Accessory Glands in Animial Reproductive System: Functions and Significance

Accessory Glands in Animial Reproductive System: Functions and Significance

Reproductive accessory glands, also known as accessory sex glands, are organs that support the process of reproduction in animals. These glands are separate from the main reproductive tract and play distinct roles in males and females. In this article, we will explore the details of both male and female accessory glands, their functions, and their significance in the reproductive system.

 

Accessory Glands of the Male Reproductive System:

The male reproductive system includes various accessory sex glands that are outgrowths of the urethra or the spermatic duct. The major male accessory glands are the bulbourethral glands, seminal vesicles, prostate gland, and ampullary glands. While these glands are present in many mammals, their presence may vary among different species.

1. Prostate Gland: The prostate gland is a firm and dense structure located below the urinary bladder. It surrounds the urethra as it exits the bladder. The prostate gland secretes thin, alkaline secretions that enhance sperm motility. These secretions are milky in color and contain substances that support the survival and movement of sperm. The prostate gland is widely distributed among males, except in some marsupials and carnivores.

2. Seminal Vesicles: The seminal vesicles are paired, elongated, and coiled sac-like structures located posteriorly to the urinary bladder. Each seminal vesicle has a short duct that combines with the ampulla of the ductus deferens, forming an ejaculatory duct. This duct empties into the urethra or the spermatic duct. The seminal vesicles produce a fluid rich in fructose, which serves as an energy source for sperm. The fluid also contains prostaglandins that contribute to sperm motility and viability. Seminal vesicles are absent in certain mammals, such as monotremes, marsupials, cetaceans, carnivores, some primates, insectivores, and rabbits.

3. Bulbourethral Glands: The bulbourethral glands, also known as Cowper's glands, are paired glands located near the base of the penis. These small glands secrete an alkaline, mucus-like fluid in response to sexual stimulation. The fluid neutralizes the acidic residues of urine in the urethra and lubricates the penis tip during intercourse. While most species have a single pair of bulbourethral glands, marsupials may have up to three pairs. The presence of these glands varies among different animals.

4. Ampullary Glands: Ampullary glands are present in some species along with the seminal vesicles. They are responsible for producing additional secretions that contribute to semen composition. However, not all animals have ampullary glands, and their presence varies among species.

 

Seminal Fluid: Seminal fluid, also known as semen, is a mixture of secretions from the male accessory glands and sperm cells. It is alkaline in nature. Seminal vesicle secretions constitute about 60 percent of the semen volume, while prostate gland secretions make up the remaining volume. The fluid from the bulbourethral glands and sperm cells constitute only a small percentage of the overall volume. The volume of semen and sperm count can vary among individuals, but a sufficient number of sperm cells are needed for successful fertilization.

 

Accessory Glands of the Female Reproductive System:

The female reproductive system has fewer accessory glands compared to males. The major accessory glands in the female reproductive system include Bartholin's glands, prostates, and various mucosal glands.

1. Bartholin's Glands: Bartholin's glands, also known as bulbo vestibular glands, are a pair of glands present in females. They are homologous to the bulbourethral glands in males. In mammals, these glands usually empty into the urinogenital sinus. In primates, they open into a shallow vestibule near the vaginal opening.

2. Prostates: In some female embryos, prostates develop as buds from the urethra, but they often remain partially developed. Complete development of the prostate is observed in certain rodents, chiropterans (bats), and lagomorphs (rabbits and hares). The function of the prostate in females is not well understood.

3. Labial, Urethral, and Preputial Glands: The female reproductive system also contains various mucosal glands, including labial, urethral, and preputial glands. These glands secrete mucus that aids in lubrication and nourishment of the embryos before implantation. The cervical uterine glands also secrete mucus, which helps lubricate the vagina.

 

In conclusion, accessory glands play vital roles in the reproductive system of both males and females. Male accessory glands, including the prostate gland, seminal vesicles, bulbourethral glands, and ampullary glands, contribute to the composition and functionality of semen. Female accessory glands, such as Bartholin's glands, prostates, and mucosal glands, have various functions related to lubrication and nourishment. Understanding the functions and characteristics of these glands enhances our knowledge of reproductive processes in animals.