Vascular Physiology - Blood Pressure

1. During systole, an artery wall expands with new blood, whereas during diastole, the artery wall elastically retracts to original position, propelling blood forward.

True

False

Slide 24 & 25. Note this is in the arteries (the pressure resevoir) because they contain lots of elastic fibers. This does not happen in all BV

Explanation

Slide 24 & 25. Note this is in the arteries (the pressure resevoir) because they contain lots of elastic fibers. This does not happen in all BV

2. Which of the blood vessel layers contains smooth muscle and elastic fibers?

Internal elastic lamina

Tunica externa

Tunica intima

Tunica media

Slide 5

Explanation

Slide 5

3. Elephantiasis is caused by a malfunction mainly in the _________

Venous system

Endocrine system

Nervous system

Lymphatic system

Slide 134

Explanation

Slide 134

4. When comparing the arterioles to capillaries, blood pressure is smaller in the ______ and diameter is larger in the _______

Capillaries, arterioles

Arterioles, capillaries

Capillaries, capillaries

Arterioles, arterioles

Slide 9 & 12. Pressure continuously decreases as we move further through systemic circulation. BV diameter is smallest in the capillaries.

Explanation

Slide 9 & 12. Pressure continuously decreases as we move further through systemic circulation. BV diameter is smallest in the capillaries.

5. If blood flow is abnormally high to the brain, a flow autoregulation mechanism would act to _____ the blood vessel diameter in order to _____ blood flow

Decrease, decrease

Increase, increase

Decrease, increase

Flow autoregulation mechanisms would not act in this situation

In the given scenario, if blood flow to the brain is abnormally high, a flow autoregulation mechanism would act to decrease the blood vessel diameter in order to decrease blood flow. This mechanism helps to maintain a stable blood flow to the brain by adjusting the diameter of the blood vessels. By decreasing the diameter, the flow of blood is reduced, preventing excessive blood flow to the brain.

Explanation

In the given scenario, if blood flow to the brain is abnormally high, a flow autoregulation mechanism would act to decrease the blood vessel diameter in order to decrease blood flow. This mechanism helps to maintain a stable blood flow to the brain by adjusting the diameter of the blood vessels. By decreasing the diameter, the flow of blood is reduced, preventing excessive blood flow to the brain.

6. Epinephrine can cause both vasoconstriction and vasodilation on arteriolar smooth muscle

True

False

However alpha receptors (vasoconstriction) outnumber beta receptors (dilation) so constriction is usually seen. ****skeletal muscles contain more beta receptors and so dilation is seen there*****

Explanation

However alpha receptors (vasoconstriction) outnumber beta receptors (dilation) so constriction is usually seen. ****skeletal muscles contain more beta receptors and so dilation is seen there*****

7. Blood flow is faster in venules than in capillaries

True

False

Slide 37 & 38

Explanation

Slide 37 & 38

8. Resistance is inversely proportional to the viscosity of the blood.

True

False

Resistance is directly proportional to viscosity of the blood. If there is greater viscosity there is more resistance.

Explanation

Resistance is directly proportional to viscosity of the blood. If there is greater viscosity there is more resistance.

9. A person's resting heart rate is 130/80, their pulse pressure is ___ mm Hg. Their mean arterial pressure is ____.

50, 96.67

130, 96.67

80, 50

50, 80

Pulse pressure = Systolic - Diastolic = 130 - 80 = 50......................... MAP = DP + 1/3(Pulse pressure) = 80 + (1/3)*50 = 96.67

Explanation

Pulse pressure = Systolic - Diastolic = 130 - 80 = 50......................... MAP = DP + 1/3(Pulse pressure) = 80 + (1/3)*50 = 96.67

10. The major source of resistance in systemic circulation is at the level of the ______

Arteries

Arterioles

Capillaries

Aorta

Arterioles are the small blood vessels that connect arteries to capillaries. They play a crucial role in regulating blood flow and blood pressure. Due to their small diameter, arterioles offer the greatest resistance to blood flow in the systemic circulation. This resistance is important for maintaining proper blood pressure and ensuring that blood is distributed appropriately to different organs and tissues. Therefore, the major source of resistance in systemic circulation is at the level of the arterioles.

