Vascular Endothelium Flashcards
What are the 3 layers of blood vessels (from outermost to innermost)?
- tunica adventitia
- tunica media
- tunica intima
What makes up the tunica adventitia?
- vasa vasorum
- nerves
What makes up the tunica media?
- external elastic membrane
- smooth muscle
What makes up the tunica intima?
- internal elastic membrane
- lamina propria
- endothelium
What is the lamina propria?
- smooth muscle
- connective tissue
What are capillaries and venules comprised of?
- endothelium
- pericytes (mural cells)
- basement membrane
What happens at capillaries?
exchange of nutrients and oxygen between blood and tissues
What does the microvascular endothelium do?
- source of angiocrine factors
- promote tissue homeostasis and organ regeneration
What is the impact of a dysfunctional endothelium?
- contributes to disease
- ischemia
- chronic inflammatory diseases
- cancer
- diabetes
- atherosclerosis
Do endothelium cells vary?
- yes, they have organotypic properties and expression profiles
- have structural, functional and molecular differences
What are the properties of endothelial cells in the muscle, lung, skin and blood brain barrier?
continuous non-fenestrated
What are the properties of endothelial cells in the kidney glomerulus, GI tract?
continuous fenestrated
What are the properties of endothelial cells in the liver and marrow?
discontinuous
What are the properties of endothelial cells?
- very flat
- about 1-2 micrometers thick
- about 10-20 micrometers in diameter
What is contact inhibition?
when the junctions of 2 cells join and establishes a junction causing the cells to stop growing
What is the lifespan of endothelial cells?
- long
- low proliferation rate
(unless angiogenesis is necessary)
What are the functions of endotheliun?
- vascular tone
- permeability
- angiogenesis
- haemostasis and thrombosis
- inflammation
What happens when the endothelium is at rest?
promotion of:
- anti-inflammatory
- anti-thrombotic
- anti-proliferative
What happens when the endothelium is activated?
promotion of:
- pro-inflammatory
- pro-thrombotic
- pro-angiogenic
What activates the endothelium?
- smoking
- viruses
- mechanical stress
- inflammation
- high BP
- OxLDL
- high glucose
What happens when there is long term/chronic activation of the endothelium?
- thrombosis
- senescence
- permeability
- leukocyte recruitment
all cause: atherosclerosis
What are the characteristics of endothelial dysfunction in atherosclerosis?
- endothelial permeability
- leukocyte migration
- endothelial adhesion
- leukocyte adhesion
What happens in the fatty-streak formation in atherosclerosis?
- smooth muscle migration
- foam cell formation
- t cell activation
- adherence and aggregation of platelets
- adherence and entry of leukocytes
What happens in the formation of an advanced, complicated lesion of atherosclerosis?
- macrophage accumulation
- formation of a necrotic core
- angiogenesis
- fibrous cap formation
What are the triggers of endothelial dysfunction in atherogenesis?
- oxidative stress
- pro-inflammatory cytokines
- infectious agents
- environmental toxins
- haemodynamic forces