The vagina is a muscular tube that connects the external genitals to the uterus. It serves multiple functions, including the passage for menstrual fluid, the birth canal during childbirth, and the receptacle for the penis during sexual intercourse. The inner walls of the vagina are elastic and can expand and contract. One important part of the vagina is the vaginal canal, which is lined with mucous membranes that help maintain moisture and protect against infections. The vulva, which includes the external parts of the female genitalia, surrounds the vaginal opening and plays a role in sexual arousal and protection.