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36 terms


Brainstem control of heart rate. The cardioacceleratory center activates sympathetic neurons and the cardioinhibitory center controls parasympathetic neurons
The first blood vessels to branch from the aorta are the
coronary arteries
The inferior point of the heart is called the
lines the chambers of the heart, covers the heart valves, and is continuous with the endothelium
In cardiac muscle
about 20 percent of the calcium ion required for contraction comes from outside the cell
If the connection between the SA node and AV node becomes blocked,
the ventricles will beat more slowly.
If there is a complete block between the SA node and the AV node, how would the ECG be affected
The rate of P waves will be faster than the rate of QRS complexes.
During the T wave of the electrocardiogram, the ventricles are
both repolarizing and relaxing
Put in correct order the sequence in which excitation would move through the conducting system of the heart:
SA node,AV node, AV bundle, bundle branches, Purkinje fibers
What causes the aortic semilunar valve to close
greater pressure in the aorta than in the left ventricle
The one-way nature of the left AV valve prevents blood flow from
the left ventricle to the left atrium
The closing of the left AV valve occurs near the beginning of
ventricular systole
The majority of ventricular filling occurs while the ventricles and atria are in what state(s)?
ventricular and atrial diastole
Left ventricular filling occurs
while the AV valve is open
during isovolumetric
Heart valves are in what state during isovolumetric contraction
The AV valves and semilunar valves are closed
The decrease in left ventricular pressure at the end of ventricular systole causes __________.
the semilunar valve to close
Ventricular diastole begins with the closing of the semilunar valves. What phase of the cardiac cycle happens between this event and the later opening of the AV valves?
isovolumetric relaxation
The first heart sound ("lub")
is associated with closing of the mitral valve.
The systolic part (both atrial and ventricular) of a cardiac cycle lasts on average
370 msec.
With each ventricular systole
blood pressure increases.
As the heart rate slows
diastole gets longer
In mitral valve prolapse, the cusps of the mitral valve are pushed into the
left atrium
end-diastolic volume
is the volume of blood in a ventricle at the beginning of systole.
Which of the following would increase cardiac output to the greatest extent?
increased heart rate and increased stroke volume
How would an increase in the sympathetic nervous system increase stroke volume?
increased contractility
By what mechanism would an increase in venous return increase stroke volume?
increased end diastolic volume
How would a decrease in blood volume affect both stroke volume and cardiac outpu
decreased stroke volume and no change in cardiac output
The volume of blood ejected from each ventricle during a contraction is called the
stroke volume.
"An increase in end-diastolic volume increases the stroke volume" is a way of stating
Starling's law of the heart.
The heart is innervated by
both parasympathetic and sympathetic nerves
Cardiac output can be increased by all of the following
increasing heart rate,
increasing ejection fraction,
decreasing end systolic volume
increasing stroke volume
What cause stroke volume to increase
when diastolic blood pressure is decreased
Activation of which kind of receptor causes heart rate to increase
beta-one receptor
End-systolic volume is defined as the
amount of blood remaining in a ventricle after contraction
Calculate cardiac output if the heart rate is 125 beats/minute, the end-diastolic volume is 130 ml, and the end-systolic volume is 40 ml.
11,250 ml / min
Heart failure
is when the heart can't maintain adequate cardiac output.
The amount of blood returning to the heart is the
The amount of blood returning to the heart is the