Vascular Endothelium Flashcards
3 layers of blood vessels
Which are the exceptions
Tunica intima
Tunica media
Tunica adventitia
capillaries and venules
What does tunica intima consist of?
Lamina propria(smooth muscle and connective tissue) Internal elastic membrane It is the endothelium of blood vessles
What does tunica media consist of?
External elastic membrane
Smooth muscle
What does tunica adventitia consist of?
Nerve
Vasa vasorum
What is the function of the vascular endothelium?
It separates blood from other tissues
How thick is the vascular endothelium and what is it formed by?
One cell deep, formed by a monolayer of endothelial cells
Life span and proliferation rate of endothelial cells + which is the exception in the proliferation rate
Long life
Low proliferation rate
Angiogenesis –> increase in proliferation rate
What is the function of endothelial cells? (4)
They regulate functions of blood vessles: Angiogenesis Thrombosis + haemostasis Inflammation Vascular tone and permeability
List endothelial dysfunctions in atherosclerosis (5)
- Leukocyte recruitment
- Permeability
- Blood flow
- Angiogenesis
- Senescence
Where do leukocytes adhere in inflammation?
To the endothelium of post-capillary venules and transmigrate into tissues
Where do leukocytes adhere in atherosclerosis?
To activated endothelium of large arteries and get stuck in the subendothelial space
Where do leukocytes gt stuck in the sub-endothelial space and why?
Between basement membrane and tunica media because they can’t chew through tunica media
Structure of capillaries
Endothelial cells surrounded by basement membrane and pericapillary cells (perycites)
Structure of post-capillary venule
Similar to capillaries but more pericytes
Strucure of an artery
3 thick layers (tunica adventitia, media, intima) rich in cells and extracellular matrix
Result of increased permeability of endothelium?
Leakage of plasma proteins through the junctions into the subendothelial space
Characteristics of laminar flow? (2)
- Streamlined
2. Outermost layer moving slowest and center moving fastest
Characteristics of distributed flow? (3)
- Interrupted
- Rate of flow exceeds critical velocity
- Fluid passes a constricton, sharp turn, rough surface
Where does atherosclerosis mostly occur?
At branchpoints where there is disturbed flow
Advantages of laminar flow (4)
Promotes:
- anti-thrombotic, anti-inflammatory factors
- endothelial survival
- NO production
- Inhibition of smooth muscle cell (SMC) proliferation
Disadvantages of disturbed flow (3)
Promotes:
- Coagulation,leukocyte adhesion
- Endothelial apoptosis
- loss of NO production
- SMC proliferation
Effects of NO on endothelium (6)
- Dilation of blood vessels
- Reduces oxidation of LDL
- Reduces release of superoxide radicals
- Reduces proliferation of SMC in the vessel wall
- Inhibits monocyte adhesion
- Reduces platelet activation
Define epigenetics
functionally relevant inheritable changes to the genome that do not involve a change in the nucleotide sequence, wich affect gene expression
List 3 key epigenetic mechanisms
DNA methylation
Histones modification
miRNA
