Polar body

A polar body is a structure produced when an early egg cell, or oogonium, undergoes meiosis. In the first meiosis, the oogonium divides its chromosomes evenly between the two cells but divides its cytoplasm unequally. One cell retains most of the cytoplasm, while the other gets almost none, leaving it very small. This smaller cell is called the first polar body. The first polar body usually degenerates. The ovum, or larger cell, then divides again, producing a second polar body with half the amount of chromosomes but almost no cytoplasm. The second polar body splits off and remains adjacent to the large cell, or oocyte, until it (the second polar body) degenerates. Only one large functional oocyte, or egg, is produced at the end of meiosis.

Source: Stem Cell Information, NIH, USDHHS

YOU MAY ALSO LIKE

Poland Syndrome

A rare developmental disorder characterized by underdevelopment or absence of the pectoralis muscle in one side of the chest, usually associated with…

POL Gene

This gene is involved in the replication of the retroviral genome.

Pokeweed Mitogen

A group of proteins isolated from the roots of pokeweed, Phytolacca americana, with hemagglutinating and mitogenic properties. Pokeweed mitogen is particularly mitogenic…

Poisson Distribution

A distribution function used to describe the occurrence of rare events or to describe the sampling distribution of isolated counts in a…

Poisoning

A condition or physical state produced by the ingestion, injection or inhalation of, or exposure to a deleterious agent.

Poison Ivy, Oak and Sumac

If you spend time outdoors, chances are you have been bothered by poison ivy, poison oak or poison sumac at some…