Human+Reproduction

= Human Reproduction =

All things must reproduce in order to keep their species going. The reproductive organs are in the body from birth, but they don't become fully functional until puberty, a period of rapid growth and sexual maturation.

The primary function on the female reproductive system is to create eggs that could potentially turn into a zygote when fuzed with a sperm and eventually grow into a baby. Production of eggs starts in the ovaries. Ova are created in a process called oogenesis where one ovum and three polar bodies are produced. In the ovaries there are thousands of follicles, cells surrounding eggs, in the ovaries that help the egg to mature. Once it has fully matured, a process called ovulation occurs. Ovulation is the process in which a single mature egg is released and is brought through a passageway called the fallopian tubes. An egg can be fertilized if given the opportunity in the fallopian tubes, but after a few days in the fallopian tubes the egg will move on to the uterus. The uterus is the place where a fertilized egg will stay to receive nutrients from inside of the endometrium, the lining in the uterus. If an egg is not fertilized it will go through a process called menstruation. In menstruation, the unfertilized egg will travel from the uterus into the cervix, the outer end of the uterus. From the cervix, it will go through the vagina, the passageway to the outside of the body.

The male reproductive system's main function is to create sperm that will find and fertilize an egg. The sperm is created in the testes in the process of spermatogenesis. Each round of spermatogenesis creates four sperm cells. Inside each of the testes are hundreds of seminiferous tubules which make the sperm. Once enough sperm is produced, they are moved to the epididymis where they fully mature and are stored until needed. Some of the sperm will now move onto the vas deferens which will eventually merge with another passageway called the urethra. The urethra leads to the penis, which will take the sperm outside of the body. Seminal fluid is also produced and helps to nourish and protect the sperm.

Animation:
Comparisons of Oogenesis and Spermatogenesis: http://wps.aw.com/bc_martini_eap_4/40/10469/2680298.cw/content/index.html

Helpful links:
More on Oogenesis: http://www.ncbi.nlm.nih.gov/books/NBK10008/ More on Spermatogenesis: http://www.embryology.ch/anglais/cgametogen/spermato03.html