vascular bio 1

Question 1

what are the tunics (layers) of blood vessels

Answer 1

tunica intima
tunica media
tunica adventitia (externa)

Question 2

what are the layers of the tunica intima?

Answer 2

endothelial layer
basal lamina
subendothelial layer

Question 3

what is present in the subendothelial layer of the tunica intima of arteries?

Answer 3

smooth muscle cells

Question 4

internal elastic lamina is present where? composed of what? what’s it’s purpose?

Answer 4

the INTERNAL ELASTIC LAMINA is present in the subendothelial layer of the tunica intima
it is composed of elastin
contains fenestrate for diffusion of substances

Question 5

tunica media components

Answer 5

smooth muscle with ELASTIC FIBERS, reticular fibers and proteoglycans
EXTERNAL ELASTIC LAMINA- also allows for passage of materials

Question 6

tunica adventicia

Answer 6

• external layer of blood vessels
• connective tissue layer
• has blood vessels that run along and thru the external elastic lamina of the tunica media to the outer layers of the tunica media providing blood supply to intermediate layers

Question 7

the EXTERNAL and INTERNAL parts of the blood vessel supplied by?

Answer 7

vaso basorum- external

blood in the interstitial part- internal

Question 8

when does a blood vessel need a vaso basorum?

Answer 8

if they are larger than 1mm in diameter

otherwise supported by internal blood via diffusion

Question 9

Do the arteries or the veins of the vasa vasorum extend deeper to the tunica intima?

Answer 9

the veins because there is less of a need for arteries to extend down that far with the blood supply running thru the lumen but do need to have a blood supply carried back to the venous system

Question 10

how is the vasa vasorum involved in atherosclerosis?

Answer 10

it contributes to the angiogenesis and inflammation of a diseased vascular wall (and intimal thickening)

Question 11

What occurs to the vasa vasorum when a person has syphilis?

Answer 11

• the vasa vasorum of the ascending aorta becomes inflamed which results in endardaritis and periarteritis of the vasa vasorum. They become obliterated eventually leaving some scarring and degeneration of the elastic lamellae
• scarring look like depressions that eventually have a TREE BARK APPEARANCE imprint on the intimal surface

Question 12

what is the main innervation of the blood vessels? what are the nerves called and where in the blood vessel do they lie?

Answer 12

• sympathetics with a few vascular beds with parasympathetics
• nerves called nervi vasorum or vascularis
• lie in the interface between the tunica adventitia and media to innervated the smooth muscle of the media without penetrating it (for arteries)
• slight penetration in veins

Question 13

Endothelial cells structure

Answer 13

• cells are long and flattened, situated in direction of flow
• they have intercellular junctions between cells and to the basal lamina

Question 14

how are things transported from the tunica intima to the outter layers of the blood vessels?

Answer 14

pinocytosis is heavily used

Question 15

when an increase in blood flow causes shear stress on a blood vessel, what occurs?

Answer 15

-endothelial cells hyperpolarize
-this info is sent to vascular smooth muscle via gap jxns
-CAUSES HYPERPOLARIZATION
= VASODILATION

Question 16

weibel-palade bodies

Answer 16

• bodies situated in the endothelial layer of blood cells

- contain von willebrand factor, plasminogen, IL8, P selectin (leukocyte transmission)

Question 17

what is the function of endothelial cells in the endothelial layer of the tunica intima?

Answer 17

• promote and inhibit coagulation-hemostasis-prostacyclin
• moderate smooth muscle activity- make endothelin and NO/prostacyclin
• regulate inflammatory cell traffic- materials from lumen to outer layers of the vessels
• transport pinocytotic vesicles
• regulate angiogenesis

Question 18

endothelin

Answer 18

made by endothelial cells

vasoconstrictor

Question 19

NO

Answer 19

made by enothelial cells

vasodilator

Question 20

prostacyclin

Answer 20

made my endothelial cells and is a vasodilator and a blood thinner

Question 21

endothelin

Answer 21

vasodilator made my endothelial cells

Question 22

Large (elastic) arteries (characteristics)

Answer 22

• lots of elastic lamellae that increase with age
• SM and Elastic lamellae layers are alternating in the tunica media
• lots of smooth muscle
• aging also causes mild-moderate intimal fibrosis (thickening)

Question 23

how does Marfan’s affect large arteries

Answer 23

• severe elastic fragmentation

Question 24

arteries vs veins

Answer 24

arteries- have larger tunica media with PROMINANT internal/ external elastic membranes,
venous- smaller tunica media and No elastic membrane, thick tunica advantitia

Question 25

in terms of large (elastic) arteries, what changes with age?

Answer 25

• fibrosis of the intimal layer
• increase in elastic lamellae (also SM) in the tunica media
• fragmentation of the elastic lamellae

Question 26

muscular artery

Answer 26

• has less elastic lammelae and more SM in tunica media
• have prominent internal/external elastic membrane
• intimal fibrosis occurs with age

Question 27

metarterioles

Answer 27

• vessels between arterioles and capillaries
• regulate flow from arterioles to capillaries via a sphincter mechanism (relaxed, blood flow to the microcirc/contracted stopped)

Question 28

capillaries-layers

Answer 28

tunica intima
tunica media absent- pericytes instead
tunica adventitia absent

Question 29

what are the three types of capillaries

Answer 29

continuous
fenestrated
sinusoidal

Question 30

pericytes

Answer 30

• contractile
• responsible for scarring of the CNS
• replace the tunica media in capillaries
• can TRANSFORM INTO SMOOTH MUSCLE CELLS AND FIBROBLASTS

Question 31

arteriole

Answer 31

• main resistance vessels
• determine how much blood will flow downstream
• 1:1 lumen to wall thickness

Question 32

microcirculation

Answer 32

circulation between arterioles to venuoles