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 […]

Erythema dose: The amount of radiation which, applied to the skin, makes it turn temporarily red (erythematous).

A method of treating food by heating it to a certain point to kill pathogenic (disease-causing) organisms but not harm the flavor or quality of the food. Milk is pasteurized by heating it to about 145°F (63°C) for 30 minutes or, using the “flash” method, by heating it to 160°F (71°C) for 15 seconds, followed […]

Calor: Heat, one of the four classic signs of inflammation together with dolor, rubor, and tumor (pain, redness, and swelling, respectively).

1. The killing of a person. 2. Strictly speaking, the killing of a man. femicide. From the Latin meaning murderer, from homo, man + caedere, to kill.

Abnormally low levels of the male sex hormone testosterone in the blood. Testosterone is produced by the testes and to a lesser extent by the adrenal glands. Testosterone encourages the development of male sexual characteristics at puberty, stimulates the activity of the male secondary sex characteristics, drives the production of sperm, and is involved in […]