The Male Reproductive System(1)

The Male Reproductive System(1) - Fundamentals of animal...

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Fundamentals of animal reproduction The Male Reproductive System Testes The testes are the primary organs of reproduction in males, just as ovaries are primary organs of reproduction in females. Testes are considered primary because they produce male gametes (spermatozoa) and male sex hormones (androgens).Testes differ from ovaries in that all potential gametes are not present at birth. Germ cells, located in the seminiferous tubules, undergo continual cell divisions, forming new spermatozoa throughout the normal reproductive life of the male. Testes also differ from ovaries in that they do not remain in the body cavity. They descend from their site of origin, near the kidneys, down through the inguinal into the scrotum. Descent of the testes occurs because of an apparent shortening of the gubernaculum, a ligament extending from the inguinal region and attaching to the tail the epididymis. This apparent shortening occurs because the gubernaculum does not grow as rapidly as the body wall. The testes are drawn closer to the inguinal canals and intra-abdominal pressure adis passage of the testes through the inguinal canals into the scrotum. Both gonadotropic of hormones and androgens regulate descent of the testes.This descent is completed in the fetus by midpregnancy in cattle and just before birth in horses. In some cases one or both testes fail to descend due to a defect in development. If neither descends, the animal is termed a bilateral crytorchid. Bilateral cryptochids are sterile. If only one testis descends he is a unilateral crytorchid. The unilateral cyptochid is usually fertile due to the descended testis. The cyptochid condition can be corrected by surgery, but this is not recommended for farm animals. The condition can be inherited; therefore, surgical correction would result in the perpetuation of an undesirable trait. Prepared by Tshewang Dorji 1
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Fundamentals of animal reproduction Prepared by Tshewang Dorji 2 Diagram of the reproductive system of the (a) bull; (b) ram; (c) boar; and (d) stallion.
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Fundamentals of animal reproduction Functional Morphology The testis of the bull is 10 to 13 cm long, 5 to 6.5 cm wide and weighs 300 to 400 gm. The testis is of similar size in boars, but is smaller in rams, bucks (goats), and stallions. In all species testes are covered with the tunica vaginalis, a serous tissue, which is an extension of the peritoneum. This serous coat is obtained as the testes descend into the scrotum and is attached along the line of the epididymis. The outer layer of the testes, the t unica albuginea testis, is a thin white membrane of elastic connective tissue. Numerous blood vessels are visible just under its surface. Beneath the tunica albuginea testis is the parenchyma , the functional layer of the testes. The parenchyma has a yellowish color and is divided into segments by incomplete septa of connective tissue. Located within these segments of parenchyma tissue are the seminiferous tubules. Seminiferous tubules are formed from primary sex cords. They contain germ cells
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This note was uploaded on 03/14/2012 for the course TEHRN 122 taught by Professor Siamaksarabi during the Spring '12 term at Adams State University.

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The Male Reproductive System(1) - Fundamentals of animal...

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