1. Sperm Production: Spermatogenesis http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter28/animation__spermatogenesis__quiz_1_.html

2. Spermatogenesis Sperm produced in testes which are located outside the body in order to help in temperature regulation (~3° lower temperature) In each testis are seminiferous tubules; near outer wall of tubules are germinal epithelial cells (cells of an organism whose function is to reproduce its kind) called spermatogonia Note: It takes 64-74 days for sperm to develop and every day ~100 million sperm are produced

4. Spermatogonia either go through mitosis to replace cells becoming sperm (type A) or go through meiosis to form 4 spermatozoa (type B)

5. Leydig cells – found in-between the tubules; after pituitary gland secretes LH, these cells respond by producing testosterone (key to sperm production) Sertoli cells – cells in the seminiferous tubules that assist in the development of sperm cells (Nurse cells)

7. Testis Tissue

8. Pseudo-colored scanning electron micrograph of seminiferous tubule

9. Process of Making Sperm: Spermatogenesis 1. Mitosis of Type A spermatogonia takes place to form a Type B spermatogonia 2. Type B spermatogonia then grows and becomes a primary spermatocyte 3. Primary spermatocyte undergos Meiosis I (forming the secondary spermatocyte) and Meiosis II (forming spermatids); both result in haploid cells 4. The spermatids then differentiate into spermatozoa (flagellum/acrosome)

11. Function of Hormones in spermatogenesis: LH – produced by pituitary gland; stimulates Leydig cells to produce testosterone Testosterone – produced by Leydig cells; promotes spermiogenesis (maturation of spermatids into spermatozoa) FSH – produced by pituitary gland; stimulates sperm production in seminiferous tubules; stimulates division and maturation of Sertoli cells

12. Head: Acrosome (organelle that contains enzymes necessary to penetrate the egg); Nucleus (haploid) Midpiece: Mitochondria (provide ATP for swimming) Tail: Flagellum (movement)