Medical Glossary Decoded

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.
Stands for zygote intrafallopian transfer. A method used to treat infertility in which an egg fertilized in vitro (outside the body) is placed into a woman's fallopian tube.
Also called Brill-Zinsser disease. It is a delayed relapse of epidemic typhus, caused by Rickettsia prowazekii.
The zona pellucida is the transparent, thick outer layer of the ovum in mammals that protects the ovum as it travels from the ovary to the uterus. In order to fertilize the egg the sperm first penetrate this outer layer.After fertilization the zona pellucida disappears, to permit implantation in the uterus.
An abnormal and persistent fear of animals.
The bone that forms the prominence of the cheek.
The cell formed by the union of a male sex cell (a sperm) and a female sex cell (an ovum). The zygote develops into the embryo.