Microcirculation

Question 1

Which type of capillary has the least porous endothelial cells and lacks fenestrations?
a) Fenestrated capillary
b) Sinusoidal capillary
c) Continuous capillary
d) Discontinuous capillary

Answer 1

c) Continuous capillary

Question 2

What structure allows transcytosis in capillaries for macromolecules?
a) Tight junctions
b) Caveolae vesicles
c) Fenestrations
d) Paracellular clefts

Answer 2

b) Caveolae vesicles

Question 2

Bulk flow in capillaries is primarily dependent on the balance of which forces?
a) Diffusion gradients
b) Hydrostatic and oncotic pressures
c) Osmosis and active transport
d) Electrochemical gradients

Answer 2

b) Hydrostatic and oncotic pressures

Question 2

Which capillary type is specialized for rapid filtration such as in kidneys?
a) Continuous
b) Fenestrated
c) Sinusoidal
d) Discontinuous

Answer 2

b) Fenestrated

Question 2

Which of the following best describes paracellular transport?
a) Through fenestrations
b) Across endothelial cells via vesicles
c) Between endothelial cells through intercellular clefts
d) Active transport by pumps

Answer 2

c) Between endothelial cells through intercellular clefts

Question 2

Flow-limited substances in capillaries are mainly limited by:
a) Diffusion across endothelial cells
b) Blood flow rate
c) Vesicular transport capacity
d) Size of the molecule

Answer 2

b) Blood flow rate

Question 2

Diffusion-limited transport applies primarily to:
a) Small, lipid-soluble molecules
b) Large molecules and proteins
c) Oxygen and carbon dioxide
d) Electrolytes

Answer 2

b) Large molecules and proteins

Question 3

What happens to delivery of oxygen if blood flow to tissues is significantly reduced?
a) Oxygen delivery increases
b) Oxygen delivery decreases
c) Oxygen diffusion distance decreases
d) No change in oxygen delivery

Answer 3

b) Oxygen delivery decreases

Question 3

Capillary hydrostatic pressure (Pc) at the arteriolar end of a capillary is typically:
a) Higher than at the venular end
b) Lower than at the venular end
c) Equal to venular end
d) Negligible compared to oncotic pressure

Answer 3

a) Higher than at the venular end

Question 4

Which Starling force is primarily responsible for pulling fluid back into capillaries?
a) Capillary hydrostatic pressure
b) Interstitial hydrostatic pressure
c) Capillary oncotic pressure
d) Interstitial oncotic pressure

Answer 4

c) Capillary oncotic pressure

Question 5

What is the average value of capillary oncotic pressure in mmHg?
a) 15
b) 25
c) 10
d) 35

Answer 5

b) 25

Question 6

An increase in venous pressure will primarily cause:
a) Decreased capillary hydrostatic pressure
b) Increased capillary hydrostatic pressure
c) Increased interstitial oncotic pressure
d) Decreased capillary oncotic pressure

Answer 6

b) Increased capillary hydrostatic pressure

Question 6

How does vasodilation affect capillary hydrostatic pressure?
a) Decreases it
b) Has no effect
c) Increases it
d) Converts it to oncotic pressure

Answer 6

c) Increases it

Question 7

What pressure in the interstitial fluid is typically slightly negative in most loose tissues?
a) Interstitial hydrostatic pressure
b) Capillary hydrostatic pressure
c) Interstitial oncotic pressure
d) Capillary oncotic pressure

Answer 7

a) Interstitial hydrostatic pressure

Question 8

In edema, which Starling force is commonly increased, leading to fluid accumulation?
a) Capillary oncotic pressure
b) Interstitial oncotic pressure
c) Capillary hydrostatic pressure
d) Interstitial hydrostatic pressure

Answer 8

c) Capillary hydrostatic pressure

Question 9

The reflection coefficient represents:
a) Capillary permeability to water
b) Capillary permeability to proteins
c) Rate of vesicular transport
d) The hydrostatic pressure in capillaries

Answer 9

b) Capillary permeability to proteins

Question 10

Lymphatic vessels return excess interstitial fluid to the blood primarily due to:
a) Capillary hydrostatic pressure
b) Interstitial oncotic pressure
c) One-way flap valves and smooth muscle contraction
d) Venous valve function

Answer 10

c) One-way flap valves and smooth muscle contraction

Question 11

Which mechanism is quantitatively most important for movement of electrolytes across capillaries?
a) Diffusion
b) Bulk flow
c) Active transport
d) Vesicular transport

Answer 11

b) Bulk flow

Question 12

Which of the following decreases the rate of oxygen diffusion to tissues?
a) Arteriolar vasodilation
b) Increased arterial PO2
c) Increased number of flowing capillaries
d) Increased diffusion distance due to edema

Answer 12

d) Increased diffusion distance due to edema

Question 13

What does a higher postcapillary resistance relative to precapillary resistance cause?
a) Decreased capillary hydrostatic pressure
b) Increased capillary hydrostatic pressure
c) Reduced lymph flow
d) Reduced capillary permeability

