1. Wall of all arteries is composed of 3 tunics:

1. tunica interna (or intima);
2. tunica media;
3. tunica externa (or adventitia). It is composed of  loose irregular connective tissue.

 

2. Tunica intima of all arteries is composed of 3 layers:

1. endothelium (simple squamous epithelium);
2. subendothelial layer (loose irregular connective tissue);
3. internal elastic lamina (or membrane).

3. Histologically arteries are classified on 2 types:

 

1. muscular arteries;
2. elastic arteries.

 

1. If in tunica media amount of smooth muscle cells more, than amount elastic fibres, it is muscular artery (for example, a. femorale).

 

2. If tunica media contains 40-60  fenestrated elastic membranes and less smooth muscle cells, it is elastic artery (for example, aorta, pulmonary artery)

 

3. External elastic membrane separates tunica media and tunica adventitia.

 

1. Veins histologically are classified on 2 types:
   1. muscular veins;
   2. fibrous veins ( or nonmuscular veins).
2. If wall is composed 3 tunics, and tunica media contains smooth muscle cells, it is muscular vein (for example, v. femorale).
3. Wall of muscular veins, like wall of arteries, is composed of 3 same tunics:
   1. tunica interna (or intima);
   2. tunica media;
   3. tunica externa (or adventitia). It is composed of loose irregular connective tissue.
4. Tunica intima of muscular veins contains only 2 layers (in arteries – 3 layers)

 

1. endothelium (simple squamous epithelium);
2. subendothelial layer (loose irregular connective tissue);

 
Internal and external elastic membranes in wall of muscular veins are ABSCENT.
 

5. If vein wall does not contain smooth muscle cells, it is nonmuscular vein.

Its wall does not have 3 typical tunics and contains only 2 layers:

1. endothelium ( simple squamous epithelium) ;
2. thick layer of loose irregular connective tissue, which attached to organ stroma.
6. Fibrous (or nonmuscular) veins locate in retina, compact bone, spleen, placenta. 
Куратор темы – доцент В.В. Бондаренко.