Vessels

Question 1

what do blood vessels do?

Answer 1

• help w movement of blood form heart to periphery and back
• resist pressure from heart
• prevent backflow when pressure drops
• provide transport to and from tissue, then to and from lumen of vessel
• regulate & respond to changes in pressure

Question 2

what are the major differences between arteries, veins, and capillaries?

Answer 2

• arteries = thick walls, smaller lumen
• veins = thinner walls, bigger lumen, valves
• capillaries = thinnest walls for gas exchange

Question 3

describe the 3 layers of blood vessels

Answer 3

1) tunica intima (inner) = lining endothelium continuous with endothelium of heart, subendothelial CT, internal elastic lamina
2) tunica media (middle) = smooth muscle
3) tunica adventitia (outer) = dense/elastic CT; support

Question 4

what are the 2 types of autoregulation?

Answer 4

1) myogenic = intrinsic contractile response of smooth muscle when stretched
2) metabolic

Question 5

how can you tell the difference between an artery and a vein?

Answer 5

• arteries have thicker tunica media, thinner adventitia

- veins have thinner tunica media, and thicker adventitia, contains valves

Question 6

how are new blood vessels formed?

Answer 6

• vasculogenesis = during development

- angiogenesis = response to injury or cancer

Question 7

why does the aorta not have any valves?

Answer 7

high pressure vessel

Question 8

what is another name for aorta and the vena cava?

Answer 8

elastic artery/vein = substantial elastic fibers in tunica media

Question 9

what is present in the medium artery that is lost in the medium vein?

Answer 9

internal elastic lamina

Question 10

what are the features of small artery/vein and arteriole/venule?

Answer 10

• NO or minimal elastic lamina for small vessels

- NO elastic lamina for arteriole/venule

Question 11

what are the tunica media layers of small vessels?

Answer 11

• small artery = 2-4
• small vein = 1-2
• arteriole = 1-2
• venule = 0

Question 12

what are the 3 types of capillaries?

Answer 12

• continuous = tight junctions
• fenestrated = more movement across cell
• discontinuous = aka sinusoid; found in liver and spleen

Question 13

what moves things across capillaries that cannot fit through fenestrations?

Answer 13

pinocytotic vesicles

Question 14

name something that differentiates lymph vessels from blood vessels

Answer 14

no RBCs in lymph vessel lumen

Question 15

what do lymph vessels and veins have in common?

Answer 15

valves

Question 16

what is vasa vasorum?

Answer 16

• small blood vessels found in the tunica adventitia of large arteries/veins
• provides nutrients and remove waste from outermost layers of vessels with the thickest walls
• *any blood vessel in tunica adventitia is part of vasa vasorum

Question 17

what are characteristics of discontinuous capillaries?

Answer 17

• incomplete basement membrane
• bigger pores / fenestrations
• bigger intercellular cleft