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Though veins might make it appear as such, human blood is never naturally blue. [3] The blue appearance of surface veins is caused mostly by the scattering of blue light away from the outside of venous tissue if the vein is at 0.5 mm deep or more. Veins and arteries appear similar when skin is removed and are seen directly. [4] [5]
Deep veins are deeper in the body and have corresponding arteries. Perforator veins drain from the superficial to the deep veins. [16] These are usually referred to in the lower limbs and feet. [17] Superficial veins include the very small spider veins of between 0.5 and 1 mm diameter, and reticular or feeder veins. [18] Venous plexuses
A venous lake (also known as phlebectasis [1]) is a generally solitary, soft, compressible, dark blue to violaceous, 0.2- to 1-cm papule commonly found on sun-exposed surfaces of the vermilion border of the lip, face and ears. [2] [3] [4] Lesions generally occur among the elderly. [5] [6]
Because blood pools in the veins after death, arteries look empty. Ancient anatomists assumed they were filled with air and that they were for the transport of air. The Greek physician, Herophilus, distinguished veins from arteries but thought that the pulse was a property of arteries themselves.
In anatomy, the venae cavae (/ ˈ v iː n i ˈ k eɪ v i /; [1] sg.: vena cava / ˈ v iː n ə ˈ k eɪ v ə /; from Latin 'hollow veins') [2] are two large veins (great vessels) that return deoxygenated blood from the body into the heart. In humans they are the superior vena cava and the inferior vena cava, and both empty into the right atrium ...
The great saphenous vein (GSV) or long saphenous vein (/ s ə ˈ f iː n ə s /) is a large, subcutaneous, superficial vein of the leg.It is the longest vein in the body, running along the length of the lower limb, returning blood from the foot, leg and thigh to the deep femoral vein at the femoral triangle.
Veins close to the surface of the skin appear blue for a variety of reasons. However, the factors that contribute to this alteration of color perception are related to the light-scattering properties of the skin and the processing of visual input by the visual cortex, rather than the actual color of the venous blood. [36]
Normal blood vessel (left) vs. vasodilation (right) Vasodilation, also known as vasorelaxation, is the widening of blood vessels. [1] It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. [2]