Arterial and Venous systems and Lymphatics

Question 1

Which of the following factors affects pulse pressure?

• Vascular elastance
• arterial compliance
• stroke volume
• all of the above
• the first and third only

Answer 1

vascular elastance AND stroke volume

Question 2

Which of the following is the most important means for the exchange of substances between the blood and the interstitial fluid?

• blood hydrostatic pressure
• osmosis
• capillary oncotic pressure
• diffusion
• interstitial fluid hydrostatic pressure

Answer 2

diffusion

Question 3

Vascular distensibility equation

Answer 3

Vascular distensibility = increase in volume/ (increase in pressure * original volume)

Question 4

What happens when the distensibility is decreased in veins when it comes to blood storage?

Answer 4

the amount of blood stored there decreases

Question 5

Vascular compliance (capacitance) equation:

Answer 5

Vascular compliance (capacitance) = (increase in volume)/(increase in pressure)

Question 6

What characteristic of blood vessels does capacitance describe?

Answer 6

distensibility

Question 7

What is capacitance inversely proportional to?

Answer 7

elastance

Question 8

How does a greater amount of elastic tissue in blood vessels affect compliance? why?

Answer 8

the blood vessels have a lower compliance because due to the higher amount of elastic tissue the blood vessels have a higher elastance

Question 9

Pulse pressure equation

Answer 9

Pulse pressure = stroke volume/arterial compliance

Question 10

What occurs at the sharp incisura?

Answer 10

the closing of the aortic valve

Question 11

What is the progressive reduction of the pulsations in the periphery known as?

Answer 11

damping of the pressure pulses

Question 12

Why does the mean arterial pressure lie closer to diastolic than to systolic?

Answer 12

because about 60% of the cardiac cycle is spent in diastole and 40% in systole

Question 13

Mean arterial pressure equation

Answer 13

Mean arterial pressure = diastolic pressure + 1/3 pulse pressure

Question 14

What is central venous pressure?

Answer 14

pressure in the right atrium

Question 15

What is the most important factor regulating vasomotion?

Answer 15

concentration of oxygen in the tissues

Question 16

Net filtration Pressure equation

Answer 16

Net filtration pressure (NFP) = Capillary pressure (outward)(Pc) - interstitial fluid pressure (inward) (Pif) - plasma colloid osmotic (oncotic) pressure (inward) ( np) + interstitial colloid osmotic (oncotic) pressure (outward)(nif)

NFP = Pc - Pif - np + nif

Question 17

The least amount of damping of the pressure pulses would occur in which of the following components of the circulatory system?

• arterioles
• venules
• femoral artery
• capillaries

Answer 17

femoral artery

Question 18

What are the comparison of distensibility between arteries and veins?

Answer 18

• veins are about 8 times more distensible than arteries
• Pulmonary vein distensibilities are about the same as for systemic veins
• pulmonary artery distensibilities are about 6 times that of systemic arteries

Question 19

What is capacitance directly proportional to and inversely proportional to?

Answer 19

it is directly proportional to volume and inversely proportional to pressure

Question 20

Where is capacitance higher? veins or arteries

Answer 20

veins

Question 21

How does age affect capacitance and what does this cause?

Answer 21

it decrease with age and can be a cause of hypertension

Question 22

What are the factors that increase venous return and increase right atrial pressure?

Answer 22

• increased blood volume
• increased peripheral venous pressures due to increased large vessel tone
• dilation of arterioles

Question 23

What is the precapillary sphincter’s function?

Answer 23

it is smooth muscle fiber that encircles capillary at point where it orginates from a metarteriole and controls how much blood will enter the system

Question 24

What are starling forces and what do they determine?

Answer 24

they are the forces inside and outside the capillary that determine direction of diffusion into or out of a capillary

Question 25

What are the 4 starling forces for a capillary and which direction are the going?

Answer 25

1. Capillary pressure (outward)
2. interstitial fluid pressure (inward)
3. Capillary plasma colloid osmotic pressure (inward)
4. interstitial fluid colloid osmotic pressure (outward)

Question 26

What are the sum of the starling forces equal too?

Answer 26

net filtration pressure

Question 27

Net filtration pressure equation

Answer 27

NFP = Capillary pressure - intersitial fluid pressure - plasma colloid osmotic pressure + interstitial colloid osmotic pressure

Question 28

What is the capillary filtration coefficient?

Answer 28

takes into consideration the number and size of pores to account for the differences in leakiness for different capillaries

Question 29

What are the 3 forces moving fluid outward?

Answer 29

capillary pressure
NEGATIVE intersitial free fluid pressure
intersitial fluid colloid osmotic pressure

Question 30

What is the force moving fluid in to the capillary?

Answer 30

plasma colloid osmotic pressure

Question 31

What is the net outward force for a arterial end capillary?

Answer 31

13 mm hg

Question 32

What is the net inward force at venous end of capillary?

Answer 32

7 mm Hg which is the net reabsorption force

Question 33

What are the 4 factors that increase lymph flow and also interstitial fluid pressure?

Answer 33

• Elevated capillary hydrostatic pressure
• decreased plasma colloid osmotic pressure
• increased interstitial fluid colloid osmotic pressure
• increased permeability of capillaries

Question 34

Rate of lymph flow equation

Answer 34

Rate of lymph flow= interstitial fluid pressure X activity of lymphatic pump