The testes are the paired male reproductive
glands. In humans these are found outside the abdominal cavity in
the pouch of the scrotum. The testes contain the seminiferous tubules
where the sperm are made. There are about 500 seminiferous tubules
in each testis. Each measures about 80cm in length, but has a diameter
of only 0.2mm.
The epididymis is a long convoluted tubule which
sits above each testis in the scrotum. It not only stores sperm,
but also helps them to mature. Sperm leaving the seminiferous tubules
are incapable of fertilising an egg, but those leaving the epididymis
are ready for action.
The vas deferens is the muscular tube which conducts
the matured sperm from the epididymis towards the penis. Its muscular
wall plays an important role in propelling the sperm forwards during
ejaculation.
The seminal vesicles are blind-ending sacs which
contribute approximately 70% of the seminal fluid. Their exit ducts
join with the vas deferens to form the ejaculatory ducts near the
prostate gland.
The prostate gland is normally about the size
of a walnut and is located below the bladder. It also contributes
to the seminal fluid.
The penis is composed of loose spongy erectile
tissue. When this tissue is distended with blood, it causes the
penis to become erect and allows the sperm to be deposited in the
female genital tract near the uterine cervix.
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