Male Reproductive System

male reproductive system3

The Male Reproductive System is consists of:

  • testes
  • ducts: epididymis, vas deferens, urethra
  • accessory glands: seminal vesicles, prostate glands, Cowper’s gland
  • supporting structures: scrotum, penis

External Structures:

  1. Penis – comprised of 3 columns of erectile tissues (2 corpus cavernosa on the sides of the shaft; 1 corpus spongiosum around the urethra).
    • Consists of the Shaft and the Glans Penis
      • Shaft – contains the urethra which is the passageway for urine and semen
      • Glans – is highly sensitive (well supplied with sensory receptors) and is located at the dismal end of the penis. At the tip of the glans is the opening to the urethra, called urethral meatus. It is covered by a fold of skin, Prepuce/foreskin that is often removed during circumcision.
    • During sexual stimulation, the penis may become engorged with blood, enlarged, hardened and erect.
  2. Scrotum – rugated skin-covered muscular pouch/sac suspended from the perineum. It contains the testes, epididymis and the lower portion of the spermatic cord. It is divided into left and right internal compartments by a septum. Beneath the skin is a layer of loose connective tissue and a layer of smooth muscle, called Dartos muscle. In cold temperature, the dartos muscle contracts, causing the skin of the scrotum to become firm and wrinkled and reducing the size of the scrotum. An extension of the abdominal muscles into the scrotum the Cremaster muscles contract pulling the testes nearer to the body to raise it’s temperature. During warm weather or exercise, the dartos and cremaster muscles relax, the skin of the scrotum becomes loose and thin, and the testes descend away from the body to lower their temperature. If the testes become too warm or too cold, normal sperm cell development does not occur.

male reproductive system2

Internal Structures:

  1. Testes – considered the male gonads are 2 oval organs, 4-5 cm long within the scrotum. Each testes is encased by a protective white fibrous capsule and comprises a number of lobules, each lobule containing interstitial cells/Leydig’s cell and seminiferous tubule. Seminiferous tubules produce spermatozoa while the Leydig cells are responsible for the production of testosterone.
  2. Epididymis – a tightly coiled tube about 20 feet long responsible for the conduction of sperm from the testes to vas deferens. It is where some sperm stored and a part of the fluid that surrounds the sperm (semen/seminal fluid) is produced by cells lining the epididymis.
  3. Vas deferens/Ductus deferens – a tube surrounded by arteries and veins and protected by a thick fibrous coating. It carries sperm from epididymis into the pelvic cavity. The blood vessels and the vas deferens together are refererred to as a spermatic cord.
  4. Seminal vesicle 2 convoluted pouches that lie along the lower portion of the bladder and empty into urethra by way of ejaculatory ducts. These glands secrete a viscous portion of the semen which has a high content of the basic sugar and is alkaline in pH.
  5. Prostate Gland – lies just below the bladder. It secretes a thin alkaline fluid that when added to the secretion from the seminal vesicle and sperm from the epididymis further protects the sperm from being immobilized by natural low pH (acidic) level of the urethra due to passage of urine through the same lumen.
  6. Urethra – hollow tube leading from the base of bladder, passing through the prostate gland, continues to the outside through the shaft and glans penis.
  7. Cowper’s glands – lie beside the prostate gland and by short ducts empty into the urethra. They secrete an alkaline fluid that helps counteract the acid secretion of the urethra and ensures safe passage of spermatozoa.

Functions of Male Reproductive Organs

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