Page 461 - Anatomy and Physiology of Farm Animals, 8th Edition

446 / Anatomy and Physiology of Farm Animals

and relatively hairless (except in some form the scrotal septum, which divides
the scrotum into two compartments, one
breeds of sheep, in which fleece covers the
VetBooks.ir scrotum). A layer of fibroelastic tissue for each testis. Deep to the tunica dartos
are several layers of fascia, which are not
mixed with smooth muscle fibers, called
the tunica dartos, lies immediately under easily separated. The internal abdominal
the skin (Fig. 24‐6). During exposure to oblique muscle contributes a slip of muscle
cold temperatures the muscle fibers of the that lies superficial the spermatic cord.
tunica dartos contract and assist in holding This is the cremaster muscle, which also
the testes against the abdominal wall. The assists with drawing the testicle closer to
tunica dartos sends a fibrous sheet into the the body wall when ambient temperatures
median plane between the two testes to are low, or as a protective reflex.

(A)

Ductus deferens
Cremaster muscle Skin and tunic dartos
Spermatic fascia
Epididymis

Visceral and
Testis Parietal layers of
vaginal tunic

(B) Deep inguinal ring
Body wall
Inguinal canal
Superficial inguinal ring

Spermatic cord
Parietal layer
of
Pampiniform plexus vaginal tunic

Mesorchium

Visceral layer
Tunic dartos of
vaginal tunic
Skin of the scrotum

Figure 24-6. Relation of testes to peritoneal investments. (A) Cross‐section image demonstrating the
relationship of the tests in the scrotum with various layers of peritoneum. (B) The spermatic cord,
comprising ductus deferens, blood vessels, and nerves, passes through the abdominal body wall via the
inguinal canal. The spermatic cord, the inguinal canal, and the testes are lined with extensions of the peri-
toneum. Source: Evans and de Lahunta, 2012. Reproduced with permission of Elsevier.