Physiology: Sexual Action and Response

• Physiology of Sexual Action and Sexual Response are key areas of study
• Asst. Prof. Tulay KAVLAK prepared this lesson

Presentation Plan

• Female and male anatomy are reviewed
• The limbic system is discussed
• The autonomic nervous system gets explained
• Endocrine basis of female and male sexuality are reviewed
• Physiology of sexual action is explained
• Sexual response in men and women are discussed

Female Anatomy - Labia Majora

• It is a fold of fat and connective tissue that extends from the mons pubis
• It is covered with hairs after puberty
• Labia majors protect the labia minora, urethral and vaginal opening
• It has many veins and nerves

Female Anatomy - Labia Minora

• Labia minora are located below the labia majora
• Like the labia majora, they are rich in vessels and nerves
• Labia minora are covered with a thin layer of epidermis
• They contain no hair follicles

Female Anatomy - Clitoris

• The clitoris is located at the top of the labia minora
• It is a short, cylindrical, erectile organ
• Due to the abundance of veins and nerves, tears and injuries can cause heavy bleeding

Female Anatomy - Vestibule

• The vestibule is a triangular field formed by the opening of the labia minora
• The urethra and vagina open to the vestibule
• Bilateral Bartholin glands and the hymen reside in the outer part of the vestibule
• The vestibule's thin mucosal structure is susceptible to irritation from chemicals, heat, discharge, and tight clothing

Female Anatomy - Hymen

• The hymen is an elastic mucous membrane that partially covers the vaginal opening
• Holes present allow menstrual blood to flow out
• If the hymen is fully closed it's called imperforated hymen, menstrual blood cannot flow out and would require a hymenotomy

Female Anatomy - Bartholin Glands

• They are the largest glands in the vulva
• Found on both sides of the vagina, opening into the vestibule via ducts
• Bartholin glands lubricate the vagina by secreting secretions during sexual stimulation

Female Anatomy - Vagina

• The vagina is an 8–10 cm tubular structure of muscles and membranes connecting the vulva to the uterus
• In the unborn, the front and back walls touch each other
• The vagina's upper part, "Porsio", wraps around the cervix from the outside, adhering firmly
• Recesses between porsio and vaginal walls also are "Fornix"
• Vaginal mucosa has layers called rugae for expansion during childbirth
• The vaginal mucosa responds to estrogen and progesterone, therefore it is acidic
• In menopause, pH shifts alkaline, causing senile vaginitis (aging infection)
• Vagina serves as birth canal and channel for menstrual blood, with coitus occurring here

Male Anatomy - Penis and Scrotum

• The penis and scrotum are the male reproductive organs

Male Anatomy - Penis

• Cylindrical spongios (spongy) layers inside
• 2 corpus cavernosa
• Corpus spongiosum
• The urethra is in the corpus spongiosum
• Blood vessels and nerves in the spongios layer
• Blood vessel fullness in this layer during sexual excitement causes erection
• Tip is the glans penis
• Rich in nerve endings which makes it very sensitive

Male Anatomy - Scrotum

• It carries the testicles and spermatic cords
• Inside spermatic cords: blood vessels, nerves, muscle fibers, ductus-vas deferens (sperm path)
• The spermatic cord enters the abdomen through the inguinal canal
• The mens internal reproduction organs are the duct system that provides the storage and transport of the testicles and spermatazoon

Male Anatomy - Testicles

• They are a pair and located inside the scrotum
• They are 4cm long
• Each is suspended inside the scrotum by the spermatic cord (Funiculus spermaticus)
• The spermatic cord is made up of seminal ducts, arteries, veins and lymphatic vessels and nerves
• The testicle has two functions
• Exocrine task - Sperm creation
• Endocrine function - Hormones creation

Physiology of Sexual Behavior

• Limbic system
• Autonomic nervous system
• Central nervous system
• Medulla spinalis

Role of Limbic System

• It controls affective state and factors that motivate action, especially regarding fear, anger, and sexual behavior
• Limbic system defined as the brain's network, regulates basic functions such processing and regulating emotion and memory, as well as sexual arousal and learning
• Located in the lower right side of the cerebrum and on either side of the thalamus, the limbic system controls emotional reactions
• A process that goes wrong in this part can trigger psychological processes and cause negative consequences
• Limbic system also referred as the emotional brain consist of four parts hypothalamus, hippocampus, thalamus and amygdala

Functions and Tasks of the Limbic System

• Behaviors necessary for sustaining existence eating drinking, anger, rage, fighting, escape and evasion reactions when confronted with an angry enemy
• Behaviors related to the continuation of existence and species behaviours related to coupling, reproduction, offspring care and nurture
• And adaptation of visceral activities in relation to behaviors

