Vagina

The vagina is a female’s copulatory organ and also serves as the urination organ. This thin-walled tube is highly elastic and can expand considerably during the expulsion of the foetus; hence, it is also called the birth canal.

Histological Features The vagina consists of mucosa, muscularis and serosa layer. The mucosal epithelium varies considerably in different regions. It is columnar and secretary in nature near the cervix becomes stratified squamous towards the posterior vagina. Some touch and pressure­sensitive chemotactic receptors are present in the vagina, which generates sexual stimulation and mucous secretion in response to coitus.

Function Vaginal is the copulatory organ where the semen deposits. During the natural service, the semen is deposited in the anterior vagina in most ruminants. The spermatozoa are stored in a vaginal pouch during the non-breeding season in bats. The vagina acts as an excretory duct for cervical, uterine and oviductal secretions. The vaginal environment protects the upper reproductive tract from external pathogens.

21.6.1 Suburethral Diverticulum

The urinary bladder is opened at the floor of the vagina in the form of a blind sac called the suburethral diverticulum. It is prominent in cow and sow and short and broad in mare. The suburethral diverticulum has two fossae in bitch. The diver­ticulum guides during catheterisation but must be avoided during intrauterine infusion and artificial insemination; oth­erwise leads to injury.

21.7