Which of the following are mechanisms by which epinephrine a

Which of the following are mechanisms by which
epinephrine and norepinephrine enhance the amount of
calcium in cardiac muscle cells during a fight-or-flight
response?
a) insertion of additional calcium channels
b) enhancement of calcium-ATPase activity
c) phosphorylation of sodium channels
d) increase in size of sarcoplasmic reticulum

Solution

b) enhancement of calcium-ATPase activity

The epinephrine and norepinephrine act by enhancing the calcium in cardiac muscle cells, which increase the force of contraction and rate of contraction. This results in increased sympathetic activity during the fight-or-flight response.