Motor Systems

• There are two parts of the nervous system that control motoric functions
• Somatic motor system (works voluntarily)
• Autonomous engine system (works involuntarily

Autonomic Nervous System and its Functions

• It consists of nerve fibers without a myelin sheath
• This controls the operation of involuntary activities
• This is divided into two parts
• Sympathetic nervous system mostly activated in times of stress, danger
  • Speeds up the vessel beats, speeds up breathing, Brooches expand, Pupils dilate and Sweating increases
  • Increases blood sugar and capillaries constrict and saliva secretion is reduced
  • Movements of stomach/intestines decrease in digestion which slows down and kidney activity and The bladder relaxes
• Parasympathetic nervous system normalizes the organs after stress
  • Salivation increases
  • Digestion is accelerated
  • Kidney activity increases as excretion accelerates
  • Bladder contract
  • Cap beats slow down and breathing slows down
  • Brooches narrow, pupils shrink and sweating is reduced
  • Lowers blood sugar and capillaries dilate

Neuroendocrine Regulation of Sexual Function

• Sexual response determined by interplay, sexual organs, nervous/endocrine systems, neurochemicals and psychological processes
• Diseases and adverse environmental conditions affect sexual function
• Signals from genitals/other areas focused in brain which sends impulses via nerves/spinal cord
• The genitalia and pelvic floor muscles are regulated by parasympathetic system as well as somatic

Role of Hypothalamus

• Coordination of somato-motor visceral-motor activities
• Body water balance and control of thirst
• Body weight control
• Control of reproduction and sexual behavior
• Regulation of body temperature
• Regulation of sleep and wakefulness
• Controlling Excitement, Fear and Anger
• Control of the endocrine system

Brain Regions

• MYELENCEPHALON - Medulla oblangata, Reticular formation
• METENCEPHALON - Pons, Cerebellum
• MESENCEPHALON (midbrain) - Cerebral aquaduct, Corpora quadrigemia, Cerebral peduncles, Red nucleus, Substansia nigra
• DIENCEPHALON (arabeyin) - Thalamus, Hypothalamus-pituitary, epithalamus

Hormones of Pituitary Gland

• First in line in the hormones are estrogen and progesterone
• Produced by the ovaries under control of gonadotropin hormone
• Estrogen maintains the normal condition of the vagina, and is responsible for lubrication during sex
• Androgens, made in adrenal cortex/ovary and levels change slightly during ovulation, but are involved in sexual intent, desire and wanting
• Androgen is associated to sexual interest, desire and wanting
• Oestrogen dictates desire for intercourse
• Progesterone suppresses feelings of active intimacy and improves feelings regarding maternity and cuddling
• Basic sex hormones include testosterone, dihydrotestosterone, androstenedione
• Testosterone/androstenedione are produced and under control to LH and androgens produces in adrenal glands
• Testosterone maintains s3xual interest and is not directly involved in erection

Action of Sexual Function

• Human sex response, normal inactive
• Which prepared genital organs for that
• Highly organized
• Regular by biochemical, physiological and psychological processes

Female Sexual Behavior

• Although masters and Johnson emphasize women a3cumulation independent which turn via nerve
• The woman participates more with her brain than men in an effort to connect
• As that in women dysfunction as quite different
• Arousal and orgasm are the 4 responses according to masters, Johnson divided sexual responses

Sexual Response Cycle

• The initial response includes the pleasure.Masters and Johnson separated and sexual stimuli to four which eventually was added
  • Desire phases
  • Arousal phases
  • Plateau phases
  • Orgasm phases
  • Solution phases
• 15141 is a sexual which emergence and many years
• It’s mainly and for the stimulus
• The may occur as many
• If there is enough appropriate sexual continues

Phases of Female Arousal

• Occurs over hours or minutes based on duration of phase
• Most often is the wet lining of the vagina, where mucus increases
• Lubrication for penis and lack of it called dyspareunia or intercourse infection, estrogen
• The middle part makes an erection and is stimulated
• There is psycho stimulus
• Women experience a erection and breast volume

G Spot

• Spot has a sensitive area
• In vaginal contact stimulation
• Is a main that generate changes like partnership

Arousal Phase Male anatomy

• Reactions, and of stimulus in bodies
• Even prevent infection

During Excitement

• Gland testicles flow much and rises in areas
• There is about 3 to 6 contract in 0.8 to 1 s
• 60 amount