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Fenestrated capillaries have diaphragms that cover the pores whereas sinusoids lack a diaphragm and just have an open pore. These types of blood vessels allow red and white blood cells (7.5 μm – 25 μm diameter) and various serum proteins to pass, aided by a discontinuous basal lamina.
The tunica intima (Neo-Latin "inner coat"), or intima for short, is the innermost tunica (layer) of an artery or vein. It is made up of one layer of endothelial cells (and macrophages in areas of disturbed blood flow), [1] [2] and is supported by an internal elastic lamina. The endothelial cells are in direct contact with the blood flow.
Surface charges on vessel walls affect the flow of ions through the capillaries and fluid mechanics in microvasculature. A charged endothelial lining creates a bound layer of ions where diffusion occurs between the cell walls and lumen, also known as the stern layer. This creates a diffuse layer, a charge gradient where ions move towards the ...
The choriocapillaris forms a single layer of anastomosing, fenestrated capillaries having wide lumina with most of the fenestrations facing toward the retina. The lumen is approximately three to four times that of ordinary capillaries, such that two or three red blood cells can pass through the capillary abreast, whereas in ordinary capillaries ...
The endothelium is a thin layer of single flat cells that line the interior surface of blood vessels and lymphatic vessels. [1] Endothelium is of mesodermal origin. Both blood and lymphatic capillaries are composed of a single layer of endothelial cells called a monolayer. In straight sections of a blood vessel, vascular endothelial cells ...
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 entirely made of connective tissue.
The choroid, also known as the choroidea or choroid coat, is a part of the uvea, the vascular layer of the eye. It contains connective tissues , and lies between the retina and the sclera . The human choroid is thickest at the far extreme rear of the eye (at 0.2 mm), while in the outlying areas it narrows to 0.1 mm. [ 1 ] The choroid provides ...
In the largest vessels, the vasa vasorum penetrates the outer (tunica adventitia) layer and middle (tunica media) layer almost to the inner (tunica intima) layer. In smaller vessels it penetrates only the outer layer. In the smallest vessels, the vessels' own circulation nourishes the walls directly and they have no vasa vasorum at all.