Explanation

Arterioles are the small blood vessels that connect arteries to capillaries. They play a crucial role in regulating blood flow and blood pressure. Due to their small diameter, arterioles offer the greatest resistance to blood flow in the systemic circulation. This resistance is important for maintaining proper blood pressure and ensuring that blood is distributed appropriately to different organs and tissues. Therefore, the major source of resistance in systemic circulation is at the level of the arterioles.

11. Which of the following hormones decrease blood pressure?

ANP

ADH

Angiotensis 2

Renin

ANP, or atrial natriuretic peptide, is a hormone that is released by the heart in response to high blood pressure. It acts to decrease blood pressure by promoting the excretion of sodium and water in the kidneys, leading to increased urine production. This helps to reduce the volume of blood in the bloodstream, ultimately lowering blood pressure.

Explanation

ANP, or atrial natriuretic peptide, is a hormone that is released by the heart in response to high blood pressure. It acts to decrease blood pressure by promoting the excretion of sodium and water in the kidneys, leading to increased urine production. This helps to reduce the volume of blood in the bloodstream, ultimately lowering blood pressure.

12. If a blood vessel decreased in radius by 3 times, the resistance would ______ by a factor of _____ times

Decrease, 81

Increase, 81

Increase, 12

Decrease, 12

Resistance is inversely proportional to the 4th power of radius. Slide 46 & 48

Explanation

Resistance is inversely proportional to the 4th power of radius. Slide 46 & 48

13. At the venous end of a capillary bed, the net filtration pressure is directed _____________

Inwards towards the capillary (Negative net filtration)

Outwards escaping the capillary (Positive net filtration)

0

Inward or Outwards depending on where the capillary bed is located

The arteriole end is positive (~ 10 mm Hg) and the venule end is negative (~ -7 mm Hg)

Explanation

The arteriole end is positive (~ 10 mm Hg) and the venule end is negative (~ -7 mm Hg)

14. Blood flow to coronary vessels occurs _____

Mainly during Diastole

Mainly during Systole

Equally throughout diastole and systole

No blood flow to coronary vessels

Because the coronary vessels are compressed during systole, flow occurs mainly during diastole.

Explanation

Because the coronary vessels are compressed during systole, flow occurs mainly during diastole.

15. The largest drop in blood vessel pressure occurs at the level of _______

Arterioles

Arteries

Capillaries

Venules

Arterioles are small blood vessels that connect arteries to capillaries. They play a crucial role in regulating blood flow and blood pressure. Due to their small size and high resistance, arterioles experience the largest drop in blood vessel pressure. This is because the arterioles are responsible for controlling the amount of blood that flows into the capillaries, where exchange of nutrients and waste products occurs. Therefore, the correct answer is arterioles.

Explanation

Arterioles are small blood vessels that connect arteries to capillaries. They play a crucial role in regulating blood flow and blood pressure. Due to their small size and high resistance, arterioles experience the largest drop in blood vessel pressure. This is because the arterioles are responsible for controlling the amount of blood that flows into the capillaries, where exchange of nutrients and waste products occurs. Therefore, the correct answer is arterioles.

16. The hematocrit ratio _______ (Select 3)

Is generally lower for a female than for a male

Is generally higher for a female than for a male

Is the % volume of blood that is Red blood cells

Would most likely increase in a person after moving to a higher altitude location

Would most likely decrease in a person after moving to a higher altitude location

Hematocrit ratio is the % of blood volume that is red blood cells. It is higher generally higher in males. It would increase after moving to a high altitude location because the atmosphere would have less oxygen, triggering an increase in red blood cell production and therefore a higher hematocrit ratio.

Explanation

Hematocrit ratio is the % of blood volume that is red blood cells. It is higher generally higher in males. It would increase after moving to a high altitude location because the atmosphere would have less oxygen, triggering an increase in red blood cell production and therefore a higher hematocrit ratio.

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17. In systemic circulation, blood pressure ______ as distance from the left ventricle increases and is lowest in the _______

Increases, capillaries

Decreases, capillaries

Decreases, blood entering right atrium

Increases, arterioles

Slide 11-13. Blood pressure is highest in aorta and continuously decreases as it moves along systemic circulation.

Explanation

Slide 11-13. Blood pressure is highest in aorta and continuously decreases as it moves along systemic circulation.

