Deck 8: Muscle Physiology

Question 1

Organs that recondition the blood normally receive considerably more of the cardiac output than is necessary to meet their metabolic needs.

Answer 1

True

Question 2

Cardiac contraction induces blood flow in the arterial system, but it has no influence on blood flow in the veins.

Answer 2

False

Question 3

More blood is delivered to the tissues during ventricular systole than during ventricular diastole.

Answer 3

False

Question 4

Resistance to blood flow increases as the viscosity of the blood increases.

Question 5

Primary hypertension refers to chronically elevated blood pressure of unknown origin.

Question 6

The sphygmomanometer and stethoscope can be used for a direct measurement of arterial blood pressure.

Question 7

The greatest pressure drop in the vascular system occurs within the capillaries due to fluid leaving the capillaries by the process of ultrafiltration.

Question 8

Increased sympathetic stimulation causes generalized vasoconstriction.

Question 9

Using F = P/R, as resistance increases, the flow increases if the pressure is constant.

Question 10

Normally, most of the blood at any one time is in the capillary beds, because this is where material exchange is taking place.

Question 11

Irreversible shock occurs when the cardiovascular system itself starts to deteriorate as a consequence of side effects from compensatory measures to severe hypotension.

Question 12

The mean arterial pressure is a simple average of the systolic and diastolic pressures.

Question 13

Because the capillaries have the smallest radii of any vascular segment, they are the major resistive vessels.

Question 14

When the heart is not ejecting blood into the arterial system, the pressure in the arteries falls to zero as blood drains off into the rest of the vasculature.

Question 15

There is normally a net loss of fluid from a capillary at its arteriolar end.

Question 16

The pulse pressure is the maximum pressure exerted in the arteries.

Question 17

Glucose is actively transported across the capillary walls.

Question 18

Blood flows continuously through all capillaries.

Question 19

The capillary vessel walls are more permeable than the lymphatic vessel walls.

Question 20

Differences in blood flow to an organ are related to the resistance to flow offered by the arterioles that supply that organ.

Question 21

The flow rate of blood is the same in all segments of the vascular tree, but the velocity of blood flow is slower in the capillaries than in other segments of the vascular tree.

Question 22

Endothelin causes arteriolar smooth muscle contraction.

Question 23

Vasoconstriction refers to a decrease in the radius of a vessel.

Question 24

Blood flow is driven by osmotic pressure.

Question 25

There is a constant flow of blood through the capillaries even though the heart is forcing blood out into the arterial system only part of the time.

Question 26

A local increase in potassium increases the vasodilation of arterioles.

Question 27

For a blood pressure reading of 136/78 mmHg, 78 refers to the diastolic pressure.

Question 28

Velocity of blood flow is slowest in the veins because the blood must move uphill against gravity in these vessels.

Question 29

A decrease in plasma-colloid osmotic pressure will decrease ultrafiltration and increase reabsorption at the capillary level.

Question 30

The vessels with the greatest total cross-sectional area are the arteries.

Question 31

Histamine released in injured areas produces local arteriolar vasodilation.

Question 32

Arterial walls contain a thick layer of smooth muscle and an abundance of collagen and elastin fibres.

Question 33

During exercise, a larger percentage of the cardiac output travels to the skin and skeletal muscles.

Question 34

Vasopressin is a vasodilator.

Question 35

A metarteriole is located between an arteriole and a venule.

Question 36

Sympathetic activity controls the degree of resistance in arterioles.

Question 37

There is normally a net gain of fluid in the capillary at the venular end.

Question 38

The effective circulating volume is reduced when blood collects in distended varicose veins.

Question 39

The interstitial fluid is not part of the ECF.

Question 40

Bulk flow refers to the volume of blood ejected by each ventricle each minute.

Question 41

The baroreceptors are usually no longer functional in the presence of hypertension.

Question 42

Arteries that have lowered compliance are not as elastic.

Question 43

Cardiovascular changes associated with exercise can be accounted for by local metabolic influences on skeletal muscle arterioles coupled with adjustments via the baroreceptor reflex.

Question 44

Hyperaemia occurs in response to circulating epinephrine.

Question 45

Measurement of arterial pressure using a sphygmomanometer is possible because turbulent blood flow that occurs as arterial pressure overcomes a partially occluded artery, and can be heard by a stethoscope placed just over the artery.

Question 46

Organs that do not adjust the blood are more vulnerable to reductions in blood flow than are organs that perform homeostatic functions on the blood.

