COLLEGE OF MEDICINE, DEPARTMENT OF PSYCHIATRY, 4TH YEAR
TWANA A RAHIM
2012/2013
HUMAN SEXUALITY:
PREPARATION BY:
TWANA A RAHIM; FIBMSPSYCH, MBCHB
A.PROFESSOR OF PSYCHIATRY
DEPARTMENT OF PSYCHIATRY, FACULTY OF MEDICINE, HMU.
LECTURE OUTLINE:
- AIMS OF THE LECTURE.
- DEFINITIONS.
- SEXUAL CYCLE.
- EARLY SEXUAL DEVELOPMENT.
- INFLUENCES OF EARLY LIFE EXPERIENCES ON SEXULAITY.
- INFLUENCES OF CULTURE AND SOCIAL NORMS ON SEXUALITY:
- PSYCHOLOGY OF SEX.
AIMS OF THE LECTURE:
This ONE hour lecture has been involved at the fourth year psychology syllabus because SEXUAL LIFE is
considered as an essential element for humanity maintenance. Sexual motives are regarded to be the oldest
source of conflicts throughout human being cultures and history.
At the end of the lecture, candidates are expected to understand the meaning of the terms, features of sexual
cycle, and determinants of human sexuality.
DEFINITIONS:
1- Genetic Sex: refers to male karyotype (XY) and female karyotype (XX).
2- Sexual identity: refers to biologic sexual characteristics, such as genitalia, hormonal composition, and
secondary sexual characteristics.
3- Gender role: is the social behavior that allows others to categorize the person as male or female.
4- Sexual orientation: is the erotic attraction felt toward persons of the opposite gender (heterosexual), or of
the same gender (homosexual).
5- Gender identity: is the person’s sense of being male or female, rather than the biologic state of being male
or female. When this sense of identity is at variance with the anatomical sex, the person is said to be
complaining from Gender Identity Disorder.
SEXUAL CYCLE:
Arousal
Plateau
Desire
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Orgasm
Resolution
HUMAN SEXUALITY
COLLEGE OF MEDICINE, DEPARTMENT OF PSYCHIATRY, 4TH YEAR
TWANA A RAHIM
2012/2013
Sexual Cycle’s Responses:
Phase
Arousal
Plateau
Orgasm
Resolution
Woman
Clitoral enlargement
Ballooning of vaginal vault
Nipple erection
Clitoris retracts
Tenting of vagina
Bartholin’s secretion
Sex flush
Pelvic contractions
Increase in pulse and blood
pressure
Ejaculation
Clitoris return to normal size
Loss of vaginal congestion
Descent of uterus and vagina
Man
Penile erection
Testes elevate
Nipple erection
Increase in penile circumference
Testes increase in size
Cowper’s secretion
Sex flush
Contractions
Increase in pulse and blood
pressure
Ejaculation
Penile retraction
Testes descend
EARLY SEXUAL DEVELOPMENT:
Although we begin to mature sexually at puberty, the basis for our sexual identity is established in the
womb.
Determinants of human sexuality:
Two factors play important role in determining human sexuality:
1- Biological (Hormonal) Factor
2- Environmental Factor
Biological (Hormonal Factor):
For the first couple of months after conception, only the chromosomes of the embryo indicate whether it will
develop in to boy or girl. Up to this stage, both sexes are identical in appearance and have tissues that will
eventually develop into testes or ovaries, as well as a genital tubercle that will become either a penis or a
clitoris.
However, between 2 and 3 months, a primary sex gland (Gonad) develops into testes if the embryo is
genetically male (XY), or into ovaries if it is genetically female (XX).
Once testes or ovaries develop, they produce the sex hormones, which then control the development of the
internal reproduction structures and the external genitals. However, sex hormones are not too important in
later adult sexual expression.
The critical hormone in genital development is androgen testosterone. If the embryonic sex glands produce
enough androgen, the newborn will own male genitals; if there is insufficient androgen, the newborn will own
female genitals, even if it is genetically male(XY). On the other hand, if androgen is added artificially, the
newborn will develop male genitals even if it is genetically female (XX). I.e. the presence or absence of a
male (Y) chromosome normally influences sexual development only by determining whether the embryo will
secrete its own androgens or not. The anatomical development of the female embryo does not require
female hormones.
Androgen, after it has molded the genitals, begins to operate on the brain cells. Prenatal androgen changes
the volume and detailed structure of the cells in the fetus hypothalamus, an organ that regulates motivation
in human being. These effects of androgen essentially masculinize the brain, and may be responsible for
some masculine traits and behaviors that appear months or years later.
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HUMAN SEXUALITY
COLLEGE OF MEDICINE, DEPARTMENT OF PSYCHIATRY, 4TH YEAR
TWANA A RAHIM
2012/2013
Adult Sexuality:
Effects of Hormones on Desire and Arousal:
Although sexual arousal in other species is closely tied to hormonal level variation; in human, hormones
play only limited role in controlling sexual desire and arousal. On the other hand, sexual desire and arousal
seem to be more determined by psychological, social, and cultural factors in human being.
