Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
40 Cards in this Set
- Front
- Back
|
the cardiac muscle is capable of? |
autorhythmicity |
|
|
phase 2 of the cardiac action potential, when the calcium channels remain open and potassium channels are closed, is called the? |
plateau phase |
|
|
which of the following is true of the cardiac action potential? |
the cardiac action potential is longer than the skeletal muscle action potential |
|
|
the main anatomical difference between between the frog heart and the human heart is that the frog heart has |
a single, fused ventricle |
|
|
the amplitude of the ventricular systole did not change with the more frequent stimulation because? |
new contraction could not begin until the relaxation period |
|
|
which of the following do you think contribute to the inability of cardiac muscle to be tetanized? |
a long refractory period of the cardiac action potential |
|
|
given the function of the heart, why is it important that cardiac muscle cannot reach tetanus? |
the ventricles must contract and relax fully with each beat to pump blood |
|
|
an extrasystole corresponds to? |
an extra ventricular contraction |
|
|
the effect of the parasympathetic NS on the heart is to? |
decrease heart rate |
|
|
the branch of the autonomic NS that dominates during exercise is? |
sympathetic branch |
|
|
parasympathetic stimulation reaches the heart through |
vague nerves, which are cranial nerves |
|
|
the usual pacemaker of the heart |
is the SA node |
|
|
extreme vagus nerve stimulation affects the heart by |
stopping the heart completely |
|
|
vagal escape probably involves |
sympathetic reflexes |
|
|
research shows that in the absence of neural and hormonal influences the sa node generates action potentials at a frequency of 100 times per minute. however the resting heart rate is 70 beats per minute which suggests that |
the parasympathetic NS has more control over the heart rate |
|
|
the sa node in the human heart is located |
in the right atrium |
|
|
organisms that usually maintain the same internal body temp in spite of environmental temp changes are |
homeothermic |
|
|
the general name for the process that maintains the internal body temperature in humans is |
homeostasis |
|
|
the electrolytes in a ringers solution are required to |
provide for autorhythmicity |
|
|
an internal body temp that is above normal range is |
hyperthermic |
|
|
the 5 degrees solution, the frog heart |
would be slower than baseline |
|
|
in the 32 degrees solution the frogs heart would |
beat faster than baseline |
|
|
if the human heart we’re experiencing hypothermia, what affect would it have on heart rate? |
decrease heart rate |
|
|
without the ringers solution |
spontaneous cardiac action potentials would not occur |
|
|
the parasympathetic NS releases ___________ to affect heart rate |
acetylcholine |
|
|
a cholinergic drug that worked the same as acetylcholine would |
be an agonist and decrease heart rate |
|
|
norepinephrine affects the heart rate by |
increasing the rate of depolarization and increasing frequency of action potentials |
|
|
the _________ receptor binds to norepinephrine and epinephrine |
beta 1 adrenergic |
|
|
pilocarpine decreased the heart rate. typical cholinergic agonists, it |
decrease the frequency of action potentials |
|
|
the effect of atropine was to |
mimic the sympathetic NS |
|
|
the modifiers tested that decrease the heart rate were |
digitalis and pilocarpine |
|
|
to increase the heart rate the best choices would be |
epinephrine and atropine |
|
|
which organelle in cardiac muscle stores calcium |
sarcoplasmic reticulum |
|
|
verapamil is a calcium channel blocker. it’s effects would be described as |
negative chronotropic and negative inotropic |
|
|
when the cardiac muscle cell is at rest, where is most of the potassium found? |
in cytosol |
|
|
resting cardiac muscle are most permeable to |
potassium |
|
|
the addition of most ions resulted in |
erratic heart rate |
|
|
the effect of potassium on the heart is |
negative chronotropic and inotropic |
|
|
the ion that had the most pronounced effect on the heart rate was |
potassium |
|
|
ectopic pacemakers can be caused by excessive leakage of potassium into cardiac cells, resulting in pacemakers appearing in abnormal locations in the heart muscle. this hyperkalemia decreases the resting potential of the cardiac muscle cell. what effect do you think this would have on the force of contraction |
decrease, negative inotropic |
