Lecture 19 and 20

Question 1

What are the 4 primary forces driving fluid exchange across the capillary membrane?

Answer 1

1. Capillary hydrostatic pressure
2. Interstitial fluid colloid osmotic pressure (oncotic pressure)
3. Interstitial fluid hydrostatic pressure
4. Capillary colloid osmotic pressure (oncotic pressure)

Question 2

Capillary hydrostatic pressure:

a. causes osmosis into capillary
b. is normally, close to zero
c. tends to force fluid outward through the capillary membrane.
d. two of the above

Answer 2

c. tends to force fluid outward through the capillary membrane.

Question 3

Interstitial fluid colloid osmotic pressure:

a. is normally, close to zero
b. tends to force fluid outward through the capillary membrane.
c. causes osmosis out of the capillary
d. two of the above

Answer 3

c. causes osmosis out of the capillary

Question 4

Interstitial fluid hydrostatic pressure:

a. causes osmosis out of the capillary
b. is normally, close to zero
c. causes osmosis into of the capillary
d. two of the above

Answer 4

b. is normally, close to zero

Question 5

Capillary colloid osmotic pressure:

a. causes osmosis into capillary
b. causes osmosis out of the capillary
c. tends to force fluid outward through the capillary membrane.
d. two of the above

Answer 5

a. causes osmosis into capillary

Question 6

Capillary and interstitial fluid colloid osmotic pressure is determined primarily by _______ ________.

Answer 6

protein concentration (oncotic pressure)

Question 7

The balance of the 4 primary driving force pressures determines ______ filtration pressure and movement of fluid.

Answer 7

net

Question 8

T or F? At the venous side of capillaries, net filtration is favored; at arterial side of capillaries, net reabsorption is favored.

Answer 8

False, opposite is true.

Question 9

What is the primary reason why net filtration and net reabsorption is different for the arterial side and venous side?

Answer 9

There is a difference in capillary hydrostatic pressure between the arterial end and venous end of the capillary.

Question 10

Which end has a higher hydrostatic pressure at the capillaries?

Answer 10

Arterial end (15-25 mmHg difference)

Question 11

The ____ ______ carries away any remaining fluid in the interstitium.

Answer 11

lymphatic system

Question 12

What can occur if the rate of fluid that enters the interstitium is greater than what the lymphatic system can remove?

Answer 12

Edema

Question 13

Edema can be related to which of the following:

a. Increased capillary hydrostatic pressure
b. Increased capillary permeability
c. Decreased plasma oncotic pressure
d. Lymphatic obstruction
e. All of the above

Answer 13

e. All of the above. Every cause of edema can be related to one or more of the following.

Question 14

What are the driving forces moving fluid outward?

Answer 14

1. Capillary hydrostatic pressure

2. Interstitial fluid colloid osmotic pressure

Question 15

What are the driving forces moving fluid inward?

Answer 15

1. Capillary colloid osmotic pressure

2. Interstitial fluid hydrostatic pressure

Question 16

Higher filtration at the arterial end of capillary vs less reabsorption at the venous end results in _______.

Answer 16

Net fluid loss.

Question 17

Why doesn’t fluid accumulate in interstitial space if filtration pressure exceeds reabsorption in this case (under normal conditions)?

Answer 17

9/10 of fluid that is filtered out of capillary is reabsorbed and 1/10 of fluid that is filtered out of capillary is returned to circulation via the lymphatic system.

Question 18

How much fluid is returned to circulation via lymphatic system each day?

Answer 18

2-3 L/day (2 ml/min)

Question 19

What happens to the proteins that leak out of capillaries?

Answer 19

It is put back into circulation via the lymphatic system.

Question 20

What factors affect lymph flow?

Answer 20

Interstitial fluid pressure and activity of lymphatic pump.

Question 21

T or F? As interstitial fluid pressure rises, lymph flow increases.

Answer 21

True

Question 22

How is the flow of lymph through the lymphatic system achieved?

Answer 22

By activities of the lymphatic pump; contraction of muscles surrounding lymph vessels and movement of body parts—increase lymph flow.