Accessory Sex Glands - Anatomy & Physiology

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Introduction

Accessory sex glands are all found along the length of the pelvic urethra. They produce secretions containing lots of different components many of which can be found also the blood. One of the most important substances is fructose which provides an energy source for sperm. Along with providing nutrition for spermatozoa sex gland secretions facilitate movement of the sperm as well as providing a physiological buffer against the acidic environment of the female tract. There is species variation in which glands are present:

• Bull and stallion – Ampullary, vesicular, prostate and bulbourethral glands
• Boar – Vesicular, prostate and bulbourethral glands
• Tom Cat – Ampullary, prostate and bulbourethral glands
• Dog – prostate glands only

Development and function of the accessory sex glands is androgen dependant. This is highlighted by individuals producing little or no androgens having small accessory sex glands.

Bulbourethral Glands

• Paired glands
• Found near the ischial arch either side of the urethra
• These are very dense glands containing a lot of fibrous connective tissue.
• These glands are very large in the boar and absent in the dog.

Prostate Gland

• Singular gland
• Found at the junction between the bladder and the urethra.
• Huge variation between species with regard to size and shape; heart shaped in the boar, h-shaped in the stallion and consists of four lobes in the tom.
• It can consist of two different parts:
  • Corpus prostate – a compact body of tissue found external to the urethra. The stallion only possesses this part of the prostate gland and in the dog & tom cat the corpus is very large and globular. This part is absent in the Ram and other small ruminants. The bull possesses both corpus and disseminate parts of the gland.
  • Disseminate prostate – a diffuse tissue found within the wall of the pelvic urethra. The prostate gland in the ram is entirely disseminate and in the boar makes up the major part of the gland. This part of the gland is absent in the stallion and vestigial in the dog and tom cat.

Ampullary Glands

• Paired glands
• Found lying on the dorsal neck of the bladder. They develop due to a glandular enlargement within the wall of the ductus deferens as it crosses the dorsal surface of the bladder.
• The glands are connected to the urethra via the ejaculatory duct.

Vesicular Glands

• Paired glands
• Found dorsocranial to the pelvic urethra
• In the boar and bull these glands produce a large proportion of the overall volume of ejaculate.
• In the bull and boar these glands have irregular surface but in the stallion they are smooth.