Histology of the Heart and Blood Vessels

The endocardiumMyocardia, and epicardium

Inner lining of the heart chambers: tunica intimate equivalent in the blood vessels

Heart muscle: tunica media equivalent

Simple squamous epithelium over CT: contains autonomic nerves: tunica adventitia equivalent

The pulmonary artery is the only artery that carries deoxygenated blood, and the pulmonary vein is the only vein that carries oxygenated blood

Endothelium, tunica intima, tunica media, external elastic lamina, and tunica adventitia

Almost all blood vessels in the body are lined with simple squamous epithelium. However, the one exception is the blood vessels in the lymph nodes, which are lined by cuboidal cells.

Tunica intima has an inner and an outer wall. The inner wall is the endothelium and the outer wall is the internal elastic membrane. The outer wall contains arteries, veins. The internal elastic membrane is more promenent in arteries.

This is the middle layer, and it consists of smooth muscle arranged in a circular fashion. This is the thickest layer in the arteries, thin in the veins. non-existent in capillaries. It contains type III collagen and elastic fibers.

This is a thin sheet of elastin that lies between the tunica media and adventitia

This is an outer layer consisting of loose connective tissue that wraps the vessels and fuses with surrounding CT that lies between the blood vessels. It contains the vaso vasorum

This is a network of blood vessels in the adventitia that supply the outer vessel layers. These vessels are usually the first ones affected by diabetes.

These are a single layer of endothelium (simple squamous). They have no tunica media, and a thin tunica adventitia that connects to neighboring connective tissue.

1. Non-fenestrated2. Fenestrated3. Discontinuous capillaries

Non-fenestrated capillaries have endothelial cells that line the capillary and form zonula occludens junctions. The most common type of capillary: found in the iris and retina