Lecture 16 Flashcards
(18 cards)
tunica intima
Inner most layer of vessel wall. Endothelium lining, basal lamina and thin CT
Tunica media
Middle layer of vessel wall, SM and elastic fibres
tunica adventitia
Outer layer, collagen, elastic fibres, fibroblasts, nerves sometimes SM
SM
Control dilation and constriction of vessels. Thicker in arteries than veins. Produces collagen, elastin and ECM
Elastic fibres
Allows vessels to return to OG shape after stretching.
collagen
provides strength
Shape of lumen
artery is more circular while vein is less regular/circular/more collapsed.
Lumen size
Artery has smaller lumen than vein due to thicker size
Wall thickness
Arteries has much thicker tunica media than vein
arterioles
30-200um diameter. Contribute to peripheral vascular resistance for BP regulation. Still have SM but only 1-2 layers that contract/relaxes under autonomic control. Thin tunica adventitia. Usually have neighbouring venuoles.
Veins vs arteries
veins have thinner walls, larger lumen, irregular shape, tunica adventitia is thickest layer and some have valves. Large veins likely to accompany elastic arteries. Medium veins likely to accompany muscular veins. Valves are extensions of tunica intima
Elastic arteries
Intima: Endothelium, CT
Media: Alternating layers of SM and elastic lamellae
Adventitia: collagen and elastic fibres, fibroblasts
Muscular arteries
Intima: Endothelium, internal elastic membrane, CT
Media: SM, collagen, some elastin
Adventitia: CT and/or external elastic membrane
Medium and small veins
Thinner tunica media than muscular artery. SM, collagen and elastin. Thicker tunica adventitia than tunica media. Composed of elastin
Venules
10-15um diameter. Endothelium sometimes CT and SM
Venous valves
continuation of tunica intima. consists of endothelial lined cells and a bit of CT. Prevents blood pooling in legs esp. in legs
Varicose veins
valves dont work effectively. Extensive period s of standing increases pressure, genetic factors
