Histology of Blood Vessels and Blood Cells

Question 1

Describe the Tunica Intima.

Answer 1

Comprised of endothelial cells which are simple squamous epithelial cells named after their embryonic origin.

Question 2

Describe the Tunica Media.

Answer 2

Arteries have a circular arrangement of smooth muscle within this layer. Thickness varies.

As the system runs from arteries to arterioles, the smooth muscle of the tunica media decreases.

Exception is elastic arteries where the smooth muscle of the tunic media is replaced with elastic fibres. This is to tightly control the pressure of blood exerted against the vessel much more than smooth muscle. Provides elastic recoil.

Question 3

Describe the Tunica Adventitia.

Answer 3

Made from a supporting connective tissue.

Consists of collagen fibres and blends with the surrounding connective tissue.

Question 4

Describe the Internal Elastic Membrane.

Answer 4

The tunica intima and the tunic media are separated by an elastic tissue known as the internal elastic membrane. This is not a continuous layer as it contains perforations within the layer.

Question 5

Describe the External Elastic Membrane.

Answer 5

The tunic media and the tunica adventitia are separated by an elastic tissue known as the external elastic membrane. This is not a continuous layer as it contains perforations.

Question 6

What are capillaries composed of?

Answer 6

Capillaries are composed of a layer of simple squamous epithelial cells (endothelium), connective tissue and a basal lamina.

Question 7

What are the 3 types of capillaries?

Answer 7

Continuous, fenestrated and discontinuous.

Question 8

Name the granulocytes of white blood cells.

Answer 8

Neutrophils, Eosinophils and Basophils.

Question 9

Name the agranulocytes of white blood cells.

Answer 9

Monocytes and Lymphocytes.