Write a note on male accessory glands.

The male accessory glands include paired seminal vesicles, a prostate and paired bulbourethral glands. These glands secrete semen.

Seminal vesicle : Seminal vesicles are located below the bladder within the pelvis. It produces $60 \%$ fluid of semen. Its yellowish and viseous secretion is enriched with sugar, vitamin $\mathrm{C}$ and other substances which nourishes sperm cells. Each duct of seminal vesicle unite with vas deferens and forms an ejaculatory duct so sperms enter into urine genital tract along with seminal vesicle fluid.

Prostate gland : Prostate gland is located in posterior part of urinary bladder. The secretion of prostate gland is like milk. It activates sperms. It enters into urine genital tract by many small ducts.

Bulbourethral gland : These glands are located beneath the prostate gland in the posterior part of urine genital tract. It secretes basic (alkaline) liquid like prostate gland.

Constitution of semen : Semen is white like milk and sticky mixture of sperms and secretion of accessory glands. The relative alkality of semen (pH $7.2$ TO $7.6$) helps to neutralize acidic atmosphere of vagina. It protects fragile sperms and increases its motility. In each ejection size of volume of semen is $3$ to $4 \mathrm{ml}$.