Vascular Endothelium

Question 1

What are the layers of blood vessels (except capillaries and venules)?

Answer 1

tunica adventitia
tunica media
tunica intima

Question 2

What is in the tunica adventitia?

Answer 2

vaso vasorum

nerves

Question 3

What is in the tunica media?

Answer 3

smooth muscle cells

Question 4

What is in the tunica intima?

Answer 4

endothelium

Question 5

Capillaries and venules are formed only by _________ supported by some _____ and a _______.

Answer 5

endothelium
pericytes (mural cells)
basement membrane

Question 6

Capillaries is where what occurs?

Answer 6

exchange of nutrients and oxygen between blood and tissue

Question 7

Microvascular endothelium promotes?

Answer 7

tissue homeostasis

Question 8

Damage to the endothelium can cause? List examples

Answer 8

organ dysfunction e.g. ischaemia, chronic inflammatory diseases, cancer, diabetes

Question 9

Microvascular endothelium is the source of what factors required for tissue homeostasis and organ regeneration?

Answer 9

angiocrine

Question 10

What does organotypic properties mean?

Answer 10

tissue specific, heterogenous

Question 11

Endothelial cells lining the vascular system

Answer 11

SA >1000m^2, >100g, v flat, 1-2 µm thick and 10-20 µm in diameter, formed by a monolayer of endothelial cells, one cell deep (contact inhibition)

Question 12

Describe the proliferation rate of endothelial cells in vivo.

Answer 12

low

Question 13

What functions of blood vessels and tissues does the endothelium control?

Answer 13

vascular tone
angiogenesis
haemostasis and thrombosis
inflammation
permeability

Question 14

What factors are produced from the endothelial cells for angiogenesis?

Answer 14

matrix products: fibronectin, laminin, collagen, proteoglycans, proteases
growth factors: insulin like GF, transforming GF, colony stim. factor

Question 15

What factors are produced from the endothelial cells for inflammation?

Answer 15

adhesion molecules: ICAMs, VCAM, selectins

inflammatory mediators: IL1/6/8, leukotrienes, MHCII

Question 16

What factors are produced from the endothelial cells for vascular tone/permeability?

Answer 16

vasodilators: NO, prostacyclin
vasoconstrictors: ACE, thromboxane A2, leukotrienes, free radicals, endothelin

Question 17

What antithrombotic factors are produced from the endothelial cells for thrombosis/haemostasis?

Answer 17

prostacyclin, thrombomodulin, antithrombin, plasminogen activator, heparin

Question 18

What procoagulant factors are produced from the endothelial cells for angiogenesis?

Answer 18

VWF, thromboxane A2, thromboplastin, factor V, platelet activating factor, plasminogen activator inhibitor

Question 19

factors contributing to atherosclerosis

Answer 19

viruses
smoking
mechanical stress
inflammation
hypertension
OxLDL
high glucose
sex hormon imbalance
ageing

Question 20

Endothelial dysfunction in atherosclerosis

Answer 20

increased permeability to lipoproteins and other plasma constituents, up-regulation of leukocyte/endothelial adhesion molecules, migration of leukocytes into the artery wall

Question 21

Briefly outline pathogenesis of atherosclerosis.

Answer 21

1. Endothelial dysfunction in atherosclerosis
2. fatty streak formation
3. formation of an advanced, complicated lesion of atherosclerosis

Question 22

What happens during fatty streak formation?

Answer 22

smooth muscle migration, foam cell formation, adherence/aggregation of platelets

Question 23

What happens during formation of an advanced, complicated lesion of atherosclerosis?

Answer 23

macrophage accumulation
formation of a necrotic core
fibrous cap formation
angiogenesis

Question 24

Endothelial dysfunction in the pathogenesis of atherosclerosis: mechanisms

Answer 24

leukocyte recruitment,

permeability, shear stress, angiogenesis

Question 25

Describe the leukocyte adhesion cascade.

Answer 25

capture, rolling + activation, arrest, adhesion, intravascular crawling, paracellular + transcellular transmigration

Question 26

Recruitment of blood leukocytes into tissues normally takes place during?

Answer 26

inflammation

Question 27

Leukocytes adhere to the endothelium of ______________ and transmigrate into tissues.

Answer 27

post-capillary venules

Question 28

compare structure of capillaries and post capillary venules

Answer 28

post-capillary venules have more pericytes

Question 29

In atherosclerosis, leukocytes adhere to activated endothelium of _______ and get stuck in the subendothelial space

Answer 29

large arteries

Question 30

_______ migrate into the subendothelial space, differentiate into __________ and become foam cells.

Answer 30

Monocytes | macrophages

Question 31

Increased permeability results in _____________ through the junctions into the subendothelial space.

Answer 31

leakage of plasma proteins

Question 32

describe lipoprotein trapping/modification

Answer 32

lipoprotein leak out > bind to proteoglycans > become oxidated > join macrophage to form foam cells

Question 33

Atherosclerotic plaques occur preferentially at ________ and _________ of the vascular tree

Answer 33

bifurcations and curvatures

Question 34

Why does atherosclerosis occur at branch points?

Answer 34

flow patterns and hemodynamic forces are not uniform in the vascular system

Question 35

How does blood flow affect stress?

Answer 35

straight parts > laminar flow > high, directional stress | branches/curvatures > flow disturbed > irregular distribution of low wall shear stress

Question 36

Laminar blood flow promotes?

Answer 36

anti-thrombotic, anti-inflammatory factors endothelial survival Inhibition of SMC proliferation Nitric oxide (NO) production

Question 37

Disturbed blood flow promotes?

Answer 37

Thrombosis, inflammation (leukocyte adhesion) endothelial apoptosis SMC proliferation Loss of Nitric oxide (NO) production

Question 38

List protective effects of nitric oxide (NO) on the vascular endothelium.

Answer 38

vasodilator, reduces platelet activation, inhibits monocyte adhesion, reduces SMC proliferation, reduce release of superoxide radicals, reduces oxidation of LDL cholesterol

Question 39

define angiogenesis

Answer 39

formation of new vessels by sprouting from existing vessels

Question 40

outline the cascade of events that leads to angiogenesis

Answer 40

hypoxia > EC receptor binding > activation > proliferation > directional migration > ECM remodelling > tube formation > loop formation > vascular stabilisation

Question 41

Angiogenesis is essential for?

Answer 41

embryonic development, wound healing, menstrual cycle

Question 42

pathological angiogenesis promotes?

Answer 42

plaque growth

Question 43

therapeutic angiogenesis prevents?

Answer 43

damage post ischaemia