Histology of Blood Vessels
three layers of most blood vessels
- tunica intima
- simple, squamous epithelium (endothelium)
- basal lamina
- loose connective tissue
- includes internal elastic membrane
- tunica media
- circumferentially arranged layers of smooth muscle cell
- in arteries surrounded by external elastic lamina
- tunica adventitia
- longitudinally arranged collagenous tissue
Capillaries
- continuous
- muscle, lung, CNS
- pinocytotic vesicles involved in transport processes
- pericytes may be found in association with capillary
- fenestrated
- endocrine glands and sites of fluid and metabolite absorption
- fenestrations of 80-100 nm diameter
- fenestrations may have nonmembranous diaphragm across opening
- discontinuous (sinusoids)
- liver, spleen and bone marrow
- specialised cells among endothelial cells (e.g. Kuppfer and Ito cells
in liver)
- unique shape of endothelial cells
- presence of unusually wide gaps between endothelial cells
- partial or total absence of basal lamina
Arteriovenous Shunts
- allow blood to bypass capillary beds
- contraction of precapillary sphincters shunt blood straight through to
venules
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8.5.3 Histology of Blood Vessels & Tissues [Hist]
[Currently: 1 lecture + 1 ´ 2h class]
| Structure and functions of the walls of arteries,
arterioles, capillaries, venules and veins. |
|
| Endothelium, tunica intima, tunica media, tunica
adventitia; elastic and non-elastic vessels. |
Atherosclerosis. |
| Structure and function of capillaries. Continuity of
endothelium (and endocardium) throughout the vascular system. Fenestrated
and non-fenestrated capillaries; sinusoids; syncytiotrophoblast. Diversity
of capillary permeabilities in different organs. |
Production of vasoactive substances by endothelium |
| Blood vascular patterns in organs, esp. kidney, liver,
skin. |
|
| The portal systems of the liver, kidney, and pituitary
gland. |
|
| Arterio-venous anastomoses. |
Structural changes in blood vessels in hypertension |
|