Which layer of the vagina is composed of squamous cells?

The layer of the vagina that is composed of squamous cells is the mucosa. The mucosa is the innermost layer of the vaginal wall and features a stratified squamous epithelium, which serves several functions including protection against physical trauma and the prevention of infection. This type of epithelium is well adapted to withstand the friction and other stresses of the vaginal environment during sexual activity and childbirth.

The other layers of the vaginal wall differ in composition and function. The muscularis layer contains smooth muscle arranged in two layers, contributing to the vagina's contractility and its ability to accommodate the passage of the fetus during birth. The adventitia is the outermost layer, primarily composed of connective tissue that provides structural support to the vagina. Lastly, the endometrium is the inner lining of the uterus, not the vagina, and is involved in the menstrual cycle and pregnancy, further distinguishing it from the layers of the vaginal wall.