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A rete mirabile (Latin for "wonderful net"; pl.: retia mirabilia) is a complex of arteries and veins lying very close to each other, found in some vertebrates, mainly warm-blooded ones. The rete mirabile utilizes countercurrent blood flow within the net (blood flowing in opposite directions) to act as a countercurrent exchanger.
The tunica media may (especially in arteries) be rich in vascular smooth muscle, which controls the caliber of the vessel. Veins do not have the external elastic lamina, but only an internal one. The tunica media is thicker in the arteries rather than the veins. The outer layer is the tunica adventitia and the thickest layer in veins. It is ...
The peripheral vascular system is the part of the circulatory system that consists of the veins and arteries not in the chest or abdomen (i.e. in the arms, hands, legs and feet). [1] [2] The peripheral arteries supply oxygenated blood to the body, and the peripheral veins lead deoxygenated blood from the capillaries in the extremities back to ...
There are three sizes of veins: large, medium, and small. Smaller veins are called venules, and the smallest the post-capillary venules are microscopic that make up the veins of the microcirculation. [2] Veins are often closer to the skin than arteries. Veins have less smooth muscle and connective tissue and wider internal diameters than ...
Arteries have the highest pressure and have narrow lumen diameter. [clarification needed] Systemic arteries are the arteries (including the peripheral arteries), of the systemic circulation, which is the part of the cardiovascular system that carries oxygenated blood away from the heart, to the body, and returns deoxygenated blood back to the ...
The common carotid artery is contained in a sheath known as the carotid sheath, which is derived from the deep cervical fascia and encloses also the internal jugular vein and vagus nerve, the vein lying lateral to the artery, and the nerve between the artery and vein, on a plane posterior to both. On opening the sheath, each of these three ...
Vasa vasorum are more frequent in veins than arteries. [2] Some authorities hypothesize that the vasa vasorum would be more abundant in large veins, as partial oxygen pressure and osmotic pressure is lower in veins. This would lead to more vasa vasorum needed to supply the vessels sufficiently.
Veins have a much higher compliance than arteries (largely due to their thinner walls.) Veins which are abnormally compliant can be associated with edema . Pressure stockings are sometimes used to externally reduce compliance, and thus keep blood from pooling in the legs.