• Z chromosome

    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.

  • ZAP-70

    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 […]

  • Zebra

    ‘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.

  • Zygotic lethal gene

    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 […]

  • Zygote intrafallopian transfer (ZIFT)

    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 […]

  • Tonsils

    Small masses of lymphoid tissue at the back and on both sides of the throat.

  • Coronary arteries

    Coronary arteries: The vessels that supply the heart muscle with blood rich in oxygen. They are called the coronary arteries because they encircle the heart in the manner of a crown. The word “coronary” comes from the Latin “corona” and Greek “koron” meaning crown. Like other arteries, the coronaries may be subject to arteriosclerosis (hardening […]

  • TPH2

    Tryptophan hydroxylase 2, also known as neuronal tryptophan hydroxylase (NTPH), the key rate-limiting enzyme in the synthesis of serotonin (5-hydroxytryptamine, or 5HT). 5HT is causally involved in numerous activities in the central nervous system, and it also has other functions including the maintenance of vascular tone and gut motility. The TPH2 gene is on chromosome […]

  • Heparin-induced thrombocytopenia

    Low blood platelet count as a result of the medication heparin. HIT (Heparin induced thrombocytopenia) is caused by the body forming antibodies to Heparin when it is bound to platelet factor4 (PF4) – a protein in the blood. These antibodies bind to the combination of Heparin and PF4 and activate platelets which in turn clump […]

  • Child abuse, verbal

    Also known as emotional child abuse, this is the third most frequently reported form of child abuse (after child neglect and physical child abuse), accounting 17% of all cases of child abuse. It is likely that emotional child abuse is greatly underreported, since it can be difficult to detect and difficult to document. Emotional child […]