LESSON 5

CHAPTER 9

Chapter 9 describes the physiology of sexual response in both men and women. In this chapter the authors:

Learning Outcome 14

* Discuss Masters and Johnson's four stages of sexual response: excitement, plateau, orgasm, and resolution.

The basic physiological responses that occurs during the excitement, plateau, orgasm, and resolution phases of the human sexual response cycle are vasocongestion and myotonia. The first phase, excitement, involves vasocongestion and vaginal lubrication for the female and an erection for the male. Literally, vaginal lubrication occurs because of the accumulation of blood in the tissues around the vagina. Also during the excitement phase, nipple erection could occur as a result of myotonia. The plateau stage is experienced as vasocongestion reaches its peak.” Ejaculatory inevitability” is part of the male’s orgasm when ejaculation will occur whether desired or not. The resolution phase is when the body returns to an unaroused state.

Learning Outcome 15

* Discuss cognitive-physiological models, including Kaplan's triphasic model of sexual response and Wallen and Roth's cognitive model of arousal and sexual response.

The first phase in Kaplan’s model is desire, missing in Masters and Johnson’s model of sexual arousal. This phase is similar to perception of a sexual stimulus, as the first step in the Walen and Roth’s cognitive model of sexual arousal. Wallen and Roth present a “feedback loop” which is the overall process to a positive sexual response.

Erections can be produced by fantasy, purely psychological factors and tactile stimulation.

Learning Outcome 16

* Discuss hormonal and neural control of sexual behavior, including the role of the brain and the spinal cord in sexual response, and the function of pheromones.

At this point in our knowledge of the brain and sexuality, the most important influences On human sexual responses are based on a set of brain structures called the limbic system and research on brain control of the sexual response has focused on this system. It appears that the family of hormones related to sexual desire in both the female and the male is androgens. The “organizing effect” of hormones can be seen in the masculinizing of sexual behavior of female animals who have been administered testosterone prenatally.

Based on scientific research and interviews with groups of women to date, stimulating the mid-front vaginal wall may increase sexual pleasure; this area is known as the G-spot. However much of what has been written about the G-spot is contradictory

According to most studies done on individuals who have had a spinal cord injury, many men are still able to have erections yet often males with spinal cord injury cannot ejaculate. One reason why pheromones may be important is that the brain centers for sex are so close to the olfactory centers. Human pheromones can influence the ovulation of women if they are exposed to pheromones of women who were almost ready to ovulate and are for the most part below the observable level of direct smell. Is this important? Ask the perfume industry.

DISCUSSION QUESTION:

LESSON FIVE/CHAPTER NINE

For posting on discussion board.

Note: plan on using quotations (few) and paraphrasing from the text as well as your own observations. Respond to two other students (explain your responses). Be sure that you post three times separately to receive full credit for your responses.

What are the “issues” involved when we distinguish between a vaginal and a clitoral orgasm? Explain.