The vagina comprises vaginal tissue and vaginal canal. The vaginal tissue consists of the vaginal mucosal folds (vaginal epithelial cells), the vaginal smooth muscle layer, and vaginal connective tissue. The contraction of the vaginal smooth muscle differs from that of skeletal muscle and is not under conscious control.
In the absence of sexual stimulation and arousal, the vagina is like a deflated, flattened balloon. The walls of the vagina may be folded together, and the vaginal cavity is not very obvious. It is not, as ordinary men and women imagine, a distinct space with "holes" or a small, undeformed steel "pipe".
The smooth muscles of the vagina have a strong ability to relax and contract. When stimulated, such as during sexual arousal, intercourse, or childbirth, the vagina expands like a balloon, regardless of whether a finger, a fist, a penis, or a child is inserted. When the stimulation disappears, the vagina contracts and returns to its natural state. The recovery time varies depending on individual constitution and age. For young women who have given birth naturally, especially those of childbearing age in China who have only one child, the vagina usually returns to its original state within three weeks to three months. However, if it is a multiple pregnancy or the fetus is too large and there is birth trauma, the recovery time may be longer or it may not return to its original state. If the mother is older, such as over 40, although she is just beginning to age, the resulting drop in estrogen levels may have already caused the vaginal walls to thin, the vaginal muscles to weaken, and the contractile ability to decrease, thus the vagina may not be able to return to its original state.
