11) Histology of circulatory system (MEQ)

Question 1

What are the 3 layers in blood vessels

Answer 1

tunica intima
tunica media
tunica adventitia

Question 2

(MCQ) What is present in tunica intima

Answer 2

Endothelium
Subendothelial layer
Internal elastic lamina

Question 3

function of vasa vasorum

Answer 3

Provide metabolites to the tunica adventitia and the tunica media

Question 4

Why vasa vasorum are more frequent in veins than in arteries?

Answer 4

because veins generally have thinner walls and may rely more on these vessels for oxygenated blood supply to meet their metabolic needs.

Question 5

Histology feature of muscular artery (medium size artery)

Answer 5

**Tunica intima **- endothelium subendothelial layer(narrow) and internal elastic lamina

Internal elastic lamina - very sharply defined. It is seen as a single, thick, homogenous, highly refractile membrane.

Tunica media - smooth muscle arranged circularly, few collagen and elastic fibers

Tunica adventitia - Present external elastic lamina

Question 6

Histology feature of Elastic Artery (Large Artery)

Answer 6

Tunica intima - endothelium, subendothelial layer(thick) and internal elastic lamina

Internal elastic lamina - not distinct

Tunica media - thick with many elastic fibers and some smooth muscle

Tunica adventitia - Has vasa vasorum and relatively thin or no external elastic lamina

Question 7

Histology feature of Vein

Answer 7

Thin walls with large lumens
Appear flattened (collapsed)

Tunica Intima:
Thin
Endothelium appears smooth & lies on subendothelial layer
IEL mostly absent
Prominent valves

Tunica Media:
Thin
Smooth muscle cells reduced /absent
Collagenous fibers arranged circulary (predominate)

Tunica Adventitia:
Thickest layer
Longitudinally arranged discrete bundles of smooth muscle
EEL absent
Vasa vasorum present up to tunica intima