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The Male Reproductive System

sperm cells to swim through, and preventing their diffusion out of
the semen. Contributes to the cohesive jelly-like texture of
semen.), pre-ejaculate, sialic acid
A 1992 World Health Organization report described normal human semen as having a volume of 2
ml or greater, pH of 7.2 to 8.0, sperm concentration of 20x106 spermatozoa/ml or more, sperm count of
40x106 spermatozoa per ejaculate or more and motility of 50% or more with forward progression
(categories a and b) of 25% or more with rapid progression (category a) within 60 minutes of
ejaculation.[2]

Functions

Hormone Regulation

Hormones which control reproduction in males are:

Gonadotropin-Releasing Hormone (GnRH):

• The hypothalamus secretes this hormone into the pituitary gland in the brain.
• There are two gonadotropic hormones, FSH and LH.

Luteinizing Hormone (LH):

• The pituitary gland secretes this hormone after receiving a GnRH signal from the
hypothalamus.
• LH stimulates Leydig cells, in the testes, telling them to produce testosterone.

Follicle-Stimulating Hormone (FSH):

• The pituitary gland also secretes this hormone.
• Testosterone helps FSH run through the bloodstream to make Sertoli cells, located in the
seminiferous tubules of the testes, to make immature sperm to mature sperm.

Testosterone:

• Also know as "the male hormone" and "androgen".
• Testosterone is vital for the production of sperm.

Erection

The erection of the penis is its enlarged and firm state. It depends on a complex interaction of
psychological, neural, vascular and endocrine factors. The term is also applied to the process that leads
to this state.

A penile erection occurs when two tubular structures that run the length of the penis, the corpora
cavernosa, become engorged with venous blood. This is a result of parasympathetic nerve induced

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