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Male Reproductive System

Male Reproductive System. Biology 12. Testosterone. a male sex hormone produced by the interstitial cells of the testes. Spermatogenesis. the process by which spermatogonia (immature sperm cells) divide and differentiate into mature sperm cells. Gonadotrophic hormones.

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Male Reproductive System

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  1. Male Reproductive System Biology 12

  2. Testosterone • a male sex hormone produced by the interstitial cells of the testes.

  3. Spermatogenesis • the process by which spermatogonia (immature sperm cells) divide and differentiate into mature sperm cells.

  4. Gonadotrophic hormones • hormones produced by the pituitary gland that regulate the functions of the testes in males and the ovaries in females.

  5. Follicle stimulating hormone • FSH in males is a hormone that increases sperm production.

  6. Luteinizing hormone • LH in males is a hormone that regulates the production of testosterone.

  7. Gonadotropin-releasing hormone • GnRH is a hormone released by the hypothalamus that stimulates the secretion of LH and FSH from the pituitary gland.

  8. 1. What happens to animals when they are castrated? • Castration involves the removal of the testes from the male species. • This removes the source of testosterone for the animal. • It is a common practice when animals are being bred for meat because it makes the meat more tender and tasty. • It also removes aggressive behavior, sex drive and the animal is sterile.

  9. 2. Fully explain the role of testosterone in males. • Testosterone is a male sex hormone that is produced in the testes and it is the most potent and abundant male hormone. 1. Testosterone is responsible for spermatogensis, the process of producing mature sperm cells in the interstitial cells of the testes.

  10. 2. Testosterone is responsible for the development of secondary sex characteristics that develop during puberty. Changes include: • maturation of the testis and penis • an increase in sex drive • development of facial and body hair • growth of larynx (voice box) causing deepening of the voice • Strengthening of the muscles • Increase in secretion of sebum (oil) leading to skin problems.

  11. 3. Explain how the negative feedback system controls the maintenance of sperm cells and testosterone levels. • The negative feedback loop ensures that adequate numbers of sperm cells and testosterone levels are maintained. • The production of sperm and testosterone in the testes is controlled by the hypothalamus and the pituitary. • The hypothalamus releases GnRH which stimulates the release of LH and FSH from the pituitary gland.

  12. LH promotes the production of testosterone in the interstitial cells. • FSH targets the seminiferous tubules and stimulates the production of sperm. • Once the levels of testosterone reach a high level the hypothalamus receives the message that there is enough testosterone and this activates the negative feedback loop. • The hypothalamus releases less GnRH which then inhibits release of LH from the pituitary.

  13. 4. What do we know about the feedback loop for production of sperm? • We do not have a good understanding at present of how the feedback loop functions for the production of sperm. • Scientists believe that FSH acts on the Sertoli cells that produce a peptide hormone called inhibin that sends a message via the feedback loop to the pituitary gland where it inhibits the production of FSH.

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