Answer 13

b) Increased capillary hydrostatic pressure

Question 14

What happens to interstitial oncotic pressure when fluid is reabsorbed into capillaries?
a) It decreases
b) It increases
c) It remains the same
d) It becomes hydrostatic pressure

Answer 14

b) It increases

Question 15

Which statement about sinusoidal capillaries is true?
a) They have tight junctions and no gaps
b) They contain large gaps and fenestrations for cell passage
c) They are the most common type of capillary
d) They are impermeable to plasma proteins

Answer 15

b) They contain large gaps and fenestrations for cell passage

Question 16

What effect does increased capillary filtration constant (Kf) have on fluid exchange?
a) Decreases filtration
b) Increases filtration
c) No effect
d) Increases oncotic pressure

Answer 16

b) Increases filtration

Question 17

What is the typical net driving force (NDF) at the venular end of a capillary?
a) Positive, favoring filtration
b) Negative, favoring reabsorption
c) Zero, no fluid movement
d) Equal to hydrostatic pressure

Answer 17

b) Negative, favoring reabsorption

Question 18

External compression (e.g., compression stockings) decreases edema primarily by: a) Increasing capillary hydrostatic pressure b) Increasing interstitial hydrostatic pressure c) Decreasing lymph flow d) Decreasing capillary oncotic pressure

Answer 18

b) Increasing interstitial hydrostatic pressure

Question 19

Which capillary type(s) allow passage of red blood cells and large molecules? a) Continuous b) Fenestrated c) Sinusoidal d) None of the above

Answer 19

c) Sinusoidal (discontinuous)

Question 20

What is the major protein responsible for capillary oncotic pressure? a) Globulins b) Albumin c) Fibrinogen d) Hemoglobin

Answer 20

b) Albumin

Question 21

Which of the following would NOT increase edema formation? a) Increased venous pressure b) Decreased plasma protein concentration c) Increased lymphatic drainage d) Increased capillary permeability

Answer 21

c) Increased lymphatic drainage

Question 22

The net fluid movement outward from the capillaries is known as: a) Reabsorption b) Filtration c) Diffusion d) Transcytosis

Answer 22

b) Filtration

Question 22

Which of the following best describes the role of precapillary sphincters? a) Increase permeability of capillaries b) Regulate blood flow into capillaries c) Pump lymph through lymphatic vessels d) Control oxygen diffusion rate

Answer 22

b) Regulate blood flow into capillaries

Question 23

TRUE OR FALSE: Precapillary sphincters help regulate flow through the capillaries. Regulation occurs via contraction or dilatation A. the 1st statement is true B. the 2nd statement is true C. both statement is true D. both statement is false

Answer 23

C. both statement is true

Question 24

TRUE OR FALSE: Venules are the most muscular microcirculatory vessel

Answer 24

False they are arterioles

Question 24

TRUE OR FALSE: Low venous content indicates high arterial oxygen, high oxygen consumption, or low blood flow. O2 delivery is dependent on arterial blood flow and arterial O2 content A. the 1st statement is true B. the 2nd statement is true C. both statement is true D. both statement is false

Answer 24

B. the 2nd statement is true Low venous content: * low arterial oxygen * high oxygen consumption * low blood flow

Question 25

TRUE OR FALSE: Capillary hydrostatic pressure pushes water into of the capillaries. Interstitial hydrostatic pressure pushes substance into the interstitium A. the 1st statement is true B. the 2nd statement is true C. both statement is true D. both statement is false

Answer 25

D. both statement is false

Question 26

TRUE OR FALSE: Hydrostatic pressure is pressure due to water. Oncotic pressure is pressure due to proteins in a solution A. the 1st statement is true B. the 2nd statement is true C. both statement is true D. both statement is false

Answer 26

C. both statement is true

Question 27

TRUE OR FALSE: Increase in blood flow, increase the amount of substance being delivered in the tissue. Slower flow, increase the amount of substance being delivered in the tissue A. the 1st statement is true B. the 2nd statement is true C. both statement is true D. both statement is false

Answer 27

A. the 1st statement is true If the flow of blood is much less/ slower → deliver less of substance

Question 28

TRUE OR FALSE: More holes, faster bulk flow

Answer 28

True

Question 29

TRUE OR FALSE: Electrolytes and water are mainly transported in bulk flow

Answer 29

True

Question 30

Combination of transcellular & paracellular a. Active transport b. Vesicular transport c. Bulk flow d. Diffusion

Answer 30

c. Bulk flow

Question 31

Most important quantitatively a. Active transport b. Vesicular transport c. Bulk flow d. Diffusion

Answer 31

c. Bulk flow

Question 32

also known as Convection a. Active transport b. Vesicular transport c. Bulk flow d. Diffusion

Answer 32

c. Bulk flow

Question 33

applies mainly on O2, Co2, and lipid-soluble substances a. Active transport b. Vesicular transport c. Bulk flow d. Diffusion

Answer 33

d. Diffusion

Question 34

Driven by the balance of hydrostatic and osmotic pressures a. Active transport b. Vesicular transport c. Bulk flow d. Diffusion

Answer 34

c. Bulk flow

Question 35

for macromolecules a. Active transport b. Vesicular transport c. Bulk flow d. Diffusion

