Capillaries

Information to promote strong capillaries (blood vessels) and capillary walls.

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  1. What are Capillaries?
  2. What are the Functions of Capillaries?
  3. Help for Capillaries

What are Capillaries?

Capillaries are tiny blood vessels, (about 10 micrometers in diameter) that form part of the circulatory system. These tiny structures are located within the tissues of the body and transfer blood from the arteries, through the tissues and back to the veins.

Capillary blood vessel's walls are thin and narrow and the red blood cells can only travel through them in single file. Substances such as oxygen, carbon dioxide, nutrients and wastes are passed through the walls of the capillaries. This makes the capillaries the main area of exchange between the fluid (called lymph) bathing the body tissues and the blood.

Because they are so numerous and their diameter is so small, Capillary blood vessel's purpose is to provide a large surface area in order to maximize diffusion of oxygen and nutrients.

The Different Types of Capillaries

There are three different types of capillaries that perform specific functions for the body -continuous capillaries, fenestrated capillaries, and sinusoidal capillaries. Each type of capillary is structured differently and this controls the degree to which diffusion occurs.

Continuous capillaries have the thickest endothelial wall and only allow water and ions into their pathways. Fenestrated capillaries have "windows" that allow larger molecules in and out of the capillaries. Sinusoidal capillaries have the greatest amount of permeability, letting red blood cells and proteins in through the endothelial walls.

What are the Functions of Capillaries?

The primary function of capillaries is to allow the exchange of materials between the blood and tissue cells. Because the capillaries are so small, these substances pass right through them in a process called diffusion.

Capillaries also supply blood to the organs. Strong capillaries perform the vital function of feeding the organ with amino acids, proteins and oxygen – if the organ cells do not receive oxygen, they will die. They also allow for waste products to be received from the organs. They then perform the very important function of transporting waste out of the body.

Tissues such as skeletal muscle, liver, and kidney have extensive capillary networks because they are extremely metabolically active and need an abundant supply of oxygen and nutrients. Other tissues, such as connective tissue, have a less abundant supply of capillaries.

Help for Capillaries

Strong capillaries are vital to the circulatory system, as they are the ultimate delivery network for nutrients and waste between the organs and the bloodstream. However, a poor diet, smoking, alcohol and all kinds of other environmental factors and pollutants can work to decrease the effectiveness of our circulatory systems, including the ever-important capillaries.

By maintaining a healthy diet without excessive fats, getting regular exercise and natural supplements, we can greatly strengthen capillary walls. This in turn leads to more efficient functioning of our many vital organs, and thus overall systemic health.