Spermatogenesis and Oogenesis: Key Facts

Posted on Mar 6, 2025 in Biology

Key Facts About Spermatogenesis and Oogenesis

Spermatogenesis:

  1. The stage of spermatogenesis that lasts about one day is meiosis.
  2. Sperm is stored and continues its journey in the epididymis.
  3. Vasectomy is performed on the vas deferens.
  4. Characteristics of the seminal glands:
    • They are organs that secrete 60% of the volume of semen.
    • Secretion of fructose and citric acid.
    • Secretion of coagulating proteins.
  5. Characteristics of the prostate gland:
    • It secretes 20% of the volume of semen.
    • Secretion of clotting proteins.
    • Secretion of Ca and phosphate ions.
  6. Organs that contribute components to human semen: Cowper’s glands, Prostate.
  7. The following alteration that could not be considered a factor in male infertility: Damage to the urethra from the prostate.
  8. Sperm and egg similarities: The amount of genetic material.
  9. If a drug selectively destroys Leydig cells of a 7-year-old, the effects would be:
    • Underdevelopment of secondary sexual characteristics.
    • Low sperm production.
  10. Number of sperm produced from one spermatocyte: 4.
  11. Regarding Sertoli cells, it is correct that they:
    • Participate in the nutrition of germ cells.
    • Phagocytose the residual cytoplasm of spermatids undergoing cytodifferentiation.
    • Are more resistant to higher temperatures than germ cells.
  12. A comparison of human spermatogenesis and oogenesis shows that they differ in:
    • Spermatogenesis is a continuous process, and oogenesis is presented cyclically.
    • Oogenesis has stages of meiotic arrest, and spermatogenesis does not.
    • In spermatogenesis, the four haploid cells are functional, and in oogenesis, just one is.
  13. Duration of spermatogenesis: 74 days.
  14. Approximate volume and composition of semen:
    • 2 to 3 milliliters per ejaculation.
    • 20 to 150 million sperm per ml of semen.
  15. Hormones produced by Sertoli cells: Inhibin, Anti-Müllerian hormone.
  16. Qualities of sperm: Cells are self-mobile.
  17. Cells responsible for testosterone production: Leydig cells.
  18. What would happen to sperm production if a tumor completely prevented the function of the hypothalamus?: There would be none.
  19. The place where sperm formation occurs: Seminiferous tubules of the testes.
  20. A hormone that stimulates spermatogenesis: FSH.
  21. A hormone that stimulates Leydig cells: LH.

Oogenesis:

  1. The stage of maturation in oogenesis includes: All of the above.
  2. At fertilization, the oocyte completes its meiosis.
  3. Number of viable gametes in oogenesis: 1; and in spermatogenesis: 4.
  4. The site of oogenesis development: ovaries; and spermatogenesis: testes.
  5. Why is it said that in humans, the “egg” as such does not exist? Because the correct name when the egg is fertilized is zygote, not egg.
  6. Functions:
    • Acrosome: The front part of the sperm head produces hyaluronic acid, which dissolves the walls of the oocyte to allow entry.
    • Mitochondria: Produce energy for sperm.
  7. Are all sperm formed by a man genetically different? Yes, because there is genetic variability among sperm due to the crossing over of genetic material in prophase I.
  8. Consequences of lack of development of secondary sexual characteristics:
    1. Hypogonadism (genitals do not grow).
    2. No development of body hair.
    3. No voice change.