A sex chromosome in certain animals, such as chickens, turkeys, and moths. In humans, males are XY and females XX, but in animals with a Z chromosome, males are ZZ and females are WZ.

Zeta-chain-associated protein kinase 70. A member of the protein tyrosine kinase family, ZAP-70 is normally expressed in T cells and natural killer cells and has a critical role in the initiation of T-cell signaling. ZAP-70 is expressed in T cells and tumors of T-cell lineage. A high level of ZAP-70 expression appears restricted to T-cell […]

‘When you hear hoof beats, think of horses, not zebras.’ For example, when someone develops a mild transient cough, a virus infection is the most logical and likely cause, and tuberculosis is a zebra.

A gene that is lethal (fatal) for the zygote, the cell formed by the union of a sperm (male sex cell) and an ovum (female sex cell). The zygote would normally develop into an embryo, as instructed by the genetic material within the unified cell. However, a zygotic lethal gene scotches prenatal development at its […]

A technique in which a woman’s egg is fertilized outside the body, then implanted in one of her fallopian tubes. This technique is one of the methods used to overcome infertility, the inability of couples to produce offspring on their own. First, the egg and the male sperm needed to fertilize it are harvested. Then […]

Barotrauma: Trauma caused by rapid or extreme changes in air pressure, especially affecting enclosed cavities within the body such as the middle ear (otic barotrauma), the sinuses (sinus barotrauma), and the lungs (pulmonary barotrauma). See also: Otic barotrauma; Sinus barotrauma; and Pulmonary barotrauma.

Apposition: The word “apposition” has several senses including the act of adding or accretion and also the putting of things in juxtaposition, or side by side. Growth by apposition is a mode of growth that is characteristic of many tissues in the body by which nutritive matter from the blood is transformed on the surface […]

Surgery to remove all or part of the kidney, for example, because of cancer.

Fungiform papilla: The fungiform papillae are broad flat structures that house taste buds in the central portion of the dorsum (back) of the tongue. These papillae were thought to resemble a fungus: a little mushroom. Fungiform means mushroom-shaped. From fungi-, fungus + forma, shape.

A wart by another name, a local growth of the outer layer of the skin (the epidermis) caused by a virus. The virus of warts (a human papillomavirus) is transmitted by contact. The contact can be with a wart on someone else or one on oneself (autoinoculation). Warts that occur on the hands or feet […]