Page 69 - 86 human physiology part-2

Chapter 15

Ejaculatory Ducts

There are two ejaculatory ducts. Each receives sperm from the ductus deferens and the secretions
of the seminal vesicle on its own side. Both ejaculatory ducts empty into the single urethra.

Prostate Gland

The prostate gland is a muscular gland that surrounds the first inch of the urethra as it emerges
from the bladder. The smooth muscle of the prostate gland contracts during ejaculation to contribute to
the expulsion of semen from the urethra.

Bulbourethral Glands

The bulbourethral glands also called Cowper's glands are located below the prostate gland and
empty into the urethra. The alkalinity of seminal fluid helps neutralize the acidic vaginal pH and
permits sperm mobility in what might otherwise be an unfavorable environment.

Penis

The penis is an external genital organ. The distal end of the penis is called the glans penis and is
covered with a fold of skin called the prepuce or foreskin. Within the penis are masses of erectile
tissue. Each consists of a framework of smooth muscle and connective tissue that contains blood
sinuses, which are large, irregular vascular channels.

Urethra

The urethra, which is the last part of the urinary tract, traverses the corpus spongiosum and its
opening, known as the meatus, lies on the tip of the glans penis. It is both a passage for urine and for
the ejaculation of semen.

Overview of Male Reproductive System Structure and Function

STRUCTURE LOCATION & DESCRIPTION FUNCTION

Secretion of gelatinous seminal fluid called pre-
Pea sized organs posterior to the ejaculate. This fluid helps to lubricate the
Bulbourethral prostate on either side of the urethra for spermatozoa to pass through, and to
glands (2)
urethra. help flush out any residual urine or foreign
matter. (< 1% of semen)
Cells of Leydig Adjacent to the seminiferous Responsible for production of testosterone.
(Interstitial cells tubules in the testicle. Closely related to nerves.
of Leydig)
Cremaster muscle Covers the testes. Raises and lowers scrotum to help regulate
temperature and promote spermatogenesis.

284 | Human Physiology