Fundamentals of Anatomy and Physiology

488

LABORATORY

The Reproductive System continued^
EXERCISE:

median body of the uterus. (In the human female,

the uterus is a single, median structure.)

The body of the uterus continues posteriorly

with the vagina, slightly larger in diameter than

the uterus, and marked from it by a slight

constriction, the cervix. The vagina lies between

the rectum and the urethra and disappears from

view into the ring of the pelvic girdle.

The Male Fetal Pig

The structures described here refer to the male; if

your specimen is a female, examine another

student’s male specimen. Refer to Figure 19 - 16.

The paired male gonads, or testes, are located

by finding the ducts that carry sperm from the

testes to the urethra. In the space bounded

ventrally by the urinary bladder, laterally by the

ureters, and dorsally by the rectum, you will see

two thin ducts that join medially and then attach to

the dorsal side of the urethra. Follow these ducts,

each a vas deferens, from their

medial junction, and note that they diverge and

loop over the ureters. Follow one vas deferens

posteriorly until it enters a small opening in the

posterior peritoneal wall. The passageway into

which this opening leads is the inguinal canal.

Each testis first develops in the peritoneal

cavity near the kidney. As the fetus matures, the

testes move posteriorly, or descend, passing

through the inguinal canal and into a pocket at the

base of the hind leg. This pocket is the scrotum.

Next carefully remove the skin at the base of one

hind leg. Just beneath the skin, you will notice a

white bulbous structure, covered with a

transparent membrane. The testis of the adult will

lie in this scrotal sac. Carefully clean away all the

surrounding tissue.

Located on or around the testis, find the

epididymis, a very tightly coiled tubule, usually

lighter in color than the testis. The coils of the

epididymis serve for temporary storage of sperm

cells. Trace the epididymis to its junction with the

vas deferens.

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W. James and Morton David by

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Figure 19- 16 The reproductive organs of a male fetal pig.