Step 1. Neurons in the hypothalamus release
gonadotropin-releasing hormone (GnRH).
Step 2. GnRH causes the release of
follicle-stimulating hormone (FSH) and
luteinizing hormone (LH) from the anterior pituitary gland.
Step 3. FSH and LH promote cell division in the
seminiferous tubules of the testes.
Seminiferous tubules wind around themselves within little compartments of the testes. Seminiferous tubules are lined with Sertoli cells, and Sertoli cells provide nourishment for developing sperm cells. FHS, or follicle stimulating hormone, acts on Sertoli cells specifically. It is here that stem cells divide so that the immature sperm have half the normal amount of DNA, instead of the normal amount that the stem cells started with.
This is also where:
- Microtubules grow to form a tail
- The midpiece packs with mitochondria so that the sperm has plenty of energy for swimming
- The Golgi apparatus forms the acrosome on the head of the sperm (the acrosome contains enzymes that will allow the sperm to penetrate the oocyte's zona pellucida and fertilize the oocyte)
Step 4. Leydig cells provide sufficient
testosterone to mature sperm cells.
Testosterone helps the sperm cells get rid of unnecessary organelles. Each sperm has one job: To get to the oocyte first. Most organelles just slow the sperm down, so they are jettisoned.
Step 5. Mature sperm cells move to the epididymis to become motile.
Mature sperm cells aren't much good unless they can move; the epididymis is where sperm gain motility. They are then stored until arousal.
