L3: Anatomy of the Reproductive System

• Gonads

  • Male: Testes
  • Female: Ovaries
• Gametes

  • Male: Sperm
  • Female: Ova or Egg
• Hormones

  • Male: Testosterone
  • Female: Progesterone and Estrogen
• Functions of Gonads

  • Produce egg and sperm cells
  • Transport and sustain these cells
  • Nurture the developing fetus
  • Produce hormones
• • If conditions are suitable, a sperm and egg fuse to become a fertilized egg (zygote)
  • Once fertilization has occurred, the female uterus provides a protective environment in which the embryo, later called the fetus, develops until birth.

  Nurture the developing fetus
• • Influence growth and development of many other organs and tissues in the body.
  • Play vital roles in the development and function of the:
  • reproductive organs
  • sexual behavior and drives


  Produce hormones
• chemicals that influence processes inside the body. In the concept of gonads, they provide secondary sex characteristics.

  Hormones
• • In males.
  • Produces sperm – male gametes
  • Testosterone – male hormone

  Testes
• • In females
  • Develops ova (eggs) – female gametes
  • Estrogen and Progesterone – female hormones

  Ovaries
• Fusion of sperm and egg cells that produces a zygote.

  Fertilization
• A main characteristic that differentiates a male reproductive system from a female’s is the external manifestation of the organs.

  • Outward manifestation brought about by the presence of the testes that’s away from the body.
  • Presence of the penis.
• • Have an exocrine function (sperm production)
  • Site of Spermatogenesis = Process of formation and development of sperm cells.
  • Have an endocrine function (testosterone production)


  Testes
• sperm production


  exocrine function
• testosterone production


  endocrine function
• There are 2 testes (Singular = testis) and they each have a hanged appearance
• Each testis is connected to the trunk via the spermatic cord which houses:

  • Blood vessels - supply of nourishment and oxygenation to the organ, transport nutrients
  • Nerves - allow activities to take place
  • Ductus (vas) deferens - ensure that the contents released are directed to where it’s needed.

  Testes
• coverings of the testes: Tunica albuginea and Septa


  Testes
• Fibrous connective tissue capsule that surrounds each testis

  Tunica albuginea
• • Extensions of the capsule (Tunica albuginea) that extend deeper into the testis and divide it into lobules.
  • Appropriate partition and proper placing/spacing.
  • Each lobule contains:
  • 1-4 Seminiferous Tubules


  Septa
• • The reason why the testes are away from the body is for it to maintain an adequate temperature for the viability of the sperm. Separated from the core.
  • Capable of producing sex hormones via the influence of the endocrine system (pituitary gland).

  Testes
• 1. Rete testis
  2. Ductus (vas) deferens
  3. Epididymis
  4. Spermatic cord
  5. Blood vessels and nerves
  6. Seminiferous tubules
  7. Lobule
  8. Septum
  9. Tunica albuginea

  A) 1

  B) 2

  C) 3

  D) 4

  E) 5

  F) 6

  G) 7

  H) 8

  I) 9

  
• • Epididymis
  • Ductus (vas) deferens
  • Urethra

  Duct system
• Path of sperm

  1. Seminiferous tubules
  2. Rete testis
  3. Epididymis
  4. Ductus (vas) deferens
  5. Urethra
• • “Sperm-forming factories”
  • Empty the sperm into the Rete testis

  Seminiferous Tubules
• • (another set of tubules) that is located to one side of the testis
  • After the rete testis, the sperm enters the first part of the duct system

  Rete testis
• Aid in the delivery of sperm to the body exterior or to the female reproductive tract

  Male Duct System
• • First part of the male duct system
  • Hugs the posterior surface of the testis
  • Highly convoluted/coiled tube about 6 meters (20 feet)
  • Provides a temporary storage site for the immature sperm
  • Sperm mature and develop the ability to swim as they travel along the epididymis (takes 20 days)
  • When a man is sexually stimulated, he ejaculates.

  Epididymis
• During ejaculation, the walls of the epididymis contract to propel sperm into the next part: the ductus (vas) deferens
• • Runs upward from the epididymis via the spermatic cord into the inguinal canal, to pelvic cavity and then arches over the superior aspect of the urinary bladder.
  • It loops medially over the ureter and descends along the posterior bladder wall.
  • The sperm travel to the ampulla (expanded terminal portion of the ductus deferens) and are emptied to the;
  • Ejaculatory duct that passes through the prostate to merge with the urethra

  Ductus (vas) deferens
• • Etymology: carrying-away vessel.
  • Runs from the epididymis through the inguinal canal and arches over the bladder.
  • Ampulla: end of the ductus deferens, empties into the ejaculatory duct.
  • Ejaculatory duct: passes through the prostate to merge with the urethra.
  • Main Function: To propel live sperm from their storage sites.

  Ductus (vas) deferens
• During ejaculation, thick layers of smooth muscles in its walls create peristaltic waves that squeeze the sperm forward (creates a trajectory)
• 1. urinary bladder
  2. urethra
  3. ureter
  4. ejaculatory duct
  5. Ductus (vas) deferens

  A) 1

  B) 2

  C) 3

  D) 4

  E) 5

  
• • Some men voluntarily take responsibility for birth control by having a vasectomy, where:
  • A small incision is made to the scrotum, then the ductus deferens is cut and tied.
  • EFFECT: Sperm no longer leave the body and later die and are phagocytized (male becomes sterile)
  • BUT, Testosterone is still produced so the man retains his sex drive and secondary sex characteristics


  The Ductus (vas) deferens: A reference point for birth control
• • Extends from the base of the urinary bladder to the tip of the penis.
  • Carries both urine and sperm but releases them in different timeframes—bawal sabay
  • Regions of the urethra include:
  • Prostatic urethra: surrounded by the prostate gland.
  • Membranous urethra: outside of the prostate to the bulb of the penis.
  • Spongy (penile) urethra: runs within the length of the penis to the external urethral orifice.

  Urethra
• Regions of urethra

  • Prostatic urethra
  • Membranous urethra
  • Spongy (penile) urethra
• If the urethra acts as a passageway for both urine and semen, can both fluids leave the body at the same time?

  No. When ejaculation happens and sperm enters the prostatic urethra, the bladder sphincter (urethral internal sphincter) closes. Because of this, urine can’t pass to the urethra. The bladder sphincter also closes to prevent semen from entering the urinary bladder.
• 1. Bladder
  2. Prostatic urethra
  3. Membranous urethra
  4. Spongy (penile) urethra

  A) 1

  B) 2

  C) 3

  D) 4

  
• Accessory Organs

  • Seminal Glands (Vesicles)
  • Prostate
  • Bulbourethral Glands
• These glands produce the bulk of semen, the sperm-containing fluid that is pushed out of the reproductive tract during ejaculation

  Accessory organs
• • Found at the base of the bladder.
  • Produces a thick, yellowish fluid:
  • Fructose (sugar)—causes thickness.
  • Vitamin C
  • Prostaglandins
  • Other substances that promote motility.
  • The duct of each seminal vesicle joins that of the ductus deferens on each side to form the ejaculatory duct.

  Seminal Glands (Vesicles)