CK12 Life Science

(Marvins-Underground-K-12) #1

Figure 22.4: This diagram shows how an egg and its follicle develop in an ovary. After it
develops, the egg leaves the ovary and enters the Fallopian tube. The empty follicle becomes
a structure called a corpus luteum. ( 8 )



  1. Ovulation

  2. Empty follicle changing into corpus luteum

  3. Corpus luteum breaking down


If a sperm unites with the egg while it is passing through the Fallopian tube, the egg finally
completes meiosis. This results in two daughter cells that are different in size. The smaller
cell is called a polar body. It contains very little cytoplasm. It soon breaks down and
disappears. The larger cell is the egg. It contains most of the cytoplasm. You can watch
an animation of all the steps of egg production athttp://www.pennhealth.com/health_
info/animationplayer/egg_production.html


The Monthly Cycle


Egg production by the ovary is part of the menstrual cycle. Themenstrual cycleis a
series of changes in the reproductive system of mature females that repeats every month. It
includes events that occur in the uterus as well as the ovary.

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