male reproductive system

• Penis : Organ for passing urine and transferring sperm to female 
• Erectile tissue : Connective tissue very rich in blood supply. it contains a large number of sponge-like spaces which fills with blood during sexual arousal, causing the penis to enlarge, stiffen and become erect 
• Foreskin : covers end of penis 
• testes : where sperm is produced
• testes are divided internally into 200 to 300 lobules each filled with fine tubes called seminiferous tubules. these tubules are lined with cells that produce male gametes. they join to form short straight tubules that eventually join into ducts which leave testis and enter the epididymis. clusters of interstitial cells between seminiferous tubules secrete testosterone 
• Scrotum : Holds and supports testes outside of the body
• Development of sperm requires a temperature of about 2°C below body temperature, the scrotum holds the testes outside the body. contraction of smooth muscles fibres in wall of scrotum can move tests closer to the body where it is hotter if needed.
• scrotum is a skin-covered pouch which appears to be a single pouch of skin, but is divided internally into two sacs 
• Epididymis : Sperm is stored for up to a month while they mature 
• Epididymis is a highly folded tubule around 5-6m long which fits against the rear surface of each testis 
• Vas deferens : Carries sperm away from testes
• the vas deferens extends upward from testis, passes into abdominal cavity, crosses upper surface of bladder and returns downwards, looping behind bladder. Under bladder, two vas deferentia join the urethra
• Urethra : Duct for transporting urine and sperm to the exterior of the body. it carries sperm and semen through penis to a slit-like opening at the tip, running from the bladder through the penis to the outside 
• For transfer into female’s body and to reach egg, the sperm must be in a liquid. Semen (seminal fluid) nourishes and aids the transport of sperm and is made up of secretions from three glands :

  • seminal vesicle
  • prostate gland
  • bulbo-urethral glands
• Seminal vesicle : Secrete thick fluid that is rich in sugars and makes up 60% of volume of semen 
• seminal vesicle are a pair of pouch-like organs around 5cm in length. located behind urinary bladder 
• Prostate gland : Secretes a thin, milky, alkaline fluid 
• Prostate gland is located where vas deferentia join urethra. it is a single gland shaped like a doughnut surround the urethra just below the bladder 
• Bulbo-urethral glands : Secrete clear mucus which acts as a lubricant. much of it precedes emission of seminal fluid, with only a small amount included in semen. the secretion is carried to urethra by a duct from each gland
• Bulbo-urethral glands are two small, yellow glands, each about the size of a pea. they are located beneath the prostate glands on either side of urethra 
• parts of male reproductive system

  A) penis

  B) vas deferens

  C) prostate gland

  D) urethra

  E) erectile tissue

  F) testis

  G) epididymis

  H) bulbo-urethral gland

  I) seminal vesicle

  J) scrotum

  K) foreskin