micturition2

Accessory Excretory Structures Balance contd/….

Urethra

Thin walled tube of smooth muscle lined internally with mucosa. It transports the urine from the bladder to the outside. In the female the urethra is around 4cm in length. In the male it is about 20cm in length from the bladder to the tip of the penis.

The male urethra passes through three different regions:

1.	The *prostatic portion* passes through the prostate gland and is joined by the ejaculatory duct. Thus distal to this the male urethra serves both excretory as well as reproductive functions.
2.	The *membranous portion* is a short segement passing through the pelvic diaphragm.
3.	The *penile portion* is the longest portion and extends the length of the penis. It is joined by ducts from the *bulbourethral glands* and *seminal vesicles*. These two structures together with the prostate gland, secrete fluids into the semen during ejaculation.