MC

Male and Female Reproductive Systems

Male Reproductive System

  • Male Reproductive Structures
    • External and internal genitalia.
    • Only system not essential for sustaining life.
    • Gonads produce gametes (sperm).

External Genitalia

  • Penis
    • Contains erectile tissue; deposits sperm into the female vagina.
    • Urethra conducts semen to the exterior.
  • Scrotum
    • Encases the testes.

Internal Genitalia

  • Ductus deferens
    • Conducts sperm from the epididymis to the prostate.
  • Seminal gland (seminal vesicle)
    • Secretes fluid contributing to semen volume.
  • Prostate
    • Secretes fluids and enzymes into semen.
  • Bulbourethral gland
    • Lubricates the penis tip with pre-ejaculatory fluid.
  • Epididymis
    • Site of sperm maturation.
  • Testis
    • Produces sperm and hormones (testosterone).

Sperm Transportation

  • Sperm follows the path: testis ➔ epididymis ➔ ductus deferens ➔ ejaculatory duct ➔ urethra.

Accessory Organs

  • Seminal glands, prostate, and bulbourethral glands secrete fluids into the reproductive tract to form semen.
  • Urethra passes through the penis to exit the body.

Testes Development

  • Form inside the body adjacent to the kidneys during fetal development.
  • Connective tissue bands change position, positioning each testis into the scrotum.

Scrotum and Associated Structures

  • Scrotal Cavity
    • Houses the testes, separated by the scrotal septum.
  • Dartos Muscle
    • Smooth muscle that elevates testes.
  • Cremaster Muscle
    • Pulls testes closer during arousal or cold temperatures.
  • Spermatic Cords
    • Contain the ductus deferens, blood vessels, and nerves.
  • Inguinal Canal
    • Can be prone to hernias; a weakness in the abdominal wall.

Internal Organization of the Testes

  • Seminiferous tubules
    • Site of sperm production, connect to the rete testis and epididymis.
  • Leydig cells
    • Produce androgens (e.g., testosterone).

Spermatogenesis

  • Process involves:
    • Mitosis/cytokinesis, Meiosis, and Spermiogenesis.
  • Mitosis:
    • Spermatogonia divide to form one primary spermatocyte and another remains as a stem cell.
  • Meiosis:
    • Produces four haploid spermatids from each primary spermatocyte.
    • Takes 24 days; two meiotic divisions:
    • Meiosis I: Primary to secondary spermatocytes (haploid).
    • Meiosis II: Secondary to spermatids.
  • Spermiogenesis:
    • Maturing of spermatids into sperm; occurs over 24 days.

Sperm Structure

  • Head: Contains nucleus and acrosome (enzymes for fertilization).
  • Neck: Contains centrioles.
  • Middle piece: Contains mitochondria for ATP.
  • Tail (flagellum): For movement.

Male Reproductive Tract

  • Receives secretions from seminal, prostate, and bulbourethral glands.
  • Activation of Sperm:
    • Capacitation process for increased motility and fertilization ability.
    • Sperm gains maturity within the epididymis before ejaculation.

Penis Structure and Function

  • Conducts urine and semen to the exterior and delivers semen into the female’s vagina.

Regions

  • Root: Fixed portion attaching to body wall.
  • Body: Tubular, movable part.
  • Glans penis (head): Surrounds external urethral orifice.

Erectile Tissue

  • Corpora cavernosa: Two cylindrical masses.
  • Corpus spongiosum: Surrounds the urethra; expands to form the glans.
  • Erection Process:
    • Increased blood flow causes engorgement during sexual arousal.

Hormonal Regulation of Male Reproductive Function

  • Hypothalamus: Secretes GnRH, stimulating LH and FSH production from the anterior pituitary.
  • LH: Stimulates interstitial cells in testes to secrete testosterone.
  • FSH: Stimulates nurse cells, promoting spermatogenesis.
  • Inhibin: Provides feedback control to regulate spermatogenesis.

Female Reproductive System

  • Overall Functions:
    • Produce sex hormones, functional gametes (oocytes), protect/support developing embryos, maintain fetus, and nourish infants.

Female Reproductive Structures

  • External Genitalia (Vulva):
    • Clitoris, labia, mons pubis.
  • Mammary Glands:
    • Produce milk post childbirth.

Internal Genitalia

  • Ovaries: Produce immature oocytes and sex hormones.
  • Uterine tubes: Carry oocytes; fertilization occurs here generally.
  • Uterus: Supports the embryo/fetus and provides nourishment during development.
  • Vagina: Receives sperm and serves as the birth canal.

Oogenesis

  • Formation of oocytes, begins in fetal development and finished at ovulation post-puberty.
  • Meiosis: Similar to spermatogenesis but results in one functional ovum and polar bodies from each primary oocyte.

Uterine Cycle

  • Monthly cycle that prepares the endometrium for potential pregnancy.
  • Phases:
    • Menstrual Phase: Sloughing of the endometrial layer.
    • Proliferative Phase: Repair and growth of the endometrium.
    • Secretory Phase: Secretion from uterine glands to support a possible embryo.

Hormonal Regulation of Female Reproductive Cycle

  • Controlled by changes in hormone levels from hypothalamus and pituitary affecting ovarian and uterine cycles.

Conclusion

  • Understanding male and female reproductive systems is crucial for comprehending reproduction, growth, and development processes, as well as associated health risks and hormonal interactions.