Question 47

During exercise, blood flow to the digestive tract is increased by dilation of the arterioles of the digestive tract.

Question 48

Increased tissue respiration rates cause local vasodilation of arterioles.

Question 49

The regulation of blood flow in the arterioles of the brain is under the control of mainly the sympathetic nervous system.

Question 50

At any point in time, most of the blood flow in the body is contained in the capillaries.

Question 51

Plasma proteins are responsible for the plasma-colloid osmotic pressure.

Question 52

The ultimate function of the circulatory system is accomplished by the heart.

Question 53

If driving pressure is constant, flow will double when the radius increases by twofold.

Question 54

If the diastolic pressure and systolic pressure were both increased by 18 mmHg, then the pulse pressure would be increased by 19 mmHg.

Question 55

A major function of the arteries is to serve as a blood reservoir.

Question 56

Oedema refers to excess interstitial fluid.

Question 57

Local control mechanisms can override sympathetic control of changes in the size of arterioles.

Question 58

Arteriolar resistance is regulated by both local controls and extrinsic controls.

Question 59

As the concentration of red blood cells increases in the blood, the viscosity of the blood increases.

Question 60

The skeletal muscle pump adds to the effect of gravity on the venous system.

Question 61

The main process by which exchange of solutes occurs between the blood and interstitial fluid at the capillary level is passive diffusion down concentration gradients.

Question 62

Which of the following statements correctly describes veins?

A)Their walls are highly muscular.
B)Their walls consist of thick layers of elastic tissues.
C) They serve as a blood reservoir.
D) They transport blood away from the heart.

Question 63

What is the location of the receptors that detect changes in blood pressure?

A)carotid sinus
B)spinal cord
C) hypothalamus
D) medulla

Question 64

Which of the following factors does NOT promote the function of the capillaries?

A)blood pressure forcing fluid out of these vessels
B)a small total surface area
C) an osmotic pressure drawing fluid into these vessels
D) pores in the endothelial wall

Question 65

Which of these conditions is NOT a complication of uncontrolled hypertension?

A)cerebrovascular accident (stroke)
B)endocarditis
C) renal impairment
D) congestive heart failure

Question 66

Due to contraction of its smooth muscle layer, an artery ensures that blood flows constantly.

Question 67

During strenuous exercise, where does blood flow increase?

A)in the heart because of local control factors
B)in the brain because of reflex control factors
C) in the skeletal muscles because of local control factors
D) in the lungs because of local control factors

Question 68

Which of the following does NOT occur to compensate for a fall in blood pressure below normal?

A)increase in cardiac output
B)decrease in total peripheral resistance
C) increase in heart rate
D) venous vasoconstriction

Question 69

Because the arteries have large radii, they serve as excellent rapid-transit passageways for blood. What is their second function-which is related to their elasticity-in maintaining blood flow during diastole?

A)cardiac reserve
B)venous reserve
C) arterial capacitance
D) pressure reservoir

Question 70

All the fluid forced out of the capillaries is filtered through the lymphatics before being returned to the venous blood.

Question 71

What are the major resistance vessels of the body?

A)arteries
B)arterioles
C) capillaries
D) veins

Question 72

The extra fluid filtered but not reabsorbed at the capillary level is picked up by the lymphatics.

Question 73

Oedema, venous pooling, and a reduction in cardiac output are consequences of standing still for a long time.

Question 74

The primary means by which individual substances are exchanged between the blood and the surrounding tissues is by bulk flow.

Question 75

The capillaries have an overall, tremendous cross-sectional area.

Question 76

Which of these changes will increase fluid reabsorption by the capillaries?

A)decreased interstitial fluid hydrostatic pressure
B)increased capillary blood pressure
C) increased plasma-colloid osmotic pressure
D) increased interstitial fluid-colloid osmotic pressure

Question 77

What is the major site of sympathetic blood flow control (resistance changes)?

A)arteriole
B)capillary
C) metarteriole
D) artery

Question 78

The colloidal osmotic pressure in the blood plasma draws fluid into the capillary.

Question 79

As metabolic activity of an organ or tissue increases, blood flow to that organ increases. What is the term for this phenomenon?

A)pressure autoregulation
B)tissue anoxia
C) active hyperaemia
D) hypertension

Question 80

Which statement correctly describes vascular resistance?

A)It is a measure of the hindrance to blood flow through a vessel caused by friction between the moving fluid and stationary vascular walls.
B)It is doubled when the radius of the vessel is wider than normal.
C) It is inversely proportional to blood viscosity.
D) It is increased when blood vessel length is shorter.