The spelling of "capillary permeabilities" can be explained using IPA phonetic transcription. The word is pronounced /kəˈpɪləri pɜːrmiəˈbɪlɪtiz/, with the stress on the second syllable of "capillary" and the first syllable of "permeabilities". The "a" in "capillary" is pronounced like the "a" in "cat", while the second "i" is pronounced like the "i" in "sit". The "e" in "permeabilities" is pronounced like the "e" in "pen", and the "i" is pronounced like the "i" in "bit".
Capillary permeabilities refer to the ability of capillaries, the smallest blood vessels in the body, to allow the passage of substances in and out of the bloodstream. These permeabilities are determined by the characteristics and structure of the capillary walls.
Capillaries are composed of a single layer of endothelial cells, which are thin and have small gaps between them. These gaps, known as interendothelial junctions, can vary in size and are the main sites for the exchange of nutrients, gases, waste products, and other substances between the blood and surrounding tissues.
The magnitude of capillary permeabilities can vary depending on the specific needs and functions of different tissues and organs in the body. Some capillaries, such as those found in the liver, kidney, and lungs, have high permeabilities to allow efficient exchange of materials. They have larger interendothelial gaps and may also possess specialized structures like fenestrations (small pores) or sinusoids (wider capillary spaces).
Capillary permeabilities are influenced by various factors, including the size and charge of molecules, blood pressure, tissue metabolic activity, and the presence of specific transporters and channels. These factors determine the selectivity and magnitude of substances that can cross the capillary wall.
Alterations in capillary permeabilities can occur in certain medical conditions, such as inflammation or diseases affecting the integrity of the capillary walls. Increased capillary permeabilities can lead to abnormal leaking of fluid and proteins into tissues, causing edema (swelling). Conversely, decreased permeabilities can affect the delivery of nutrients and oxygen to tissues, impairing their proper functioning.
The word "capillary" is derived from the Latin word "capillaris", meaning "hair-like". It is used to refer to the tiny blood vessels in the body that are so narrow and thin that they resemble hairs.
The term "permeabilities" is derived from the Latin word "permeabilis", meaning "able to be passed through". It refers to the ability or property of a substance or vessel to allow another substance to pass through it.
Therefore, "capillary permeabilities" combines these two terms to describe the ability of substances to pass through the walls of capillaries, the smallest blood vessels in the body.