Lecture 8: Capillary flow and pressure

Question 1

How many capillaries are there per gram of skeletal muscle?

Answer 1

500,000

Question 2

What percentage of capillaries arounnd skeletal muscle are perfused at rest?

Answer 2

20-25%

Question 3

How are endothelial cells in capillaries connected?

Answer 3

Interendothelial junctions

Question 4

What surrounds endothelial cells in a capillary?

Answer 4

The basement membrane

Question 5

What are capillaries permeable to?

Answer 5

O₂ and CO₂

Most are also permeable to water and crystalloids?

Question 6

How does water enter capillaries?

Answer 6

Aquaporins (AQP1)

Between cells

Question 7

How do crystalloids enter capillaries?

Answer 7

Between endothelial cells

Question 8

What are capillaries impermeable to?

Answer 8

Colloids such as plasma proteins

Question 9

What are the 3 groups of capillaries?

Answer 9

1. Continuous capillaries
2. Fenestrated capillaries
3. Sinusoidal (discontinuos)

Question 10

What is the most common type of capillary?

Answer 10

Continuous

Question 11

Decribe the structure of a continuous capillary

Answer 11

Interendothelial junctions 10-15nm wide that allow relatively free passage of water and ions, except in theh brain and testes where there are narrower junctions

Question 12

Describe the structure of fenestrated capillaries

Answer 12

Conatain fenestrae (windows) throughout cells to allow diffusion through as well as between cells

Question 13

Where are fenestrated capillaries located?

Answer 13

Epithelia such as the small intestine and glands