Sexual thoughts, the sight of a partner’s body, and foreplay all contribute to sexual arousal. Excitement makes breathing quicken, heart rate increase, and blood pressure rise. In a male, the penis becomes firm and erect. In a female, the labia and clitoris swell, the vagina lengthens and becomes lubricated, and the breasts enlarge. The time taken for sexual arousal varies between men and women.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.