vascular epithelium

Question 1

what are the three layers of cells lining vessels other than capillaries?

Answer 1

tunica adventitia (think adventures= outdours- extenrla layer) = nerves
tunica media: smooth muscle cells
tunica intima: endothelium

Question 2

how small are caps compared to hair

Answer 2

1/ of hair in width

Question 3

what is the structure of capillaries

Answer 3

mainly endothelium supported by mural cells (pericytes) and a basement membrane

Question 4

what happens in capillaries

Answer 4

exchange of oxygen and nutrients with tissues

Question 5

How well spread/ distributed are capillaries?

Answer 5

almost every cell in body is in contact with microvascular endothelial cells

Question 6

in what vessel type do the majority of the endothelial cells reside?

Answer 6

98% in microvasculature

Question 7

how do the endothelial cells know that they are supposed to form monolayers and not stack onto eachother?

Answer 7

due to a phenomenon called contact inhibition, when they meet eachother at junctions signals are released that stop them from proliferating further

Question 8

what is the proliferation rate of endothelial cells? (not in number just word) when is an exception?

Answer 8

dont proliferate much in vivo, only when angiogenesis

Question 9

what are some of the fucntions of blood vessels that endothelium controls?

Answer 9

permeability
angiogenesis
haemostasis and thrombosis
INFLAMMATION
VASCULAR TONE (ud think this is only muscles buttt actuallyyy its not!)

Question 10

how do endothelial cells control all thesevascular functions?

Answer 10

by cytokines and factors see slide 11

Question 11

in what aspects do endothelial cells differ in different organs?

Answer 11

structure
function
molecular differences

Question 12

how is it possible for endothelial cells to be organotypic (differ amongst organs)

Answer 12

although same dna as all cells, different expression profiles: meaning different rnas

Question 13

how is the genetic profile of different endothelial types unalysed studied and presented?

Answer 13

by rna sequencing (since rna is what guides protein synth so is dif in each type) that is presented in Seurat Cluster graphs- each dot i a cell - each cluster of dots is an endoth cell type

Question 14

what is the human cell atlas

Answer 14

1) international collaborative consortium

2) charts cel types in the healthy body

3) from development to adulthood

Question 15

how do endothelial cells become tissue specific

Answer 15

tissue specific MICROENVIRONMENT influences phenotype of endothelial cells

tissue specific endothelial cells produce different angiocrine factors which are ESSENTIAL for

tissue homeostasis and regeneration

Question 16

what is the most abundant cell type in the heart?

Answer 16

endothelial cell

(Then its cardiomyocytes and then stromal cells)

Question 17

what two cell type sin the heart communicate and what is the term used to describe this communication?

Answer 17

cardiomyocytes and endothelial cells crosstalk!

Question 18

what is the most common type of angiogenesis in adults (meaning not part of development) called?

Answer 18

sprouting angiogenesis

Question 19

define angiogenesis

Answer 19

formation of neo-vessels FROM PRE-EXISTING blood vessels

Question 20

describe the cascade of events in angiogenesis

Answer 20

1) hypoxia causes angiogenic factor production
2) release of angiogenic factor and binding on endothelial cell receptor
3) endothelial cell activation and proliferation
4) directional migration of endothelial cells (towards new vessel)
5) ECM remodelling
6) tube formation and loop formation
7) vascular stabilisation

Question 21

what role do transcription factors play in angiogenesis?

Answer 21

regulate the precise temporal and spatial co-ordination of the expression of multiple genes during angiogenesis

Question 22

what are some physiological processes that involve angiogenesis

Answer 22

1) development
2) menstrual cycle
3) wound healing

Question 23

what are 2 crucial pathologies that involve angiogenesis?

Answer 23

cancer
atherosclerosis

Question 24

what is the angiogenic switch in cancer?

Answer 24

when a tumour grows to the point where the inner part cant get enough blood by diffusion from host vessels anymore so the hypoxia in the inner part of the tumour leads to the release of angiogenic and thus new vessels grow.

Question 24

some other pathologies that involve angiogenesis?

Answer 24

retinopathies
chronic inflammatory diseases
ischemic diseases
vascular malformations

Question 24

in what ways is this angiogenesis in tumours a bad thing?

Answer 24

facilitates tumour growth and metastasis

Question 25

how does angiogenesis influence cancer treatment?

Answer 25

anti-angiogenic drugs in clinic given in combination with chemotherapy for a number of solid tumors

Question 26

what is the difference between haemostasis and thrombosis

Answer 26

haemostasis is NORMAL blood clotting in response to INJURY

thrombosis is EXCESSIVE and/or SPONTANEOUS clot formation

Question 27

why may vessels’ role in control of bleeding only recently have been considered?(thrombosis, haemostasis ect)

Answer 27

because theres no numercal test you can do to measure/ separate the role of endothelium separate to blood

Question 28

what is a common way in which VWD presets?

Answer 28

in dentist by small bleeds

Question 29

what are the 2 treatment option in VWD (von willebrand disease)

Answer 29

VWF or DDAVP (stimulating endocrine cells to release VWF )

Question 30

what is a symptom of patients with VWD whose pathology is clearly stemming from both blood but also ENDOTHELIUM?

Answer 30

SEVERE INTRACTABLE (unstopable) bleeding from the gastrointestinal tract

due to vascular malformations in the gut blood vessels

Question 31

what treatment is not sufficient to control the bleedin in GI tract in VWD

Answer 31

VWF replacement

Question 32

what is a more recently discovered role of VWF? (also mention the classic role if u dont know well)

Answer 32

in haemostasis vwf mediates platelet adhesion to subendothelium and platelet aggregation
vwf stabilises circulating coagulation factor 8

NEW: ANGIOGENESIS
vwf controls blood vessel formation and integrity partly by regulating growth factor signalling (VEGFR, ANG-2)

Question 33

what pathogenic processes lead to activation of edothelium?

what risk facotrs are linked to these processes?

what does activation of the epithelium lead to?

Answer 33

inflammation
thrombosis
angiofenesis

high bp, mechanical stress
oxLDL, high glucose,
smoking, viruses,

atheorsclerosis ( in larger arteries)

Question 34

what is a very important factor that increases endothelial permeability to lipoproteins?

Answer 34

nitric oxide

Question 35

what are the 4 main mechanisms of pathology of the endothelium in atherosclerosis?

Answer 35

leukocyte recruitment
increase in permeability
decrease in sheer stress
angiogenesis

Question 36

when and where does leukocyte recruitment occur under NORMAL circumstances

Answer 36

in post capillary venules during inflammation

Question 37

what is the difference in structure of capillary vs post -capillary venule?

Answer 37

post cap ven simiral to cap but more pericytes

Question 38

describe the process of leukocyte adhesion - migraiton across an endothelial surface

Answer 38

1) rolling
2) slow rolling
3) arrest (pause)
now activated
4) adhesion, strengthening, spreading
5) intravascular crawling (little part of cell sfinonei namesa apo kapio junction horis na diapernaei ALI PLEVRA AKOMA)
6) paracellular and trancellular transmission