Answer 35

b. Vesicular transport

Question 36

Applies to substances that easily cross the capillary wall a. diffusion limited b. flow limited

Answer 36

b. flow limited

Question 37

main limiting factor: distance a. diffusion limited b. flow limited

Answer 37

a. diffusion limited

Question 38

amount that reaches the tissues is dependent on the amount of blood flow a. diffusion limited b. flow limited

Answer 38

b. flow limited

Question 39

applies to large molecules a. diffusion limited b. flow limited

Answer 39

a. diffusion limited

Question 40

Normal Arterial O2 Saturation: a. 95 mmHg PO2 or 97% Saturation b. 96 mmHg PO2 or 97% Saturation c. 97 mmHg PO2 or 98% Saturation d. 98 mmHg PO2 or 99% Saturation

Answer 40

a. 95 mmHg PO2 or 97% Saturation

Question 41

Normal Venous O2 Saturation: a. 35 mmHg PO2 or 70% Saturation b. 40 mmHg PO2 or 75% Saturation c. 45 mmHg PO2 or 80% Saturation d. 50 mmHg PO2 or 85% Saturation

Answer 41

b. 40 mmHg PO2 or 75% Saturation

Question 42

How does higher capillary oncotic pressure affect capillary absorption? a) Decreases it b) Has no effect c) Increases it d) Converts it to hydrostatic pressure

Answer 42

c) Increases it

Question 43

How does higher interstitial fluid affect reabsorption in the interstitium? a) Decreases it b) Has no effect c) Increases it d) Converts it to hydrostatic pressure

Answer 43

c) Increases it

Question 44

increased arteriolar pressure, _____ capillary hydrostatic pressure a. increase b. decrease c. no change

Answer 44

a. increase

Question 45

increased venous pressure, _____ capillary hydrostatic pressure a. increase b. decrease c. no change

Answer 45

a. increase

Question 46

increased oncotic pressure, _____ absorption a. increase b. decrease c. no change

Answer 46

a. increase

Question 47

TRUE OR FALSE: The net driving force (NDF) is (+) in the arteriolar end, thus there will be filtration or fluid will move out. The net driving force (NDF) is (-) in the venular end, thus there will be reabsorption or fluid will move in A. the 1st statement is true B. the 2nd statement is true C. both statement is true D. both statement is false

Answer 47

C. both statement is true

Question 48

TRUE OR FALSE: If σ is close to 1, then proteins cannot freely move in and out of the capillary. If σ is close to 0 = then proteins can freely move in and out of the capillary A. the 1st statement is true B. the 2nd statement is true C. both statement is true D. both statement is false

Answer 48

C. both statement is true

Question 49

increased capillary pressure, _____ arterial resistance a. increase b. decrease c. no change

Answer 49

b. decrease

Question 50

increased Plasma Oncotic Pressure, _____ Plasma proteins a. increase b. decrease c. no change

Answer 50

a. increase

Question 51

Net capillary fluid filtration is enhanced by: a. Decreased capillary oncotic pressure b. Decreased venous pressure c. Increased precapillary resistance d. Increased tissue hydrostatic pressure

Answer 51

a. Decreased capillary oncotic pressure

Question 52

capillary hydrostatic pressure = 15mmHg capillary oncotic pressure = 28mmHg interstitial hydrostatic pressure = -5mmHg tissue oncotic pressure = 6mmHg Assume that σ = 0, these Starling forces will result in: a. Net filtration b. Net reabsorption c. No net fluid movement

Answer 52

b. Net reabsorption

Question 53

A patient being treated for hypertension with an arterial vasodilator develops peripheral edema. The most likely cause of this edema is: A. Decreased capillary hydrostatic pressure B. Decreased capillary filtration constant C. Increased postcapillary/ precapillary resistance ratio D. Reduce venous pressure

Question 54

Hydrostatic pressure is for: A. Filtration B. Reabsorption

Answer 54

A. Filtration

Question 55

increased reflection coefficient, _____ protein leakage a. increase b. decrease c. no change

Answer 55

a. increase

Question 56

increased water, _____ hydrostatic pressure a. increase b. decrease c. no change

Answer 56

a. increase

Question 57

Oncotic pressure is for: A. Filtration B. Reabsorption

Answer 57

B. Reabsorption

Question 58

true or false: capillary hydrostatic pressure is more sensitive to venous pressure

Answer 58

True

Question 59

True or false: interstitial hydrostatic pressure is sub atmospheric

Answer 59

True - 2 mmHg, seen in rigid enclosed compartments (e.g. brain)

Question 60

Capillary hydrostatic pressure is higher at the ____ end A. Arterial B. Venous

Answer 60

A. Arterial

Question 61

Intersittial oncotic pressure is higher at the ____ end A. Arterial B. Venous

Answer 61

B. Venous

Question 62

increased interstitial hydrostatic pressure, _____ fluid on lymph vessel a. increase b. decrease c. no change

Answer 62

a. increase

Question 63

If there is (+) NDF, will there be a possibility of edema?

Answer 63

Yes