Biological (Neural Control):
The primary sex organ is the brain. The brain is where sexual desire originates and where sexual behavior
is controlled.
What are the sexual functions of brain in human?
1- Controlling the sexual thoughts, images, and fantasies which depend on the culture and social life of that
individual (cognition), and modulated through the processes of learning and conditioning from the early
childhood.
2- Production of the sexual hormones which determine the sexual organ development and phenotypes (female
vs. male body); sexual thoughts, images, and fantasies; as well as determining the production of semen and
ovum.
3- Moreover, nervous system including central and peripheral nervous systems (CNS and PNS) modulated by
sex hormones, controls the process of copulation through Sympathetic and Parasympathetic nervous
systems (SNS and PsNS), which in turn control skeletal muscles movements.
PNS
-
Erection determined by PsNS (Ach).
Ejaculation determined by SNS (NA).
Increased blood
flow to genitalia and
ERECTION
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Vascular
endothelium of
genitalia
Phosphodiesterase 5 enzyme inhibition
Viagra
Relaxation of
Convert
smooth muscles of
GTP to
arteries and corpus
cGMP
cavernosum
HUMAN SEXUALITY
Release of
NO in to
corpus
cavernous
Sexual
stimulation
Stimulate the
release of guanylate
cyclase
COLLEGE OF MEDICINE, DEPARTMENT OF PSYCHIATRY, 4TH YEAR
-
-
TWANA A RAHIM
2012/2013
Impacts of hormones and neurotransmitters on sexual cycle:
Hormones:
Testosterone increases desire in male.
- Androgen (testosterone and androsterone) increases desire in female.
(androsterone (from adrenal gland) is responsible for the first sexual feeling and attraction in both sexes at
about 10 years).
Estrogen decreases desire in male.
Prolactine decreases desire.
Cortisol decreases desire.
Neurotransmitters:
Nitrous Oxide (NO) = erection.
Acetyl Choline (Ach) = erection
Nor-Adrenaline (NA) = ejaculation
Dopamine (D) = desire and erection
Serotonin (5HT) = impairs whole sexual cycle
INFLUENCES OF EARLY LIFE EXPERIENCES ON SEXULAITY:
Human infants develop their first feelings of trust and affection through a warm and loving relationship with
mother or another primary caretaker. This basic trust is important for satisfactory interactions with peers.
Further, affectionate relationships with other youngsters of both genders form the bases for the intimacy
required for sexual relationships among adults. Therefore early unsatisfactory emotional life with the
surroundings affects later adulthood sexuality.
In addition, imitation of the role and identity of the parent or other adults of the same gender is the main
determinant for establishment of child’s Gender Role and Gender Identity.
INFLUENCES OF CULTURE AND SOCIAL NORMS ON SEXUALITY:
Unlike other primates, human sexual behavior is strongly determined by culture, religion, and other social
norms. Every society places some restrictions on sexual behavior. For example, incest is prohibited by most
societies, while other aspects of sexual behavior like homosexuality, sex among children, masturbation,
premarital sex, and even bestiality (sex with animals) are permitted in a varying degree in some societies
while prohibited in others. Further, these cultural norms may vary from time to time within the same culture
and country. For e.g. homosexuality nowadays become less stigmatized in western cultures than 3-4
decades ago, especially when it has been drawn out from mental illnesses. Moreover, although sex with
children or among children regarded as a crime in many modern societies, still its encouraged in some
primitive societies in Africa (particularly New Guinea), etc…
PSYCHOLOGY OF SEX:
Sexuality has been discussed within the context of psychology through 3 main psychological schools:
1- Freudian Psychodynamic aspect:
Freud proposed that every human being born with two main unconsciously determined instincts, sex and
aggression. These two instincts which are responsible for the conflict of {life (sex) and death (aggression)}
are responsible for the most neurotic symptoms which emerge to the conscious mind. It’s the suppression of
these two main instincts which lead to the emergence of anxiety symptoms and neurotic disorders.
Moreover, Freud postulated the psychosexual stages of development by dividing the development of the
psych of human being to 5 sexual stages: Oral, Anal, Phallic, latency, and Genital stages.
2- Learning Theories:
The process of learning plays a great role in determining Gender role, Gender Identity, and other aspects of
socially and culturally accepted sexual behaviors through the processes of Imitation, Conditioning, etc…
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HUMAN SEXUALITY
COLLEGE OF MEDICINE, DEPARTMENT OF PSYCHIATRY, 4TH YEAR
TWANA A RAHIM
2012/2013
3- Humanistic School:
Humanistic school is more concerned with human choice, creativity, self-actualization, and dignity.
Abraham Maslow, a humanistic psychologist, stated that in order for human being to reach the final stage of
Self-Actualization, he/she has to satisfy many other prerequisite stages which begin by satisfying the basic
physiological needs which include Sexual needs.
END
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HUMAN SEXUALITY