Physiology of Sex

Better Sex Guide, feature 3 - By Better Sex on Friday, April 30, 2010 - 14:01

Tip 1: The Human Sex Response

Tip 2: The Sex Cycle

Tip 3: Endorphins

Tip 4: Female Ejaculation

Tip 5: Semen Anatomy

Tip 6: How Much Is Too Much?

Tip 7: Vaginismus

Tip 8: The Purpose of Pubic Hair

Tip 9: Body Language: The Eyes

Tip 10: Timing and Orgasm

The Human Sex Response

When we become aroused during a sexual encounter, our bodies go through many physical changes. The pupils of the eyes dilate; the lips of the mouth darken, the nipples become erect. For women, the clitoris swells and becomes hard and exposed; for men, the same happens to their penis. With increased excitement, the skin becomes flushed -- also known as the “sex flush” -- and it begins to sweat. In women, the labia, clitoris, vagina and pelvic organs enlarge, much the same way as the aroused penis enlarges. There is a plateau of excitement which can hold for several minutes before you are about to orgasm, depending on your personal sex cycle. Everyone has a similar sex cycle, but there is much variation within it between individuals.

The Sex Cycle

As humans, our cycles of sexual response can be divided into four separate phases: excitement phase, plateau phase, orgasmic phase, and the resolution phase. The excitement phase develops from any source of physical or psychological stimulation. The stimulation level is important establishing sufficient increments of sexual tension, which will continue the cycle. If the stimulation continues at the appropriate level for person, the intensity of response usually increases rapidly. In the plateau phase sexual tensions are intensified and reach the extreme level from which the man or woman may move to orgasm. The length of this phase has a lot to do with what the stimulation level is, combined with the person’s individual sex drive. The orgasmic phase is limited to those few seconds during which the physical build- from received sexual stimuli are released. The resolution phase is basically a reverse of these physical and psychological phases, resulting in a non-stimulated state.

Endorphins

When we orgasm during sex, endorphins are released into our spinal fluid, carrying feelings of elation and calm throughout our bodies. Endorphins are hormone-like substances that are naturally formed within the body to relieve pain. Endorphins are also considered to be involved in controlling our body's response to stress, regulating contractions of the intestinal wall, and determining mood.

Female Ejaculation

Can women ejaculate when they orgasm? Technically, yes. But the fluid is not the same as in male ejaculation. Some say that female ejaculate is nothing more than built-up moisture which is expelled from the vaginal opening during the force of orgasmic muscular contraction. Others believe that female ejaculation is caused by a release of fluid from the Skene's glands, which are located inside the urethra. The Skene’s gland is similar to the male prostate gland. It produces a fluid that is similar to the chemical composition of the prostatic fluid that makes up the majority of semen. Some women may produce greater amounts of fluid from these glands than others, which explains why some women seem to expel more fluid during an orgasm than others.

Semen Anatomy

Ever wonder what semen is actually made of? Each sperm is made up of three parts, the head, the mid-piece, and the tail. Inside the head are all the chromosomes of genetic material (DNA). The outside of the head is covered with enzymes that are needed for the penetration and fertilization of an ovum. The midpiece is essentially the engine of the unit, providing energy for the locomotion of the tail, which helps the sperm swim. Semen contains small amounts of more than thirty elements, including fructose, ascorbic acid, cholesterol, creatine, citric acid, lactic acid, nitrogen, vitamin B12, and various salts and enzymes. The rest of what a man ejaculates is made up of mainly of water, sugar, protein, vitamin C, zinc, and prostaglandins.

How Much Is Too Much?

What is a healthy sex drive? In other words, how much sex should a “normal” adult have? The answer is as broad as the spectrum of personalities that exist. Some are driven to sexual activity several times a week or perhaps even more than once a day, while others are entirely satisfied to have sex once a month or even less often. The need for sex varies, based on circumstance as well as physical and mental health. There is no solid agreement concerning what constitutes an abnormally low or abnormally high sex drive. Of course, tensions can arise in relationships where couples don’t have similar drives. Communication between couples can assist in fixing this problem, although some do seek the help of a sex therapist to find ways of remedying an unbalanced sex life.

Vaginismus

Most women know that strengthening the pubococcygeal (PC) muscles can benefit not only your sexual health but can even prevent problems of incontinence. However, some women suffer from a PC muscle disorder called Vaginismus. This disorder causes an involuntary contraction of these muscles surrounding the entrance to the vagina, making penetration impossible and or painful. Normally, the vaginal sphincter keeps the vagina closed until the need to expand -- for sexual intercourse, child birth, medical exams, etc. When the vagina is unable to relax, the sphincter goes into spasm, which results in the tightening of the vagina. The treatment of Vaginismus is usually a therapy program that includes vaginal dilation exercises using a progression of plastic dilators. The treatment can also include moving toward more intimate contact, eventually resulting in painless intercourse.

The Purpose of Pubic Hair

What is the purpose of pubic hair? In essence, it functions biologically as an aid for sexual attraction. Pubic hair sends out distinct scents (pheromones) from the genitals' scent glands that both genders find sexually stimulating. We send pheromones out by a number of methods: tears, saliva, and perspiration. Human odor plays a vital role in human sexuality and physical attraction. One of our most primal instincts is to act on what we smell, even if we are unaware of it. Sometimes you are drawn to someone and can’t be sure of why. Oftentimes it is the intermingling of your pheromones that is causing the attraction.

Body Language: The Eyes

If you want to know if someone if flirting with you, take note of how s/he is looking at you. When we flirt, we look in a triangle pattern: eyes, nose and mouth, and lower to other parts of the body, generally in a progressive manner. The more intense the flirting, the more intensely someone will look at you from eye to eye, and s/he will spend more time looking at your mouth. In fact, if someone is watching your mouth while you're talking to them, s/he could be imagining what it would be like to kiss you. In generally, if someone is turned on by what s/he sees when looking at you, his or her pupil size will increase, as will the rate at which s/he blinks.

Timing and Orgasm

Is there a standard for how quickly a person should orgasm? Why do some people reach orgasm more quickly than others? Many behavioral programs exist that can teach men who ejaculate rapidly to delay reaching orgasm. There are still others and that can help those with inhibited ejaculation bring about orgasm more easily. Women can also learn strategies to help them become aroused and orgasm more easily – or, in some cases, at all. As yet, there is no standard of time which is considered to be “correct” for how long it takes to move from arousal to orgasm. Considering the uniqueness of individual tastes and sex drives, it’s nearly impossible to calculate such a time frame. Broadly speaking, as long as the sexual experience is satisfying to you and your partner, any time is the right time to orgasm.