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 […]

Acute fatty liver of pregnancy (AFLP) has been found to be associated in some cases with an abnormality of fatty-acid metabolism. This abnormality is a deficiency of the enzyme long-chain-3-hydroxyacyl-CoA dehydrogenase (LCHAD). The mother (and father) have 50% of normal LCHAD activity and the fetus has no LCHAD activity. The metabolic disease in the baby’s […]

EBS (epidermolysis bullosa simplex): See: Epidermolysis bullosa simplex.

One of four vessels that carry aerated blood from the lungs to the left atrium of the heart. (The four are the right and left superior and inferior pulmonary veins). The pulmonary veins are the only veins that carry bright red oxygenated blood.

Any substance that can cause severe organ damage or death if ingested, breathed in, or absorbed through the skin. Many substances that normally cause no problems, including water and most vitamins, can be poisonous if taken in excessive quantity. Poison treatment depends on the ‘substance.

Mucosa-associated lymphoid tissue.