huk - Each month, approximately 1000 primary oocytes will...

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Oogenesis Oogenesis occurs in the ovary. Each of the divisions in humans is unequal. During the first meiotic division, a large secondary oocyte and a small polar body are produced. The secondary oocyte will divide to produce an egg and a polar body. The first polar body may divide to produce two more polar bodies. Although the polar bodies are very small and nonfunctional, they contain a full set of chromosomes. The photograph below shows a cross section of a rabbit ovary X 40. The primary oocyte is contained within a structure called a follicle. As the follicle enlarges, it produces hormones. During ovulation, the follicle ruptures and, in humans, releases the secondary oocyte. Meiosis in human females begins before person is born but stops in prophase I and does not resume until after puberty.
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Unformatted text preview: Each month, approximately 1000 primary oocytes will to mature but most will die. Ovulation occurs approximately once every 28 days. Females ovulate approximately 400 times during their lifetime. Secondary oocytes are released at ovulation. The second meiotic division resumes after penetration by sperm. In humans, secondary oocytes are fertilized. Eggs are produced only after fertilization of a secondary oocyte. In the diagram above, the first polar body produced after the first meiotic division did not divide again. Women are born with all of the primary oocytes that they will ever have (2 million). At puberty, there are approximately 400,000 left. Some chromosomal abnormalities associated with maternal age may be due to the long time they remain paired during prophase I....
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This note was uploaded on 12/15/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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huk - Each month, approximately 1000 primary oocytes will...

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