Dictionary

horizontal Parallel to the floor; a plane that passes through the standing body parallel to the floor.

zooparasite A living parasite, such as a worm or protozoa.

zoophilia A sexual disorder (paraphilia) that involves an abnormal desire to have sexual contact with animals. See also paraphilia.

zygoma The bone that forms the prominence of the cheek. Also known as zygomatic bone, zygomatic arch, malar bone, and yoke bone.

zygomatic arch See zygoma.

zygomatic bone See zygoma.

zygomycosis A potentially fatal, dangerous infection that is caused by various fungi from the class Zygomycetes. Zygomycosis is seen most often in patients who are already ill with diseases that suppress the immune system, such as AIDS, burn patients, patients taking corticosteroids, and those with poorly controlled diabetes. If unchecked, the fungal infection can spread…

zygote The cell that is formed by the union of a male sex cell (sperm) and a female sex cell (an ovum). The zygote develops into the embryo, as instructed by the genetic material within the unified cell. The unification of a sperm and an ovum is called fertilization. See also ovum; sperm.

zygote intrafallopian transfer An assisted reproductive procedure for the treatment of infertility in which a woman’s eggs are removed and fertilized with sperm in the laboratory, and the fertilized egg (zygote) is placed into the fallopian tube using a laparoscopic procedure. Abbreviated ZIFT. Like IVF and GIFT, ZIFT involves stimulation of the ovaries to produce…

ascending Going upward. For example, the ascending aorta is the portion of the aorta that ascends, going upward as it leaves the heart to form the beginning of the arch of the aorta.

descending Going down. For example, the descending aorta is the portion of the aorta that descends, going downward from the top of the arch of the aorta.

external Situated on the outside.