Male

• Name the main components of the male reproductive system.

  • main components include the penis, bladder, prostate gland, bulbourethral gland, testis, vas deferens, seminal vesicle, and accessory glands.
• What are the three parts of the penis?

  1. Root: The proximal, fixed part, containing erectile tissues (two crura and bulb) and muscles (ischiocavernosus and bulbospongiosus).
  2. Body: The free, cylindrical portion with two corpora cavernosa and one corpus spongiosum.
  3. Glans: The distal, conical part containing the external urethral orifice.
•  What are the two major quantifiable attributes of semen?

  1. The total number of spermatozoa, reflecting testicular sperm production and duct patency.
  2. The total fluid volume contributed by accessory glands, reflecting their secretory activity.
• List the contributions of the accessory glands to seminal plasma.

  • Seminal vesicles: ~70-75%
  • Prostate gland: 24-30%
  • Bulbourethral gland: ~1%
• What is the purpose of seminal plasma?

  • Protect and nourish spermatozoa.
  • Facilitate sperm transport along the vas deferens.
  • Protect sperm from the acidic vaginal environment.
• Name some key constituents of seminal plasma and their functions.

  • Fructose: Provides energy for sperm metabolism.
  • Citric acid: Acts as a calcium chelator.
  • Prostaglandins: Stimulate uterine contractions.
  • Zinc: Protects chromatin integrity.
  • Ascorbic acid: Acts as an antioxidant.
  • Glycerylphosphorylcholine: Substrate for phospholipid metabolism.
• What is spermatogenesis?


  •  It is the process of producing mature sperm cells (spermatozoa) from germ cells in the seminiferous tubules of the testes.
• Outline the stages of spermatogenesis.

  1. Spermatogonial phase (Mitosis): Spermatogonia divide to maintain the stem cell population and form primary spermatocytes.
  2. Spermatocyte phase (Meiosis):

  • Primary spermatocytes → Secondary spermatocytes → Spermatids (haploid).

  1. Spermatid phase (Spermiogenesis): Structural changes transform spermatids into motile spermatozoa.
• What is the role of Sertoli cells in spermatogenesis?

  • Provide structural and nutritional support.
  • Create a blood-testis barrier.
  • Secrete factors necessary for germ cell development.
• Describe the hormonal regulation of spermatogenesis.

  • FSH: Stimulates Sertoli cells to support spermatogenesis.
  • LH: Stimulates Leydig cells to produce testosterone.
  • Testosterone: Essential for spermatogenesis and development of secondary sexual characteristics.
• What is the Hypothalamic-Pituitary-Gonadal (HPG) axis?

  • Hypothalamus: Releases GnRH.
  • Pituitary gland: Releases LH and FSH in response to GnRH.
  • Leydig cells: Produce testosterone under LH stimulation.
  • Sertoli cells: Support spermatogenesis under FSH stimulation
• What factors contribute to a normal erection?

  • Sexual stimuli (visual, olfactory, tactile).
  • Sacral parasympathetic input (S2-S4): Causes arterial dilation, venous compression, and penile tumescence.
  • Neurochemicals: Dopamine, acetylcholine, nitric oxide (NO), oxytocin, and others.
• What role does nitric oxide (NO) play in erections?

  • NO is a vasodilator, relaxing penile blood vessels, facilitating increased blood flow and erection.
• How does male reproductive function change with age?

  • Testicular volume: Decreases from 29.7 ml in younger men to 20.6 ml in older men.
  • Sperm production: Reduces by 30% in elderly men.
  • Serum FSH: Increases threefold in men over 70 compared to those under 35.
  • Serum inhibin: Decreases by 75% in elderly men.
•  What is andropause?

  • Andropause, or male menopause, refers to the age-related decline in testosterone production and reproductive function in men.