Capillaries

Question 1

Carry blood from where?

Answer 1

Arterioles to organs and allow oxygen to diffuse from the blood into the organ

Question 2

Muscle layer?

Answer 2

No muscle layer

Question 3

Elastic layer?

Answer 3

no elastic layer

Question 4

Valves?

Answer 4

No valves

Question 5

Cell wall thickness?

Answer 5

One cell thick cell wall

Question 6

Lumen size?

Answer 6

Very small lumen

Question 7

4 ways in which the capillaries are adapted to act as an exchange surface?

Answer 7

Permeable wall
Thin walls (one cell thick)
Flat endothelial cells
Narrow lumen
Red blood cells pass singly

Question 8

How does the structure of capillaries enable them to function efficiently as exchange surfaces?

Answer 8

1) fenestrations between the cells so large molecules can pass through
2)thin walls- short diffusion distance pathway
3) narrow lumen- reduced blood flow- more time for diffusion