Male reproductive system

• Sexual Reproduction

  • Humans reproduce sexually —> where a male and female gamete (sex cells) join
  • Gametes are produced in gonads (specialised sex organs)
  • Fertilisation - the fusion of a male and female gamete. This produces a zygote.

  Reproductive organs

  • Primary sex organs - produce gametes (testes and ovaries)
  • Secondary sex organs - other organs essential for reproduction (gamete storage, ferilization, foetal development)
• Testes

  • Male gonads - 2 testicles or testes
  • Spermatozoa (sperm) production
  • Testes are held and supported in a skin covered pouch called the scrotum. The scrotum in internally divided into 2 sacs.
  • Sperm production 2*C lower than body temp
  • With cold temp, scrotum constricts (smooth muscle contraction in wall) and brings testes closer to the body for warmth.
• • Testes divided internally into 200-300 lobules (compartments) filled with fine tubes called seminiferous tubules. They are lined with cells that produce sperm.
  • Between the seminiferous tubules are cluster of interstitial cells that secret the male hormone testosterone.
  • Seminiferous tubules in each lobule join to form a short tubule. These tubules join to form the epididymis which is 5-6 metres in length. Sperm is stored here for up to a month are production where they mature.
  • The epididymis becomes the vas defers which carries the sperm away from the testis.
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  Male reproduction

  • The vas deferents form each teste extend upward, loop behind the bladder and join to form the urethra.
  • This runs through the penis and transport both urine and semen
• Erectile tissue

  • The penis contains connective tissue that has a very rich blood supply.
  • This erectile tissue has a large number of sponge-like spaces which fill with blood during sexual arousal causing the penis to enlarge and become erect.
• The Penis

  • The penis is comprised of the shaft, head/glans and the foreskin (skin that covers the head)
• Semen

  • Semen - liquid which nourishes and aids the transport o sperm. A mixture of secretions form

  1. Seminal vesicles secrete a fluid rich in sugars that make up 60% of volume
  2. Prostate gland secretes a thin, mildly, alkaline fluid
  3. Bulbourethral glands secrete a clear mucus which acts as a lubricant of the urethra