PHYSIOLOGY OF THE HEART CHAPTER 22 Flashcards
The __________ extends through the interventricular septum toward the apex of the heart.
AV node
SA node
right and left bundle branches
AV bundle
right and left bundle branches
2 The __________ component of the ECG represents the depolarization of the ventricles.
QRS complex
S-T segment
P-R segment
R-R interval
QRS complex
The __________ causes the first heart sound heard through a stethoscope.
closing of the semilunar valves
opening of the atrioventricular valves
closing of the atrioventricular valves
opening of the semilunar valves
closing of the atrioventricular valves
The __________ causes the second heart sound heard through a stethoscope.
closing of the atrioventricular valves
opening of the semilunar valves
opening of the atrioventricular valves
closing of the semilunar valves
closing of the semilunar valves
During the BIOPAC activity, the subject’s heart rate increases after exercise because
the body needs to be stronger.
the body needs to increase its number of red blood cells.
the body has a lower demand for nutrients.
the body has a greater demand for oxygen.
the body has a greater demand for oxygen.
During the BIOPAC activity, the subject’s Q-T interval shortens after physical exercise
because the heart is beating faster; the length of time for a ventricular contraction must shorten.
because the heart muscle is receiving too much oxygen.
because the heart contractions are stronger.
because the heart is beating too fast and is compensating.
because the heart is beating faster; the length of time for a ventricular contraction must shorten.
Which term is used to describe the structure that is also called the “pacemaker” of the heart?
bundle branch
AV node
SA node
terminal branch
SA node
The __________ is the first of the deflection waves on a typical ECG.
P-Q wave
QRS complex
P wave
T wave
Correct Answer:
P wave
What structure or activity is the direct source of the sounds in the heartbeat?
the contraction of ventricles
the rush of blood through the chambers
the snapping shut of valves
the electrical impulse between the SA and AV nodes
the snapping shut of valves
How many electrodes should be attached to the left forearm to record a 3 lead ECG?
0 1 2 3
Correct Answer:
0
The __________ is the term used to describe the chart produced when recording the electrical activity of the heart.
electrocardiogram
electrointrinsogram
electromyogram
electroencephalogram
electrocardiogram
An electrocardiogram contains three \_\_\_\_\_- \_\_\_\_\_\_\_\_ and is recorded with an -\_\_\_\_\_\_\_\_\_. An electrocardiogram (ECG) consists of three deflection waves (- wave, --- wave, and - wave) and a straight baseline called the ------- line. An ECG is recorded using an instrument called an electrocardiograph.
An electrocardiogram contains three deflection waves and is recorded with an electrocardiograph. An electrocardiogram (ECG) consists of three deflection waves (P wave, QRS wave, and P wave) and a straight baseline called the isoelectric line. An ECG is recorded using an instrument called an electrocardiograph.
Action potentials generated by the autorhythmic cells spread to the contractile cells through what in the membrane?
Desmosomes
Gap junctions
Tight junctions
Protein carriers
Gap junctions
There are three channels essential for generating an action potential in autorhythmic cells. Which of the following ion channels have ions that move out of the cell?
Fast calcium
Potassium
Sodium
Potassium
If the sodium or fast calcium channels are open, the inside of the cell would become relatively more:
positive.
negative.
positive
The pacemaker potential (unstable resting membrane potential) in the SA node (an autorhythmic cell) is caused by decreased efflux of what ion?
Calcium
Sodium
Potassium
Potassium
When threshold is reached at the SA node (an autorhythmic cell), what channels open, causing further depolarization of the membrane?
Slow calcium
Fast calcium
Sodium
Potassium
Fast calcium
When threshold is reached at the SA node (an autorhythmic cell), what channels open, causing further depolarization of the membrane?
Slow calcium
Fast calcium
Sodium
Potassium
Potassium
Where is the calcium stored in contractile cells?
T tubule
Gap junctions
Myofilaments
Sarcoplasmic reticulum
Sarcoplasmic reticulum
What causes action potentials in contractile cells?
An unstable resting membrane potential
The flow of negative ions from adjacent cells
The flow of positive ions from adjacent cells
The flow of positive ions from adjacent cells
The depolarization phase of contractile cells is caused by the opening of what voltage-gated channels?
Potassium
Slow calcium
Fast sodium
Fast calcium
Fast sodium
The repolarization phase of contractile cells is delayed by the plateau phase. The opening of what voltage-gated channels is responsible for the plateau phase?
Fast calcium
Potassium
Slow calcium
Fast sodium
Slow calcium
Depolarizing current from the autorhythmic cells causes the ventricular muscle cells to
contract
Name the three channels essential for generating an action potential and indicate which way the ions move (circle the correct one):
- ______________ channels into or out of
- ______________ channels into or out of
- ______________ channels into or out of
- sodium, into
- potassium, out of
- fast calcium, into
If the sodium channel or the fast calcium channels are open, the inside of the cell would be relatively more
positive
The pacemaker potential is due to a/an ______ efflux of ____ ions compared to a normal influx of ____ ion
decreased, potassium, sodium
Threshold for the action potential in the SA node is at ____ mV. What channels open, causing depolarization? ______________
-40, fast calcium channels
The reversal of membrane potential causes the _____ channels to open, causing the ______________ of the membrane.
potassium, repolarization
The ______________ pumps sodium out and potassium into the cell, restoring ion concentrations to their resting levels.
Na+-K+ ATPase
Where is calcium stored in the contractile cells?
Sarcoplasmic reticulum
Gap junctions allow what cations to pass into the cardiac contractile cells, causing the opening of voltage-gated sodium channels?
Sodium, calcium, and potassium
State the voltage-gated channels responsible for the following stages of the action potential in cardiac contractile cells:
a. Depolarization ______________________
b. Plateau ______________________
c. Repolarization ______________________
a. fast sodium channels
b. slow calcium channels
c. potassium channels
What channels in the autorhythmic cells allow ions to leak in, producing a pacemaker potential? (Quiz section) ______________
Sodium channels
What channels in the autorhythmic cells bring about depolarization? _____________
Calcium channels
