vascular endothelium

Question 1

what % of all endothelial cells reside within vasculature

Answer 1

98%

Question 2

what is the basic structure of blood vessels

Answer 2

3 layers
tunica adventitia: vasa vasorum, nerves
tunica media: smooth muscle cells
tunica intima: endothelium, basement membrane, lamina propria and internal elastic membrane

Question 3

what are capillaries and venules

Answer 3

endothelium supported by mural cells (pericytes) and basement membrane

Question 4

what takes place in the capillaries

Answer 4

where exchanges of nutrients and oxygen between blood and tissues occur

Question 5

what is another function of microvascular endothelium

Answer 5

promotes tissue haemostasis

damage to endothelium can cause organ dysfunction

Question 6

what is required for maintenance of tissue homeostasis and organ regeneration

Answer 6

angiocrine factors in microvascular endothelium

Question 7

why does dysfunctional endothelium contribute to disease more than any other organ

Answer 7

contribute to components of:
ischaemia
chronic inflammatory diseases
cancer
diabetes

Question 8

basic function of endothelium

Answer 8

acts as vital barrier separating blood from tissues
very extensive surface area
endothelial cells are very flat 1-2ym thick
formed by monolayer of endothelial cells
cells regulate essential functions of blood vessels

Question 9

what are the multiple functions of blood vessels and tissues that endothelium controls

Answer 9

tissue homeostasis and regeneration
permeability
vascular tone
angiogenesis
inflammation
haemostasis and thrombosis

Question 10

what is meant by endothelial cells are hetergenous

Answer 10

their function and phenotype depends on their location

Question 11

what happens in resting endothelium

haemostasis

Answer 11

anti inflammatory, anti thrombotic, anti proliferative is balanced with pro inflammatory, pro thrombotic, pro angiogenic

Question 12

what causes endothelium to be activated

risk factors:

Answer 12

inflammation - proinflammatory cytokines
hypercholesterolaemia
sex hormonal imbalance
ageing
mechanical stress
viruses
smoking
oxLDL 
high bp
high glucose

Question 13

what does activated endothelium initially cause over time

Answer 13

thrombosis
senescence - stress
permeability
leukocyte recruitment
ALL these factors lead to ATHEROSCLEROSIS

Question 14

how does fatty-streak formation occur in atherosclerosis

Answer 14

smooth muscle migration
foam cell formation
t cell activation
adherence and aggregation of platelets
adherence and entry of leukocytes

Question 15

how is advanced complicated lesion of atherosclerosis formed

Answer 15

macrophage accumulation
formation of necrotic core
fibrous cap formation
angiogenesis

Question 16

where do leukocytes gets stuck after endothelial activation

Answer 16

in sub endothelial space

they then differentiate into macrophages and become foam cells

Question 17

what does increased membrane permeability cause

Answer 17

leakage of plasma proteins through junctions into subendothelial space

Question 18

why do atherosclerotic plaques occur preferentially at birfurcations and curvatures of vascular tree

Answer 18

flow patterns and haemodynamic forces are not uniform in vascular system and irregular distribution of low wall sheer stress

Question 19

what does laminar blood flow promote

Answer 19

anti thrombotic, anti inflammatory factors
endothelial survival
inhibition of smooth muscle cell proliferation
nitric oxide production

Question 20

what does disturbed blood flow promote

Answer 20

thrombosis, inflammation (leukocyte adhesion)
endothelial apoptosis
smc proliferation
loss of nitric oxide production

Question 21

what are some of the protective effects nitric oxide has on vascular endothelium

Answer 21

reduces oxidation of ldl cholesterol
dilates blood vessels
reduces platelet activation
inhibits monocyte adhesion
reduces proliferation of smc in vessel wall
reduces release of superoxide radical

Question 22

what is angiogenesis

Answer 22

formation of new blood vessels by sprouting from existing vessels

Question 23

what is angiogenesis essential for

Answer 23

embryonic development
wound healing
menstrual cycle

Question 24

how does angiogenesis lead to atherosclerosis

Answer 24

promotes plaque growth

Question 25

when can angiogenesis be useful in cvd

Answer 25

therapeutic angiogenesis prevents damage post -ischaemia

Question 26

what is thromboinflammation

Answer 26

loss of normal antithrombotic and anti imflammatory functions of endothelial cells causing thrombosis with associated inflammation

Question 27

what is link between covid 19 and endothelium

Answer 27

covid 19 causes endothelial cell dysfunction:
bleeding/dysfunction
inflammation
permeability/barrier
vascular tone
redox balance

Question 28

what are the sequence of events in cov2 infection and endothelial cells that leads to severe cov2

Answer 28

infection
cytokine storm
endothelial activation
procoagulant switch

Question 29

what is another possible mechanisms of cov2 on endothelium

Answer 29

cov2 enters endothelial cell and causes direct damage

Question 30

what processes cause early development of atherosclerotic plaques

Answer 30

endothelial activation
permeability
leukocyte adhesion

Question 31

physiologically in which vessels does leukocyte transmigration occur

Answer 31

post capillary venules

Question 32

where do majority of endothelial cells occur

Answer 32

capillaries