Health

1. Health Growth and Development Menstruation Spermatogenesis Fertilization Arabella, Daisy and Scott

2. Growth and Development Growth and development can sometimes be a touchy subject for kids to learn. But what we have to remember is that we are learning about how to take care of our bodies and how to keep our bodies healthy. First Menstruation

3. What Is Menstruation Menstruation is the shedding of the uterine lining (endometrium). Once a girl hits puberty(usually starting between ages 8 and 13) it occurs on a regular basis. About once a month, an egg leaves from one of the ovaries this process is called ovulation. The egg travels down one of the fallopian tubes toward the uterus. Days before the egg leaves the ovaries the uterus builds up its lining with blood and tissue. If the egg is fertilized by sperm cell , it travels to the uterus and attaches to the cushiony wall of the uterus and grows into a baby. But if the egg is not fertilized witch is the usually the case during a woman’s monthly cycle it does not attach to the uterus wall and the uterus sheds the blood and tissue lining. The blood tissue and unfertilized egg leave the uterus going through the vagina on the way out of the body.

4. Menstruation Continued This cycle usually lasts for 3 to 7 days a month and will keep happing for several more years until the woman reaches menopause and will no longer release eggs from her ovaries. Next Spermatogenesis

5. Spermatogenesis Spermatogenesis is the process by which male primary germ cells undergo division, and produce a number of cells called spermatocytes, from which the primary spermatocytes are derived. Each primary spermatocyte divides into two secondary spermatocytes, and each secondary spermatocyte into two spermatids or young spermatozoa. These develop into mature spermatozoa, also known as sperm cells. The primary spermatocyte gives rise to two cells, the secondary spermatocytes , and the two secondary spermatocytes by their subdivision produce for spermatozoa.

6. Spermatogenesis Spermatozoa are the mature male gametes in many sexually reproducing organisms. Spermatogenesis is the male version of gametogenesis. In mammals it occurs in the male testes and epididymis in a stepwise fashion, and for humans takes approximately 64 days. Spermatogenesis is highly dependent upon optimal conditions for the process to occur correctly, and is essential for sexual reproduction. It starts at puberty and usually continues uninterrupted until death , although a slight decrease can be discerned in the quantity of produced sperm with increase in age. The entire process can can be broken up into several distinct stages, each corresponding to a particular type of cell.

7. Fertilization Fertilization is when the egg is released from the ovary. The egg travels to the fallopian tube. The sperm that has been ejected into the vagina swim into the opening of the cervix and up along the uterus and toward the egg in the fallopian tube. When the sperm meet the egg one sperm will penetrate into the egg. This process is called conception. After the egg attaches to the uterus it starts breaking up into tiny cells to make a baby.

8. Bibliography • http://deerparkhpe.wikispaces.com/7-1+HEALTH+2010-11 • http://kidshealth.org/teen/sexual_health/girls/menstruation.html • http://womenshealth.about.com/od/menstruation/Menstruation.htm • http://www.embryology.ch/anglais/cgametogen/spermato01.html • http://www.britannica.com/EBchecked/topic/559418/spermatogenesis • http://www.britannica.com/EBchecked/topic/559418/spermatogenesis • http://www.hc-sc.gc.ca/index-eng.php • http://www.google.ca/