vascular epithelium Flashcards
what are the three layers of cells lining vessels other than capillaries?
tunica adventitia (think adventures= outdours- extenrla layer) = nerves
tunica media: smooth muscle cells
tunica intima: endothelium
how small are caps compared to hair
1/ of hair in width
what is the structure of capillaries
mainly endothelium supported by mural cells (pericytes) and a basement membrane
what happens in capillaries
exchange of oxygen and nutrients with tissues
How well spread/ distributed are capillaries?
almost every cell in body is in contact with microvascular endothelial cells
in what vessel type do the majority of the endothelial cells reside?
98% in microvasculature
how do the endothelial cells know that they are supposed to form monolayers and not stack onto eachother?
due to a phenomenon called contact inhibition, when they meet eachother at junctions signals are released that stop them from proliferating further
what is the proliferation rate of endothelial cells? (not in number just word) when is an exception?
dont proliferate much in vivo, only when angiogenesis
what are some of the fucntions of blood vessels that endothelium controls?
permeability
angiogenesis
haemostasis and thrombosis
INFLAMMATION
VASCULAR TONE (ud think this is only muscles buttt actuallyyy its not!)
how do endothelial cells control all thesevascular functions?
by cytokines and factors see slide 11
in what aspects do endothelial cells differ in different organs?
structure
function
molecular differences
how is it possible for endothelial cells to be organotypic (differ amongst organs)
although same dna as all cells, different expression profiles: meaning different rnas
how is the genetic profile of different endothelial types unalysed studied and presented?
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
what is the human cell atlas
1) international collaborative consortium
2) charts cel types in the healthy body
3) from development to adulthood
how do endothelial cells become tissue specific
tissue specific MICROENVIRONMENT influences phenotype of endothelial cells
tissue specific endothelial cells produce different angiocrine factors which are ESSENTIAL for
tissue homeostasis and regeneration
what is the most abundant cell type in the heart?
endothelial cell
(Then its cardiomyocytes and then stromal cells)
what two cell type sin the heart communicate and what is the term used to describe this communication?
cardiomyocytes and endothelial cells crosstalk!
what is the most common type of angiogenesis in adults (meaning not part of development) called?
sprouting angiogenesis
define angiogenesis
formation of neo-vessels FROM PRE-EXISTING blood vessels
describe the cascade of events in angiogenesis
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
what role do transcription factors play in angiogenesis?
regulate the precise temporal and spatial co-ordination of the expression of multiple genes during angiogenesis
what are some physiological processes that involve angiogenesis
1) development
2) menstrual cycle
3) wound healing
what are 2 crucial pathologies that involve angiogenesis?
cancer
atherosclerosis
what is the angiogenic switch in cancer?
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.
