Histology of CV System Flashcards
large arteries
elastin in walls
distend(expand) during systole
recoil(narrow) during diastole
3 layers of large arteries
tunica adventitia- collagen and elastic fibres, vaso vasorum carried away waste
tunica media- smooth muscles and less collagen and elastic fibres
tunica intima- endothelium, basal lamina, subendothelial layer
Muscular arteries
more smooth muscle
less elastin
tunica intima thickens with age
small arteries and arterioles
small arteries have higher number of smooth muscle layers than arterioles
arterioles control flow of blood to capillaries- constrict to increase resistance
arterioles will dilate during exercise to provide more blood
capillaries
single endothelial layer and basal lamina(only tunica media)
have specialised cells called pericytes to help regulate blood flow
forms blood vascualr network to allow exchange of materials between body organs and bloodstream
3 types of capillary
continuous capillary- have continuous vascular endothelium and basal lamina
Fenestrated capillary- have opening in only in endothelial layer called fenstruations
discontinuous capillary - have large gaps in both endothelial and basal lamina
where to find 3 types of capillary
continuous - connective tissue, muscle, skin
fenstruated - endocrine organs, gall bladder, kidneys
discontinous - liver, spleen, bone marrow
venules and small veins
collect blood from capillaries and join together to form veins
venule tunica media has 1-2 layers of smooth muscle, samll vein’s have 3-4
2 types of venules
postcapillary venules- pericytes, endothelium/basal layer
muscular venules- smooth muscle and thin tunica adventitia
medium veins
continuation of small veins
valves- to stop backflow
more smooth muscle
found in deep veins such as radial
large veins
continuation of medium veins
tunica layers are less distinct than medium
tunica adventita has smooth longitudinal muscle
3 layers of heart wall
epicardium
myocardium
endocardium
heart valves
3 layers- fibrosa, spongiosa, ventriularis layers
valves exposed to blood and allow nutrients and oxygen to diffuse into interstatial cells that provide homeostatic value
aneurysm
damaged (often large) vessel over time becomes weak and englarges and forms bulging defect called aneurysm
may rupture to cause internal bleeding and be fatal
Atherosclerosis
build up of plaque in medium-large arteries
if in conorary artery can cause conorary heart disease
if in abdominal aorta or renal artey can cause hypertension secondary to stenosis of renal artey
