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 […]

Cholestasis with peripheral pulmonary stenosis: Also known as arteriohepatic dysplasia or Alagille syndrome, this ia a genetic disorder characterized by yellowing of the skin (jaundice) in the newborn period, liver disease with cholestasis, peripheral pulmonic stenosis and unusual face. Children with Alagille syndrome usually present with jaundice (yellowing of the skin and whites of the […]

they produce eggs (ova) and female hormones. Each month, during the menstrual cycle, an egg is released from one ovary. The egg travels from the ovary through a fallopian tube to the uterus. The ovaries are the main source of female hormones (estrogen and progesterone). These hormones control the development of female body characteristics, such […]

Fracture, clay-shoveler’s: An uncommon breakage of the spine of the vertebrae from the lower neck or upper back as a result of stress. Clay-shoveler’s fracture usually occurs in laborers who perform activities involving lifting weights rapidly with the arms extended. Examples of these activities include shoveling soil, rubble or snow up and over the head […]

This is trench mouth, a progressive painful infection with ulceration, swelling and sloughing off of dead tissue from the mouth and throat due to the spread of infection from the gums. Certain germs (including fusiform bacteria and spirochetes) have been thought to be involved, but the full story behind this long-known disease is still not […]

The tiny area between the two layers of the pleura (the thin covering that protects and cushions the lungs) between the lungs and chest cavity. The pleural space is normally filled with a small amount of fluid.