Reviewed by: Dr Amanda Hordern, PhD, and Doreen Akkerman, AM
On this page: Men's sex organs | Women's sex organs
Excitement, orgasm and resolution are three important sexual stages. Underlying these is the interest you have in sex (libido).
Excitement or arousal is when you begin to feel ready for sex. You may become aroused by seeing someone you like, having a sexual thought or fantasy, or having your genitals or other sensitive areas kissed, touched or stroked. Blood pressure and heart rate increase, the chest becomes more sensitive and blood is sent to the genital area. In both men and women the nipples may harden. In men, the penis becomes erect and sensitive. In women, the vagina becomes moist and increases in depth and width.
Orgasm is the peak of sexual response. The nervous system creates the intense pleasure you experience in the genital area. This causes the muscles in the area to contract in rhythm, sending waves of feeling through the body. In men, ejaculation occurs when the muscles around the base of the penis begin to squeeze in rhythm, pushing the semen through the urethra and out of the penis. In women, clitoral stimulation causes the sudden release of muscular tension which sends waves of pleasure through the genital area and sometimes over the entire body. Some women also experience a small ejaculation.
Resolution is when breathing, heart rate and blood pressure return to normal. Men usually cannot be sexually aroused again for a while. The length of time between having one erection and being able to have another usually increases with age. Women are able to have multiple orgasms but generally feel relaxed and satisfied after one.
The strength of men's erections may decrease with age. Women may experience increased dryness in their vaginas as they age, even when they feel aroused or excited. See below for some practical tips.
A man's sex organs (genitals) are mostly outside his body (see diagram).
The end of the penis is covered by the foreskin, if it hasn't been removed by circumcision. The ridge on the underside of the head of the penis, called the frenulum, is usually a man's most sensitive part. At the very end of the penis is a slit opening to the urethra, through which semen and urine pass.
At the base of the penis is a pouch of skin called the scrotum. It contains the testes. These produce sperm and store it. They also produce the male sex hormone, testosterone.
The other parts of the man's reproductive system lie inside his body. The prostate gland is deep in the pelvis and surrounds the urethra as it leaves the bladder. The prostate gland produces fluids that contribute to the semen and helps create the intense sensations a man experiences when he has an orgasm.
A man's chest and nipples can be sensitive and his body may have other erogenous or highly pleasurable zones.
A woman's sex organs are mostly inside her body. Outside the body are the outer lips of the vagina, or labia majora (see diagram). When parted, these show the thinner, inner lips, the labia minora. These join at the top to cover the external part of the clitoris with a fatty hood. The major part of the clitoris lies inside the body. The clitoris is usually sensitive to touch. The external organs are usually called the vulva.
Beneath this is the urethra, for passing urine. Further back is the vagina. Beyond that is an area of skin called the perineum and beyond that is the anus.
Inside a woman's body is the uterus (womb), the cervix and the ovaries.
Other sexual areas include the breasts and nipples, which harden when sexually aroused, and there may be other erogenous zones that respond to direct touch.
