Histology of the heart and blood vessels Flashcards
What are the 3 layers of the blood vessels?
Tunica intima
Tunica media
Tunica adventitia
What makes up the tunica intima?
Squamous epithelium termed the endothelium which is supported by the basal lamina (Connective tissue)
What makes up the tunica media?
Smooth muscle and some elastic fibres
What makes up the tunica adventitia?
Supporting connective tissue
What is found between the tunica intima and tunica media?
The internal elastic membrane
What is found between the tunica media and tunica adventitia?
The external elastic membrane
Which vessels contain smooth muscle in their tunica adventitia?
Veins
Which vessels have the thickest tunica media?
Arteries
Which vessels have the thickest tunica adventitia?
Veins
What are vasa vasorum?
Blood vessels that branch from the main artery and move into the tunica adventitia in order to supply the outer most layers of the blood vessels with oxygen and nutrients
How many layers of smooth muscle is found in the tunica media of an arteriole?
1 to 2 layers
What are the characteristics of a meta-arteriole?
In meta-arterioles, the smooth muscle is replaced by discontinuous, non contractile cells called pericytes
What forms the walls of a capillary?
Endothelial cells and a basal lamina only, with pericytes at intervals
What are the 3 types of capillary?
Continuous
Fenestrated
Discontinuous/sinusoidal
Where are continuous capillaries found?
Connective tissue, muscle, lungs, skin and nerves