Circulatory System Histology Flashcards
Layers of blood vessels
Tunica intima
Tunica media
Tunica adventitia
Tunica intima
Single innermost layer of squamous epithelial cells (endothelial cells) supported by basal lamina and thin layer of connective tissue
Tunica media
predominately made up of smooth muscle. it’s thickness varies
Tunica adventitia
Made up of supportive connective tissue
What separates tunica intima and media?
Internal elastic membrane
What separates tunica media and adventitia?
External elastic membrane
Why are the largest arteries called elastic arteries?
They have many sheets of elastic fibres in their tunica media to provide elastic recoil
Arterioles
One or two layers of smooth muscles in their tunica media and essentially no adventitia
Capillaries
Composed of endothelial cells and a basal lamina
Pericytes
Connective tissues cells that have contractile properties. Found at intervals just outside the basal lamina
Most common capillaries and where they are found
Muscle, connective tissue, lung, skin, nerve
Fenestrated capillaries
Have pores in wall
Found in mucosa of the gut, endocrine glands and glomeruli of kidney
Discontinuous/ sinusoidal capillaries
Have large gaps which macromolecules and some cells can pass though
The basal lamina is discontinuous or absent
Found in liver, spleen and bone marrow
Microvasculature
Small materials connect to a post capillary venue through a network made up of metarterioles throughfare channels and capillaries
What helps control flow through microvasculature network?
Precapillary sphincters
