1. Sexual Arousal and Response

2. Factors influencing arousal and response
Hormones
Brain’s capacity to create images and fantasies
Emotions
Sensory processes
Level of intimacy between two people
Sexual expression is influenced by interplay of:
Social, emotional, and cognitive factors
Brain neurons
Spinal reflexes

3. Role of Hormones in Sexual behavior
Steroids: the sex hormones and hormones of the adrenal cortex
Both sexes produce male sex hormones (androgens) and female sex hormones (estrogens)
Androgens: for men, 95% are produced by the testes; for women, the ovaries and adrenal glands produce androgens in equal amounts
The dominant androgen is testosterone and men produce about 20 to 40 times more testosterone than women
Estrogens are produced by the ovaries by females and in small amounts by the testes for males.

4. hormones
Neuropeptide hormones are the chemicals of emotion produced in the brain. They influence arousal, attraction, and response components of sexuality.
Oxytocin, the neuropetide produced in the hypothalmus: “love hormone” influencing emotional and erotic attraction, attachment, and bonding
Levels increase as a person moves through sexual response cycle from initial excitement to orgasm for both sexes
Stimulates uterine wall contraction for women
Facilitates milk “let down” during breastfeeding
Autistic children have low levels of oxytocin, which is associated with reduced ability to form social attachments and express love

5. Sex Hormones in Male Sexual Behavior
Studies indicate testosterone has a greater effect on male desire than sexual functioning.
However, it also is involved with sensitivity, so a deficiency can decrease sexual pleasure.
Studies conducted with men who have been castrated have provided information about testosterone’s role in sexual functioning.
Antiandrogens: a class of drugs used to treat sex offenders and certain medical conditions like prostate cancer

6. Sex Hormones in Female Sexual Behavior
Estrogen contributes to:
General sense of well-being
Maintaining thickness and elasticity of vaginal lining
Vaginal lubrication
Desire-though some studies show in high doses can decrease it
Pleasure
Orgasmic capacity
Testosterone plays an important role as the major libido hormone

7. The Brain and Sexual Arousal
Mediator of thoughts, emotions, and memories
Sexual arousal can occur without any sensory stimulation through fantasies
Cerebral cortex; outer layer and thinking center of the brain that controls functions like reasoning, language, and imagination
Limbic system; subcortical brain system composed of interrelated structures (cungulate gyrus, amygdala, hippocampus, and parts of the hypothalmus) that influence sexual behavior in humans and animals
Studies show direct limbic stimulation produced intense sexual pleasure and orgasmic responses
In rats, hypothalmus stimulation triggered erection and ejaculation

8. Brain and Arousal
Dopamine; a neurotransmitter that facilitates sexual arousal and activity; testosterone stimulates the release of dopamine in both sexes
Serotonin; inhibits sexual arousal and activity
Male ejaculation causes a release of serotonin, which temporarily inhibits the release of dopamine. It also suppresses arousal by blocking oxytocin.
Antidepressant medication, selective serotonin reuptake inhibitors (SSRIs), increase serotonin levels in the brain and may interfere with libido and sexual response.

9. The Senses and Sexual Arousal
Touch
Most frequent source of arousal than any other stimulus
Primary erogenous zones: areas of the body densely covered with nerve endings
Genitals, buttocks, anus, perineum, breasts (particularly nipples), inner surfaces of thighs, armpits, navel, neck, ears, and the mouth (lips, tongue, entire oral cavity)
Secondary erogenous zones: areas that have become erotically sensitive through learning and experience
Vision
Smell
Taste
Hearing
What senses has greatest impact on sexual arousal and interaction? Do men and women differ in terms of what senses predominate during sexual intimacy?