case 2 - endothelium in heart and disease Flashcards
What are the three layers of the artery and vein?
The three layers are Tunica intima, Tunica media, and Tunica externa/tunica adventitia.
What is the Tunica intima made up of?
The Tunica intima is made up of endothelium.
What is the Tunica media made up of?
The Tunica media is made up of smooth muscle and elastic fibre.
What is the endothelium monolayer?
Single cell thick; Innermost layer of blood vessels
function of the internal elastic lamina?
Separates endothelium from tunica media (smooth muscle aspect of the tunica media)
What is the function of the external elastic lamina?
Separates tunica media from tunica adventitia
What is the tunica adventitia?
Most complex layer (of blood vessels): Contains fibroblasts, immunomodulatory cells (dendritic and macrophages), progenitor cells, vasa vasorum endothelial cells and pericytes, and adrenergic nerves
what do continuous capillaries contain?
basement membrane
endothelial layer (tunica intima)
intercellular cleft
what do fenestrated capillaries contain?
fenestrations
what do sinusoid capillaries contain?
incomplete basement membrane
intercellular gap
what does the semipermeable capillary border of the blood brain barrier allow and block?
The semipermeable capillary border allows selective passage of blood constituents into the brain and blocks the passage of polar molecules, macromolecules and pathogens
what do endothelial cells line?
Endothelial cells line:
All veins and arteries
Lymphatic vessels
All four chambers of the heart
Heart valves
Capillaries
what is in a healthy human artery?
Blood vessel is open - no obstruction
Smooth muscle are contractile in phenotype
Endothelial cells aligned in one
direction - No damage to endothelial cells
what does “Contractile in phenotype” mean?
this basically means that smooth muscle cells have the ability to contract (shorten) and then return to their original length, which is often described as the muscle “springing back.”
What is a characteristic of smooth muscle cells in atherosclerosis?
Smooth muscle cells have a synthetic and proliferative phenotype.
What causes foam cell formation in atherosclerosis?
Foam cell formation is caused by the infiltration of immune cells, such as macrophages
What type of damage is associated with atherosclerosis?
Endothelial damage - disruption to orientation and flow of endothelial cells.
what does increased endothelial dysfunction lead to?
Increased endothelial dysfunction leads to vascular dysfunction
key roles of the endothelium are:
Inhibition of platelet activation and affecting clotting
Inflammatory cascade - marginalisation, rolling, adhesion and transmigration of immune cells
Cardiac contraction
Vascular tone - how dilated or constricted vessels are
Angiogenesis – formation of new vasculature
name extrinsic neural factors in the control of vascular tone
Neuropeptide Y increases vascular tone
Acetylcholine decreases vascular tone
name extrinsic humoral factors in the control of vascular tone
Vasopressin increases vascular tone
Atrial natriuretic peptide decreases vascular tone
name intrinsic myogenic factor in the control of vascular tone
vascular tone set by muscle
name intrinsic humoral factors (these are local - only affect the immediate/nearby area where they’re released) in the control of vascular tone
Histamine increases vascular tone
Bradykinin decreases vascular tone
name intrinsic endothelium factors in the control of vascular tone
Endothelin increases vascular tone
Nitric oxide decreases vascular tone
