QuestionSBA
QuestionChoice
This is incorrect. The capillary hydrostatic pressure is the force coming from the heart contraction which drives fluid out of the capillary. Along the course of the capillary, this force drops significantly due to resistance in the vessel, meaning it is very small by the venous end of the capillary. Furthermore, if this force was significant, it would push fluid out of the capillary, whereas the question asked for the force driving the reabsorption of fluid back into the capillary.
10026322
c
Capillary hydrostatic pressure
QuestionChoice
Oncotic pressure is the osmotic force of large molecules, such as proteins, in a solution. The capillary oncotic pressure is therefore the force of large proteins within the capillary pulling fluid from the interstitium back into the capillary. At the arterial end of the capillary, the capillary hydrostatic force outweighs the capillary oncotic pressure, and hence fluid moves out into the interstitium. At the venous end of the capillary, however, the capillary hydrostatic force is much lower and hence the capillary oncotic pressure predominates, pulling fluid back from the interstitium into the capillary.
10026320
a
Capillary oncotic pressure
QuestionChoice
This is incorrect. Whilst this force does indeed aid in pushing fluid back into the capillary, it is insignificant in comparison to the size of the capillary oncotic pressure.
10026323
d
Tissue hydrostatic pressure
QuestionChoice
This is incorrect. It is the capillary oncotic pressure which primarily drives fluid reabsorption back into the capillary at the venous end.
10026324
e
None of the above
QuestionChoice
This is incorrect. The tissue oncotic pressure is essentially 0 in a healthy state as there shouldn't be any protein in the interstium. Furthermore, if this force was significant, it would pull fluid out of the capillary, whereas the question asked for the force driving the reabsorption of fluid back into the capillary.
10026321
b
Tissue oncotic pressure
Concept
Chapter
2693
3809
Structure and physiology of blood vessels
Topic
159
Cardiovascular physiology
17662
At the venous end of a capillary, the net movement of fluid is from the interstitium back into the capillary.

Which of the following is the predominant force driving this reabsorption?
a