Histology GS

Question 1

List the three major types of blood vessels

Answer 1

arteries capillaries veins

Question 2

Describe (with the aid of a diagram) the basic composition of the wall of a blood
vessel

Answer 2

the wall of a blood vessel is made of squamous endothelial cells

Question 3

Describe (with the aid of a diagram) the wall of an elastic/conducting artery

Answer 3

there are three layers to a blood vessel, the tunica intima, the tunica media and the tunica adventita. In elastic arteries the tunic intima is the thinnest out of the three layers, this is the internal elastic membrane which appears dark on the histology slides. the next layer is the tunica media which is composed of alternating layers of circumferentially arranged smooth muscle and the sheets of elastic tissue. This is the thickest layer in elastic arteries and the number of elastic lamelllae is linked to blood pressure in the artery. The next layer is the tunica adventitia whic i the outer most layer that is a layer of dense irregular connective tissue and this is less than half the thickness of the tunica media.

Question 4

Describe (with the aid of a diagram) the wall of a muscular/distributing artery

Answer 4

A prominent internal elastic lamina separates the tunica intima from the media. In larger arteries, an external elastic lamina also separates the tunica media from the adventitia.
The tunica media is composed of concentric layers of smooth muscle cells. The contraction and relaxation of these muscle cells regulate blood flow by changing the size of the lumen.

Question 5

Compare and contrast arterioles with venules

Answer 5

Arterioles regulate the flow of blood into capillary beds. They provide the majority of the resistance to blood flow in the body.
The tunic media is reduced to one or two concentric layers of smooth muscle cells.
The contraction of the smooth muscle cells constricts the lumen of the arteriole, reducing the flow of blood, and increasing vascular resistance

Question 6

Compare and contrast the walls of arteries and veins

Answer 6

have thinner walls than arteries with less distinct layers. The tunica adventitia is the thickest of the three layers.
Tunica Intima - inner layer composed of endothelium and a thin layer of collagen fibrils
Tunica Media - middle layer of only a few (3 to 8) layers of smooth muscle.
Tunica Adventitia - outer layer of dense irregular connective tissue containing mostly longitudinal or spiral arrangements of smooth muscle and collagen fibers.
Vasa Vasorum - blood vessels that supply the tunica adventitia and tunica media.