will immediately stop beating
d. Pacemaker cells in other parts of the heart can take
over the pacemaker function

Answer 14

d. Pacemaker cells in other parts of the heart can take
over the pacemaker function

Question 15

what are laten pacemakers

Answer 15

they are cells that can take over other areas of the heart with pacemaker activiy

can only help the heart if SAnode is supressed or fst instrinsic firing

Question 16

all conducitng systems (sa,avnose , av bundle etc) autorhythmic?
T/F

Answer 16

TRUE with sa being the primary pacemaker due to fastest firing rate of all potenial pacemaker

sa> av> bundle cells