Circulatory system 2

Question 1

The period of time in which the myocardium is insensitive to further stimulation is called the
Select one:
a. absolute refractory period.
b. hyperpolarization period.
c. AV period.
d. SA period.
e. ectopic focus.

Answer 1

a. absolute refractory period.

Question 2

The volume of blood pumped during each cardiac cycle is the
Select one:
a. stroke volume. 
b. cardiac output.
c. cardiac reserve.
d. end-systolic volume.
e. end-diastolic volume.

Answer 2

a. stroke volume

Question 3

These vessels empty blood into the left atrium.
Select one:
a. aorta
b. right atrium
c. pulmonary trunk
d. pulmonary arteries
e. pulmonary veins

Answer 3

e. pulmonary veins

Question 4

The valve located between the right ventricle and the pulmonary trunk is the
Select one:
a. aortic semilunar valve.
b. pulmonary semilunar valve.
c. tricuspid valve.
d. mitral valve.
e. bicuspid valve.

Answer 4

b. pulmonary semilunar valve.

Question 5

Which of the following is true?

Select one:

a. Blood enters the right and left atria only during diastole.
b. Most ventricular filling occurs before the atria contract.
c. During ventricular systole, the AV valves open.
d. The semilunar valves remain closed throughout ventricular systole.
e. Most of end-diastolic volume comes from active filling.

Answer 5

e. Most of end-diastolic volume comes from active filling.

Question 6

The P wave of an ECG indicates
Select one:
a. atrial depolarization.
b. atrial repolarization.
c. ventricular depolarization.
d. ventricular repolarization.
e. threshold.

Answer 6

a. atrial depolarization

Question 7

Which of the following phrases would apply to cardiac muscle cells?

Select one:

a. are organized in parallel columns or bundles
b. contain actin but no myosin
c. develop a significant oxygen debt during systole
d. are multinucleated like skeletal muscle cells.
e. possess special cell-to-cell contacts called intercalated discs

Answer 7

e. possess special cell-to-cell contacts called intercalated discs

Question 8

The cardioregulatory center of the brain is located in the
Select one:
a. hypothalamus.
b. medulla oblongata.
c. cerebellum.
d. cerebrum.
e. diencephalons.

Answer 8

b. medulla oblongata.

Question 9

An incompetent pulmonary semilunar valve could result in less blood reaching the
Select one:
a. lungs.
b. heart muscle.
c. right ventricle.
d. aorta.
e. right atrium.

Answer 9

a. lungs.

Question 10

Which of the following will depolarize immediately after the AV node depolarizes?

Select one:

a. the AV bundle
b. Purkinje fibers
c. atrial myocardium
d. bundle branches in the ventricular septum
e. the SA node

Answer 10

a. the AV bundle

Question 11

Coronary artery disease can diminish myocardial blood flow resulting in the death of myocardial cells. This condition is known as a myocardial
Select one:
a. attack.
b. angina.
c. necrosis.
d. cirrhosis.
e. infarction.

Answer 11

e. infarction.

Question 12

The AV valve that is located on the same side of the heart as the origin of the aorta is the

Select one:

a. bicuspid or mitral valve.
b. tricuspid valve.
c. aortic semilunar valve.
d. pulmonary semilunar valve.
e. coronary sinus valve.

Answer 12

a. bicuspid or mitral valve.

Question 13

If the SA node is nonfunctional, which of the following is most likely to occur?
Select one:
a. The heart will go into asystole (stop).
b. Tachycardia will develop.
c. Another portion of the heart will become the pacemaker.
d. The heart will go into defibrillation.
e. The heart will be desensitized.

Answer 13

c. Another portion of the heart will become the pacemaker.

Question 14

These vessels transport blood to the right and left lungs.
Select one:
a. aorta
b. right atrium
c. pulmonary trunk
d. pulmonary arteries
e. pulmonary veins

Answer 14

d. pulmonary arteries

Question 15

Angina pectoris is chest pain caused by reduced
Select one:
a. stimulation of the myocardium.
b. blood supply to cardiac muscle.
c. fluid in the pericardial sac.
d. contractility of the heart.
e. action potentials from SA node.

Answer 15

b. blood supply to cardiac muscle.

Question 16

This blood vessel carries blood from the left ventricle.
Select one:
a. aorta
b. right atrium
c. pulmonary trunk
d. pulmonary arteries
e. pulmonary veins

Answer 16

a. aorta

Question 17

Blood vessels enter and exit from the \_\_\_\_\_ of the heart.
Select one:
a. apex
b. base
c. auricles
d. trigone
e. inferior aspect

Answer 17

b. base

Question 18

Contraction of the papillary muscles would

Select one:

a. eject blood from the ventricles.
b. prevent the AV valves from protruding into the atria.
c. close the semilunar valves.
d. cause the atria to eject their contents into the ventricles.

Answer 18

b. prevent the AV valves from protruding into the atria

Question 19

Blood returning to the heart from the systemic circuit first enters the
Select one:
a. right atrium.
b. right ventricle.
c. left atrium.
d. left ventricle.
e. conus arteriosus.

Answer 19

a. right atrium

Question 20

Which of the following layers forms the bulk of the heart wall?

Select one:

a. epicardium
b. pericardium
c. endocardium
d. myocardium
e. visceral pericardium

Answer 20

d. myocardium

Question 21

The chamber of the heart that endures the highest pressure is the
Select one:
a. right atrium.
b. left atrium.
c. right ventricle.
d. left ventricle.
e. coronary sinus.

Answer 21

d. left ventricle.