18. Which of the following is true regarding the veins/venous system (Select 2)

They are more compliant than arteries

About 60% of blood volume is in the systemic veins

A small change in venous volume will result in a large change in venous pressure

SV is independent of venous pressure

Veins are more compliant than arteries because they have thinner walls and larger lumens, allowing them to stretch and accommodate changes in blood volume. This compliance helps to maintain blood pressure and prevent damage to the blood vessels. About 60% of the blood volume is in the systemic veins, which act as a reservoir for blood and can be quickly mobilized to maintain blood flow to vital organs.

Explanation

Veins are more compliant than arteries because they have thinner walls and larger lumens, allowing them to stretch and accommodate changes in blood volume. This compliance helps to maintain blood pressure and prevent damage to the blood vessels. About 60% of the blood volume is in the systemic veins, which act as a reservoir for blood and can be quickly mobilized to maintain blood flow to vital organs.

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19. During muscle contraction, the increased oxygen consumption stimulates production/release of compounds locally that dilate the blood vessel and cause an increase in blood flow to the muscle. This is an example of _________.

Flow autoregulation

Myogenic flow autoregulation

Reactive hyperemia

Active hyperemia

This is active hyperemia because blood flow is increased in response to increased metabolic activity.

Explanation

This is active hyperemia because blood flow is increased in response to increased metabolic activity.

20. In a capillary, ionized and polar molecules will diffuse through the capillary wall by

Diffusing through the capillary plasma membrane

By passing through intercellular clefts

None of these

All of the these

Slide 107 & 114

Explanation

Slide 107 & 114

21. Total peripheral resistance is ______ the resistance of any individual artery.

Less than

Greater than

Equal

Independent

Total peripheral resistance (TPR) is a parallel type of resistance. Organ resistance is in series (you have to add all the individual resistances together).

Explanation

Total peripheral resistance (TPR) is a parallel type of resistance. Organ resistance is in series (you have to add all the individual resistances together).

22. When the diaphragm contracts, (Select 2)

Pressure in the abdominal veins increases

Pressure in the abdominal veins decreases

Pressure in the intrathoracic veins increases

Venous return is enhanced

Slide 130-132

Explanation

Slide 130-132

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23. Which of the following are paracrine substances secreted by endothelial cells that dilate the BV (Select 3)

Prostacyclin

Endothelium derived relaxing factor (EDRF)

Nitric oxide

Endothelin-1

Note Nitric oxide is a type of EDRF

Explanation

Note Nitric oxide is a type of EDRF

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24. Which of the following when increased, would increase resistance? (Select all that apply)

BV length

Hematocrit ratio

BV radius

Blood viscosity

All of the above are directly proportional to resistance (an increase in them would result in an increase in resistance). BV radius is inversely proportional (if you increase BV radius, there is less resistance). Also an increased hematocrit ratio means that the blood is more viscous, therefore has more resistance.

Explanation

All of the above are directly proportional to resistance (an increase in them would result in an increase in resistance). BV radius is inversely proportional (if you increase BV radius, there is less resistance). Also an increased hematocrit ratio means that the blood is more viscous, therefore has more resistance.

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25. Which of the following are extrinsic mechanisms of controlling blood supply to organs? (Select 2)

ADH

Flow Autoregulation

Sympathetic/Parasympathetic input

Active Hyperemia

Flow autoregulation and Active hyperemia are examples of local controls (along with reactive hyperemia and response to injury)

Explanation

Flow autoregulation and Active hyperemia are examples of local controls (along with reactive hyperemia and response to injury)

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26. Which of the following organs have their arterioles controlled by sympathetic input (Select 2)

Skin

Brain

Heart

Skeletal muscles

Brain and heart are controlled mainly by local metabolic controls.

Explanation

Brain and heart are controlled mainly by local metabolic controls.

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27. Arteriolar control of the heart vessels is mainly controlled by (Select 2)

Adenosine

Sympathetic input

Flow autoregulation

Epinephrine

Locally controlled by metabolic factors (adenosine) and flow autoregulation. Sympathetic input has little effect on coronary arterioles. Slide 94

Explanation

Locally controlled by metabolic factors (adenosine) and flow autoregulation. Sympathetic input has little effect on coronary arterioles. Slide 94

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