The capillary is the opening of a blood vessel, which collects fluid, secretes it, and returns the fluid to the circulatory system.
The capillary walls are very fine, about 8 to 10 millimeters (a millimeter is about 0.1 mm), large enough for red blood cells to flow easily through them in a single column. The outer layer of the cells forming the walls is known as the basement membrane of the smaller vessels and is made up of several layers of collagen and elastic fibers. The walls of the capillary have the most permeability of any tissue in the body, and therefore the blood passes through it faster than with any other structure in the body.
Blood flows through the capillary wall as it is carried to various organs such as the heart, lungs, liver, and brain. It also carries nutrients and wastes from one organ to another. As the liquid blood moves, it leaves behind a thin film of semi-solidified material called the fibrin. This semi-solidified material coats the inside of the blood vessels, helping in blood clotting and keeping them closed and flowing smoothly.
The fibrin is what gives blood its characteristic “thick” appearance.
The thickness of the fibrin depends on how long the blood vessels have been in use. If the fibrin has not been in use for a long time, it becomes thinner over time. In addition, the process of platelet creation is much slower in a healthy body than it is in an unhealthy one. This is because the bone marrow produces fewer platelets, so it takes time to create new ones. As we grow older, this process slows down further, resulting in a thickening of the blood vessels, as well as a lowering of our ability to produce and absorb vitamin D.
As we get older, the walls of our capillary walls become less permeable and therefore less easily able to carry liquid blood. As a result, the blood that enters them is much less concentrated, causing them to retain less water than they would if they were permeable more or less constantly.
This decreased blood circulation can occur for a variety of reasons. One of these reasons is due to a decrease in the efficiency of the capillary walls, as the body ages.
A decrease in the capillary walls makes it harder for the body to produce collagen and elastin, the two primary proteins needed to make new cells.
Another reason is due to the aging process itself. As the body ages, more fat cells accumulate in the walls of the capillary. Because they can not hold as much fluid, the cells begin to separate. This separation causes a greater loss of water in the walls of the capillary, as well as a decrease in the quality of the collagen and elastin that are being produced.
In addition, as we age, the flow of the blood is not as constant, because the veins of the capillary are less permeable and therefore there are more loss of fluid and therefore less effective removal of the fluids. This reduces the effectiveness of the blood to the area of the capillary walls, decreasing the effectiveness of the capillary walls.
There are some benefits to the aging process, however. The decreased permeability of the capillary walls, which reduce the permeability of the blood, make it harder for the blood to travel through the tissues in the area and decrease the amount of fluid that is pumped through the capillary. This allows the body to use less fluid, thus decreasing the amount of fluid that is lost in the capillary walls.