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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

apex

lines the chambers of the heart, covers the heart valves, and is continuous with the endothelium

endocardium

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

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