Male anatomy Repro

Male reproductive tract is composed of

Scrotum

Testes

Excurrent ducts

Spermatic cord

Accessory sex glands

Penis and associated muscles

Scrotum

A two lobe sac located between rear legs in most farm animals. Exception in pigs and cats. Whale, elephants and chickens have testes located in the abdominal cavities

Functions of the scrotum

Provides protection for testes

Plays a part in temperature regulation of the testes

Parts of the scrotum (skin)

-the skin is thinner than the skin on the rest if the body and has less hair. Is also heavily populated with sweat glands which provide evaporative cooling for testes

-skin has a large number of sensory nerves that regulate scrotum sweating and respiration in some animals

Parts of the scrotum (Tunica dartos)

-a smooth muscle that is responsible for size and position of the scrotum. Since a smooth muscle it does not tire and is able to maintain contraction for long periods of time

-contracts or relaxes as a result of the input from the sensory nerves in the skin in response to the temperature (heat causes it to relax moving testes away from the body increasing the length of scrotum and the surface area)(cold causes it to contract shortening testes and moving them closer to the body)

-influenced by the hormone testosterone, castrated animals lose their ability to alter the scrotum in response to heat or cold.

Parts of the scrotum 3

Scrotal Fascia

Parts of the scrotum (parietal vaginal tunic)

The serosal layer that is continuous with the peritoneum of the abdomen and lines the entire gut.

Conditions of the scrotum

-trauma (fences, stepped on)

-dermatitis (skin infection)

-hernia (the passage of intestines into the scrotum through a defective inguinal ring)

-Scrotal fat (normal fat is not supposed to be present in the scrotum in large amounts however in bulls on high levels of nutrition (bull tests) fat may accumulate in the scrotum which reduces ability to cool testes

-short scrotum bulls (scrotal circumference;bigger the more sperm can produce)

Testes

The testes are paired organs located within the scrotum

Testes functions

-spermatogenesis (the production of sperm)

-production of hormone testosterone

-production of rete fluid which is necessary for the maturation and transportation of sperm

-production of other hormones such as inhibin and estrogen

Testicular descent

In the developing fetus the testes develop in the germinal ridge (as the ovary) at the level of the 10th thoracic rib

The developing testes are retroperitoneal (under peritoneum) and are surrounded by the tunica albuginea

Attached to the caudal portion of the testes is a ligament called the gubernaculum

The other end of the gubernaculum is attached to the ventral body wall at the spot where the scrotum will develop and fuses with the peritoneum

Occurs at mid gestation in bull and ram

Occurs during late gestation in man and swine

In the stallion it occurs just prior to or after birth

Conditions associated with testicular descent

Inguinal hernia

Crytorchidism (Latin for hidden testicle) - condition where one or both testes fail to descend into scrotum. The testes may be located at the inguinal ring or deep in the abdominal cavity. Most common in horses where it is actually a genetic trait.

Parts of the testes

Testicular capsule

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