Question 22

If the heart receives more sympathetic stimulation than parasympathetic stimulation, the heart will
Select one:
a. increase its rate and force of contraction.
b. contract with greater force but at a slower rate.
c. decrease both its rate and force of contraction.
d. contract with less force but at a faster rate.
e. decrease rate, but increase force of contraction.

Answer 22

a. increase its rate and force of contraction.

Question 23

If cardiac muscle cells are unable to repolarize, this would cause
Select one:
a. cardiac output to increase.
b. no harm. These cells can spontaneously depolarize anyway.
c. the heart rate to decrease. It might cause cardiac arrest.
d. an increased demand on mitochondria to produce more ATP.
e. tachycardia.

Answer 23

c. the heart rate to decrease. It might cause cardiac arrest

Question 24

The "pacemaker" of the heart is the
Select one:
a. right bundle branch.
b. left bundle branch.
c. AV node.
d. SA node.
e. PM node.

Answer 24

d. SA node.

Question 25

In the cardiac cycle Select one: a. the right atrium and the right ventricle contract simultaneously. b. the two atria relax while the two ventricles contract. c. the left atrium contracts before the right atrium. d. all four chambers of the heart contract at the same time. e. all four chambers of the heart are in systole at the same time.

Answer 25

d. all four chambers of the heart contract at the same time.

Question 26

Which of the following will increase the heart rate? Select one: a. a rise in pH b. an increase in the level of carbon dioxide in the blood c. an increase in the level of blood oxygen d. an increase in blood pressure e. a decrease in the level of carbon dioxide in the blood

Answer 26

b. an increase in the level of carbon dioxide in the blood

Question 27

Cardiac muscle cells Select one: a. have smooth ER but no T tubules. b. form the heart valves. c. are maintained by an extensive capillary network. d. develop a significant oxygen debt during systole. e. do not contain actin and myosin like skeletal muscle cells.

Answer 27

c. are maintained by an extensive capillary network.

Question 28

In a normal electrocardiogram, the Select one: a. P wave results from repolarization of the atria. b. QRS complex results from ventricular depolarization. c. P wave occurs after the QRS complex but before the T wave. d. T wave represents depolarization of the atria. e. repolarization of the atria is clearly visible.

Answer 28

b. QRS complex results from ventricular depolarization.

Question 29

``` Blood in the pulmonary veins returns to the Select one: a. right atrium. Incorrect b. left atrium. c. right ventricle. d. left ventricle. e. coronary sinus ```

Answer 29

c. right ventricle.

Question 30

``` Chemoreceptors sensitive to blood carbon dioxide levels are primarily located in the Select one: a. renal arteries. b. carotid arteries. c. right atrium. d. left ventricle. e. jugular veins. ```

Answer 30

b. carotid arteries.

Question 31

``` The product of the stroke volume times the heart rate is known as the Select one: a. end-diastolic volume. b. end-systolic volume. c. cardiac output. d. cardiac reserve. e. venous return. ```

Answer 31

c. cardiac output.

Question 32

Which of the following sequences is correct? Select one: a. AV node, AV bundle, SA node, Purkinje fibers, bundle branches b. Purkinje fibers, bundle branches, AV node, AV bundle, SA node c. SA node, AV node, AV bundle, bundle branches, Purkinje fibers d. SA node, AV bundle, AV node, bundle branches, Purkinje fibers Incorrect e. AV node, SA node, bundle branches, AV bundle, Purkinje fibers

Answer 32

not d - i don't know the answer

Question 33

Contraction of the ventricles is referred to as ventricular Select one: a. systole. b. diastole. c. fibrillation. d. ischemia. e. depolarization.

Answer 33

a. systole.

Question 34

Stimulation of the heart via the sympathetic nerves would Select one: a. decrease heart rate. b. decrease stroke volume. c. increase the force of ventricular contraction. d. increase end-systolic volume. e. not affect heart rate and force of contraction.

Answer 34

c. increase the force of ventricular contraction.

Question 35

The tricuspid valve is closed Select one: a. during active filling of the ventricles. b. when the mitral valve is open. c. while the atria are contracting. d. during ejection. e. during passive filling of the ventricles. Incorrect

Answer 35

not e - i don't know this answer

Question 36

``` Blood in the superior vena cava will enter the _____. Select one: a. aorta b. right atrium c. pulmonary trunk d. pulmonary arteries e. pulmonary veins ```

Answer 36

b. right atrium

Question 37

``` Ventricular contraction begins at the Select one: a. AV bundle. b. apex of the heart. c. base of the heart. d. superior portion of the interventricular septum. e. top of the ventricles. ```

Answer 37

b. apex of the heart.

Question 38

The long refractory period observed in cardiac muscle Select one: a. prolongs depolarization of the cardiac muscle. b. prevents tetanic contractions of the cardiac muscle. c. ensures that the heart has adequate time to contract. d. prevents the heart rate from slowing down. e. prevents an increase in heart rate.

Answer 38

not c - i don't know this answer

Question 39

``` An incompetent mitral valve may cause blood to back up into the Select one: a. aorta. b. left atrium. c. left ventricle. d. coronary circulation. e. right atrium. ```

Answer 39

b. left atrium.

Question 40

Which of the following factors would cause an increase in heart rate? Select one: a. increased parasympathetic stimulation b. stimulation of baroreceptors in the aorta c. increased epinephrine (adrenalin) release from the adrenal medulla d. increased production of atrial natriuretic factor e. vagal stimulation

Answer 40

c. increased epinephrine (adrenalin) release from the adrenal medulla