Pulmonary veins carry oxygenated blood from the lungs to the left atrium of the heart, while systemic veins return deoxygenated blood from the rest of the body to the right atrium of the heart. Superficial veins are located close to the surface of the skin and are not found near corresponding arteries. Deep veins are located deep within muscle tissue and are typically located near a corresponding artery with the same name. For example, coronary arteries and veins are deep veins located near the heart.
A vein can range in size from 1 mm up to 15 mm in diameter. The smallest veins in the body are called venules. They receive blood from the arteries via the arterioles and capillaries. The venules branch into larger veins which eventually carry the blood to the largest veins in the body, the vena cava. The blood is then transported from the superior vena cava and inferior vena cava to the right atrium of the heart.
The vein wall consists of three layers. The Tunica Adventitia is the strong out covering, made of connective tissue, collagen and elastic fibers. The Tunica Media is the middle layer, which is composed of smooth muscle and elastic fibers. The Tunica Intima is the inner layer consisting of an elastic membrane lining and endothelium tissue that is covered by elastic tissue.
The images below of veins were captured using the Fein Optic RB30 biological lab microscope and the HDCAM4 HD microscopy camera.
|Vein under the RB30 microscope at 40x.|
|Vein under the RB30 microscope at 100x.|
|Vein under the RB30 microscope at 400x.|