Vascular Endothelium

Question 1

basic structure of blood vessels

Answer 1

Tunica adventitia
Tunica media
Tunica intimia

Question 2

vasa vasorum

Answer 2

Tiny vessels that feed larger vessels

Question 3

structure of capillaries and venules

Answer 3

endothelium
mural cells (pericytes) 
basement membrane

Question 4

function of the microvascuar endothelium

Answer 4

promotes tissue homeostasis

Question 5

what is microvascular endothelium a source of

Answer 5

angiocrine factors - tissue homeostasis and organ regeneration

Question 6

examples of tissue specific (organotypic) variations of microvasculature

Answer 6

fenestrated - kidney
non-fenestrated - lung, skin, muscle, BBB
dicontinuous - liver

Question 7

properties of endothelial cells

Answer 7

flat
large surface area
one cell deep monolayer

Question 8

what is contact inhibition

Answer 8

cell junctions allow communication and information to tell adjacent cells to stop growing and form a monolayer

Question 9

functions of blood vessels

Answer 9

vascular tone
angiogenesis
tissue homeostasis
haemostasis
permeability
inflammation

Question 10

what is produced by endothelial cells for angiogenesis

Answer 10

matrix products e.g collagen

growth factors

Question 11

what is produced by endothelial cells for haemostasis

Answer 11

antithrombotic factors

procoagulant factors

Question 12

what is produced by endothelial cells for inflammation

Answer 12

adhesion molecules

inflammatory mediators

Question 13

what is produced by endothelial cells for vascular tone

Answer 13

vasodilator factors - NO, prostacyclin

vasoconstrictor factors - thromboxane A2, ACE

Question 14

what factors can activate the endothelium

Answer 14

smoking
viruses
mechanical stress
inflammation
high BP
oxidated LDL
highglucose

Question 15

stimuli for athersclerosis

Answer 15

hypercholesterolaemia
DM
hypertension
sex hormone imbalance - menopause
ageing
oxidative stress
proinflammatory cytokines
infectious agents
environmental toxins - smoking
disturbed blood flow

Question 16

steps of leukocyte adhesion cascade

Answer 16

rolling
activation
arrest
adhesion
transmigration

Question 17

Where does recruitment of leukocytes occur in atherosclerosis

Answer 17

leukocytes adhere to activated endothelium of large arteries (not post-capillary venules) and get stuck in subendothelial space
monocytes migrate into the subendothelial space, differentiate into macrophages and become foam cells

Question 18

4 mechanisms that contribute to the formation of atherosclerotic plaques

Answer 18

Leukocyte recruitment
Permeability
Shear stress
Angiogenesis

Question 19

how does vascular permeability end up in athersclerosis

Answer 19

Increased permeability results in leakage of plasma proteins through the junctions into the subendothelial space

Question 20

role of vascular permeability in athersclerosis

Answer 20

lipoproteins pass through leaky junctions into subendothelial space
oxidated by proteoglycans
macrophages inglobinate these and become foam cells
increased permeability allows this to occur

Question 21

what is fatty streak formation

Answer 21

follows after endothelial dysfunction

macrophage foam cells filled with oxidated lipoproteins

Question 22

where does athersclerosis happen and why

Answer 22

branch points

shear stress- flow patterns arent uniform so promotes inflammation

Question 23

how is non-laminar flow harmful

Answer 23

thrombosis and inflammation - leukocyte recruitment
endothelial apoptosis
smooth muscle cell proliferation
loss of NO production

Question 24

how is nitric oxide protective (6)

Answer 24

reduces lipoprotein oxidation
dilates vessels
reduces platelet activation
reduces free radicals
inhibits leukocyte recruitment
reduces proliferation of SMCs

Question 25

how is angiogenesis both harmful and protective

Answer 25

promotes plaque growth

but prevents damage post ischaemia