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 […]

Bones of the trunk: The 51 trunk bones consist of 26 vertebrae, 24 ribs, and the sternum. The 26 vertebrae comprise 7 cervical, 12 thoracic, and 5 lumbar vertebrae, plus the sacrum and the coccyx. The 24 ribs comprise 14 true ribs, 6 false ribs, and 4 floating ribs. The sternum is the breastbone. Along […]

A triptan drug for the treatment of migraine. Marketed under the brand name Imitrex.

Dermatitis herpetiformis: an autoimmune condition that results in a chronic, itchy skin rash. Dermatitis herpetiformis is characterized by bumps and blisters occurring primarily on the forearms, knees, elbows, buttocks, back, or scalp. Most people with the condition also have gluten-sensitive enteropathy (celiac disease). It is most common in people of Northern European ancestry. The exact […]

Sunburn is an inflammation of the skin that develops in response to exposure to ultraviolet (UV) radiation from the sun or from tanning beds and booths that emit UV radiation. Sunburn is manifested by reddened, painful skin that may develop blisters. Sunburn early in life increases one’s risk of developing skin cancers later in life […]

The fluid that is discharged from the vagina for a week or so after childbirth. At first the lochia is primarily blood, followed by a more mucousy fluid that contains dried blood, and finally a clear-to-yellow discharge.