Mindblown: a blog about philosophy.

Done in accordance with the conscious will of the individual. The opposite of involuntary. The terms “voluntary” and “involuntary” apply to the human nervous system and its control over muscles. The nervous system is divided into two parts — somatic and autonomic. The somatic nervous system operates muscles that are under voluntary control. The autonomic (automatic or visceral) nervous…

Pertaining to the palm or the sole. For example, the volar surface of the forearm is the portion of the forearm that is on the same side as the palm of the hand.

To urinate. The term void is also sometimes used to indicate the elimination of solid waste (defecation).

The voice box, or larynx, is the portion of the respiratory (breathing) tract containing the vocal cords which produce sound. It is located between the pharynx and the trachea. The larynx, also called the voice box, is a 2-inch-long, tube-shaped organ in the neck. We use the larynx when we breathe, talk, or swallow. Its outer wall of cartilage forms the area…

A clear, jelly-like substance that fills the middle of the eye. Also called the vitreous humor, “humor” in medicine referring to a fluid (or semifluid) substance.

The word “vitamin” was coined in 1911 by the Warsaw-born biochemist Casimir Funk (1884-1967). At the Lister Institute in London, Funk isolated a substance that prevented nerve inflammation (neuritis) in chickens raised on a diet deficient in that substance. He named the substance “vitamine” because he believed it was necessary to life and it was…

One of two naturally occurring fat-soluble vitamins (vitamin K1 and vitamin K2) needed for the clotting of blood because of an essential role in the production of prothrombin (a clotting factor). The term vitamin A may also refer to a synthetic compound that is closely related chemically to the natural vitamins K1 and K2 and has similar biological activity. Vitamin K is…

A vitamin produced by the body when exposed to ultraviolet light or obtained from dietary sources. Vitamin D3 is a hormone that has an important role in calcium and phosphorus metabolism. Technically, vitamin D3 is not a vitamin because the body can produce it. Also known as cholecalciferol.

A steroid vitamin which promotes the intestinal absorption and metabolism of calcium and phosphorus. Under normal conditions of sunlight exposure, no dietary supplementation is necessary because sunlight promotes adequate vitamin D synthesis in the skin. Deficiency can lead to bone deformity (rickets) in children and bone weakness (osteomalacia) in adults. Vitamin D comes from the diet (eggs, fish, and dairy products)…

An essential nutrient found mainly in fruits and vegetables. The body requires vitamin C to form and maintain bones, blood vessels, and skin. Vitamin C is also known as ascorbic acid. Vitamin C is a water-soluble vitamin, one that cannot be stored by the body except in insignificant amounts. It must be replenished daily. Vitamin C helps produce collagen, a protein…