CH 21 - Blood Vessels and Circulation

Question 1

What makes up the tunica intima?

Answer 1

Endothelium
Basement membrane
Lamina propria
Internal elastic membrane (fenestrated)

Question 2

What makes up the tunica media?

Answer 2

Smooth muscle cells

External elastic membrane (fenestrated)

Question 3

What makes up the tunica externa/adventitia?

Answer 3

Connective tissue

Question 4

Why do smaller vessels have less layers?

Answer 4

So gases can diffuse easily

Question 5

Name and briefly describe the 3 types of ateries.

Answer 5

Elastic/conducting - largest diameters, controls pressure levels

Muscular - thick tunica media allows vessels to regulate blood supply by constricting/dilating

Arterioles - transport blood from small arteries to capillaries, smallest artery where all 3 tunics can be differentiated, vasoconstriction/dilation

Question 6

What is a capillary wall made of?

Answer 6

Endothelium, basement membrane, loose CT layer

Question 7

How do substances move through capillaries?

Answer 7

Diffusion

Lipid-soluble and small water-soluble molecules pass through plasma membrane

Large water-soluble molecules pass through fenestrations

Red blood cells flow through one at a time to allow for exchange

Question 8

Describe continuous capillaries.

Give an example.

Answer 8

No fenestrations, less permeable to large molecules

Muscle, nervous tissue

Question 9

Describe fenestrated capillaries.

Give an example.

Answer 9

Endothelial cells have numerous fenestrae, highly permeable

Intestinal villi, choroid plexus, glomeruli of kidney

Question 10

Describe sinusoid capillaries.

Give an example.

Answer 10

Large diameter, sparse basement membrane, large molecules can move across

Liver, bone marrow

Question 11

Describe venous capillaries.

Give an example.

Answer 11

Larger than sinusoids

Spleen