Chapters 19, 20, 21

Question 1

The most correct sequence in the cardiac conduction system is

Answer 1

SA node > AV node > AV bundle > bundle branches > Purkinje fibers.

Question 2

A normal heartbeat of 70 - 80 beats per minute is referred to as

Answer 2

sinus rhythm

Question 3

Closure of the AV valves occurs when

Answer 3

ventricular pressure exceeds atrial pressure.

Question 4

During a normal cardiac cycle which phase has the longest duration?

Answer 4

quiescent period

Question 5

When the atria begin depolarizing, which of the following is occuring?

Answer 5

ventricular filling

Question 6

If the time of ventricular filling were increased in duration

Answer 6

the end diastolic volume (EDV) would be greater.

Question 7

Atrial depolarization causes

Answer 7

the P wave

Question 8

Atrial systole begins

Answer 8

immediately after the P wave

Question 9

Cells of the sinoatrial node ____________ during the pacemaker potential.

Answer 9

depolarize slow

Question 10

During isovolumetric contraction, the pressure in the ventricles

Answer 10

rises rapidly

Question 11

Isovolumetric contraction occurs during the _________ of the electrocardiogram.

Answer 11

R wave

Question 12

Most of the ventricle filling occurs

Answer 12

during atrial diastole

Question 13

The long absolute refractory period of cardiocytes

Answer 13

prevents tetanus

Question 14

The pacemaker potential is a result of

Answer 14

Na+ inflow.

Question 15

The plateau in the action potential of cardiac muscle results from the action of

Answer 15

slow Ca2+ channels.

Question 16

This is the correct sequence of events of the cardiac cycle.

Answer 16

ventricular filling → isovolumetric contraction → ventricular ejection → isovolumetric relaxation

Question 17

When the left ventricle contracts, the _____ valve closes and the _____ valve is pushed open.

Answer 17

mitral; aortic

Question 18

_____________ increase(s) stroke volume.

Answer 18

Increased venous return

Question 19

Cardioinhibitory centers in the _____________ receive input from __________.

Answer 19

medulla oblongata; chemoreceptors in the aortic arch

Question 20

Congestive heart failure (CHF) of the right ventricle

Answer 20

can cause systemic edema.

Question 21

The Frank-Starling law of the heart states that stroke volume is proportional to

Answer 21

end diastolic volume. (EDV)

Question 22

The volume of blood ejected by each ventricle in one minute is called

Answer 22

cardiac output.

Question 23

These have the most control of perfusion of a capillary bed.

Answer 23

precapillary sphincters

Question 24

Arteries are sometimes called the _______________ vessels of the cardiovascular system because they have strong-resilient tissue strucure.

Answer 24

resistance

Question 25

The outermost wall of an artery or vein is called the __________________ and in large arteries and veins contains the ______________.

Answer 25

tunica externa; vasa vasorum

Question 26

Vasomotion is associated with the presence of

Answer 26

smooth muscle in the tunica media.

Question 27

Increasing preload increases the cardiac output because

Answer 27

stretching the mycardial cells increases the force of contraction due to the length/tension relationship.

Question 28

Chronotropic effects

Answer 28

can increase or decrease the heart rate.

Question 29

Bradycardia

Answer 29

can be a normal condition, as during sleep or in a well-trained athelete.

Question 30

Stimulation of the heart by the sympathetic nervous system

Answer 30

increases heart rate.

Question 31

Potassium has the greatest potential for causing chronotropic effects because

Answer 31

it is important for returning the cardiocyte to its resting membrane potential.

Question 32

Cardiac output

Answer 32

changes in response to exercise or other stimulation.

Question 33

Blood vessels that connect two capillary networks are called

Answer 33

portal systems.

Question 34

The tissue layer of a vessel that differs most in thickness when comparing arteries and veins is the

Answer 34

tunica media.

Question 35

These have the most control of perfusion of a capillary bed.

Answer 35

precapillary sphincters

Question 36

The baroreceptors

Answer 36

All of the above.

Question 37

All of these factors may increase peripheral resistance except

Answer 37

blood type.

Question 38

Venous pooling in a soldier standing at attention for a prolonged time occurs mainly when this mechanism fails.

Answer 38

skeletal muscle pump

Question 39

_______________ has the most important effect on blood velocity.

Answer 39

vessel radius

Question 40

Hypertension is commonly considered to be a chronic resting blood pressure higher than

Answer 40

140/90

Question 41

Most blood is in the

Answer 41

veins.

Question 42

Reactive hyperemia is a result of ________________ to increase perfusion into a tissue.

Answer 42

local control

Question 43

The medullary ischemic reflex results in

Answer 43

increased circulation to the brain.

Question 44

The vasomotor center of the __________________ controls blood vessels throughout the body.

Answer 44

medulla oblongata

Question 45

The velocity of blood flow decreases when

Answer 45

viscosity increases.

Question 46

Vasomotion is associated with the presence of

Answer 46

smooth muscle in the tunica media.

Question 47

Blood flow is pulsatile in arteries and veins, but it is steady in capillaries.

Answer 47

False

Question 48

Blood flow through a capillary bed is regulated by precapillary sphincters.

Answer 48

True

Question 49

Generalized vasomotion can raise or lower blood pressure throughout the body.

Answer 49

True

Question 50

Reduced capillary reabsorption of fluid can lead to edema. Which of the following does not contribute to edema?

Answer 50

extreme muscular activity

Question 51

The most important mechanism of exchange between blood and tissue fluid is ________________.

Answer 51

diffusion

Question 52

The venous return of blood back to the heart is encouraged by

Answer 52

gravity acting on the large veins above the heart.

Question 53

______________ shock occurs when bacterial toxins trigger vasodilation and increase capillary permeability.

Answer 53

Septic

Question 54

________________ by the capillaries at their venous end.

Answer 54

Waste products are taken up

Question 55

Decompensated shock is normally corrected by the body's homeostatic mechanisms.

Answer 55

False

Question 56

Generalized vasomotion can raise or lower blood pressure throughout the body.

Answer 56

True

Question 57

Most tissue fluid is reabsorbed by the lymphatic system.

Answer 57

False

Question 58

Myocardial infarction can lead to _______________ shock.

Answer 58

cardiogenic

Question 59

The most important force driving filtration at the arterial end of a capillary is

Answer 59

blood hydrostatic pressure.

Question 60

The most important force driving reabsorption at the venous end of a capillary is

Answer 60

blood colloid osmotic pressure.

Question 61

The three main functions of the lymphatic system include all but which of the following?

Answer 61

waste removal

Question 62

Which of the following inhibitors of microbial growth is a component of the perspiration on our skin?

Answer 62

lactic acid.

Question 63

_____________ are the largest of the lymphatic vessels and they empty into the _______________.

Answer 63

Collecting ducts; subclavian veins

Question 64

______________ are found especially in the mucous membrane, standing guard against parasites and allergens.

Answer 64

Eosinophils

Question 65

________________ are secreted by cells infected with viruses, alerting neighboring cells and protecting them from becoming infected.

Answer 65

Interferons

Question 66

All these belong to the second line of defense except

Answer 66

the gastric juices.

Question 67

All these forces help lymph to flow except

Answer 67

the lymphatic node pump.

Question 68

Complement fixation can lead to any of the following effects except

Answer 68

endogenous pyrexia.