Spermatogenesis and Oogenesis

• Spermatogenesis


  Process of producing sperm (spermatozoa)
• Spermatogenesis


  • Takes place every day
  • Occurs in the testes
  • Production from spermatogonia
  • In millions every day
  • Sperm are motile
• Spermatogenesis


  1. Begins with spermatogonia (diploid cells)

  2. Forms primary spermatocyte (diploid)

  3. Undergoes first meiotic division

  4. Results in two haploid secondary spermatocytes

  5. Undergoes second meiotic division

  6. Yields four spermatids

  7. Mature into sperm with flagella
• Spermatogenesis is a continuous process


  Occurring after puberty till death
• Spermatogenesis = sperm production
• Spermatogenesis starts at puberty, continues into old age
• Spermatogenesis begins with spermatogonium, ends with eight equal-sized sperm cells
• Oogenesis


  Process of producing egg cells (ovum)
• Oogenesis


  • Takes place once per month
  • Takes place in the ovaries
  • A few stages occur in the oviduct
  • Only one ovum is released once a month
  • Egg cells are nonmotile
• Oogenesis


  1. Begins with oogonia (diploid cells)

  2. Forms primary oocyte (diploid)

  3. Starts first meiotic division but arrests

  4. Upon follicle development, completes first division

  5. Yields secondary oocyte (haploid) and polar body

  6. Begins second meiotic division but arrests

  7. If fertilized, completes second division

  8. Results in mature ovum and another polar body
• Early stage of oogenesis

  Occurs after fetal period (prior to birth)
• Rest of oogenesis


  Occurs after puberty until menopause
• Oogenesis = production of egg cells (ovum)
• In oogenesis, one oogonium can produce two egg cells
• Process of Spermatogenesis and Oogenesis

  A) Fertilization

  B) Maturation

  C) polar body

  D) Sperm

  E) haploid

  F) Primary

  G) Spermatogenesis

  H) Oogenesis