Urethra


Urethra


Reproductive System :
Male Reproductive Organs or Genitalia

     The urethra is the last part of the man reproductive system. It comes from the urinary bladder and opens on the external hole of the penis by going through the prostate gland. It expels out urine at the time of urination and semen at the time of ejaculation from the body. The process of urination and ejaculation cannot be done at one time because just before the ejaculation internal contraction closes the hole of urinary bladder. This contraction is not loose until the ejaculation. Neither a person can pass urine nor the semen returns back into the urinary bladder if the internal contraction is closed.

     There are three parts of man’s urethra-the portion of urethra which starts from the base of urinary bladder and reaches to its end by passing through the prostate gland is called prostatic portion. Here it gets the secretions from the small ducts and two ejaculatory ducts. The portion from the prostate gland to the external urinary contracting muscles is called membranous portion. The last penile portion of the urethra is till the external hole of urethra from the complete spongy portion of the inners side of the penis from where the urine of semen comes out from the penis. There is a lining of mucous membrane on the wall of urethra and there is a thick layer of smooth muscle which is contracted involuntarily. There are urethral glands inside the wall which excrete mucus into the urethral canal.