Search results
Results From The WOW.Com Content Network
Individual capillaries are part of the capillary bed, an interweaving network of capillaries supplying tissues and organs. The more metabolically active a tissue is, the more capillaries are required to supply nutrients and carry away products of metabolism.
The structure of the vasa vasorum varies with the size, function and location of the vessels. Cells need to be within a few cell-widths of a capillary to stay alive. 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 vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. [1] [2] It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels (from Greek kardia meaning heart, and Latin vascula meaning vessels).
A key role in this concerted action, which leads to a 2-to-20 fold increase in vascular diameter, depending on species size (mouse versus human), are the transcription factors AP-1, egr-1, carp, ets, by the Rho pathway and by the mitogen activated kinases ERK-1 and -2. In spite of the enormous increase in tissue mass (up to 50-fold), the degree ...
Capillary walls contain of a monolayer of endothelial cells. There are two ways for molecules to diffuse through the endothelial monolayer: through gaps between the cells or directly through the cells. Molecules diffuse through the capillary walls due to concentration gradients. Diffusion between the cells changes depending upon the type of ...
The venous system apart from the post-capillary venules is a high volume, low pressure system. Vascular smooth muscle cells control the size of the vein lumens, and thereby help to regulate blood pressure. [31] The post-capillary venules are exchange vessels whose ultra-thin walls allow the ready diffusion of molecules from the capillaries. [10]
General diagram of a portal venous system, for example, this occurs in the hypophyseal portal system between the hypothalamus and the anterior pituitary gland.. In the circulatory system of vertebrates, a portal venous system occurs when a capillary bed pools into another capillary bed through veins, without first going through the heart.
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 ...