lll

Question 1

types of capillaries

Answer 1

continuous, fenestrated and sinusoids

Question 2

continuous capillaries

Answer 2

Have complete endothelial lining; found in all tissues except epithelia and cartilage
their fxn:
1. Permit diffusion of water, small solutes, and lipid-soluble materials
2. Block blood cells and plasma proteins
c. Specialized Continuous
1. in CNS and thymus
2. very restricted permeability ( i.e., the blood–brain barrier)

Question 3

fenestrated capillaries

Answer 3

a.pores in endothelial lining
b. rapid exchange of water and larger solutes between plasma and
interstitial fluid
c. found in choroid plexus, endocrine organs, kidneys, intestinal tract

Question 4

sinusoids

Answer 4

a. Have gaps between adjacent endothelial cells
b. free exchange: water and large plasma proteins between blood and
interstitial fluid; slow flow
c. Phagocytic cells monitor blood at sinusoids
d. liver, spleen, bone marrow, endocrine organs

Question 5

capillary beds

Answer 5

Connect one arteriole and one venule
2. controlled by smooth muscle segments (metarterioles)

Question 6

Collaterals

Answer 6

1. multiple arteries that contribute to one capillary bed
2. allow circulation if one artery is blocked
3. Arterial anastomosis (fusion of two collateral arteries that supply a bed

Question 7

Arteriovenous Anastomoses

Answer 7

1. direct connections between arterioles and venules
2. bypass the capillary bed

Question 8

Capillary sphincter

Answer 8

1. at entrance to each capillary; opens and closes, causing capillary blood to flow in
   pulses
2. Vasomotion
   a. contraction and relaxation cycle of capillary sphincters
   b. causes blood flow in capillary beds to constantly change routes

Question 9

interstitial/ Lymph fluid

Answer 9

a. hydrostatic pressure- forces water/solutes out of capillary
b. osmotic pressure-forces water/solutes into capillary
c. capillary vs. interstitial fluid
d. capillaries filter out more than they reabsorb
e. excess goes into lymph system