Topic 2 - Control of Sexual Behaviour

two stage sof sexual behvaior

• appetitive behvior

• consummatory behvior

Appetitive Behaviour:

Behaviour aimed at finding and obtaining a sexual partner

Consummatory Behaviour:

Behaviour of the actual sexual act

Appetitive Behaviour: Sexual Motivation

• external

• internal

external Appetitive Behaviour: Sexual Motivation

•        Usually related to opposite-sex conspecifics

•        Can be chemical stimuli we’re not consciously aware of (pheromones)

• Can also be learned and of different sensory modalities

internal Appetitive Behaviour: Sexual Motivation

•        Hormones

•        Brain mechanisms

Pheromones:

species-typical molecules that trigger a specific response in another animal of the same species (e.g. sexual interest)

Putative role of pheromones in human sexual interest

•        In other mammals, pheromones are detected by the vomeronasal organ- sepracte organ in the nasal passage

•        There is debate about whether humans have a functional vomeronasal organ- we dont have a distinction of a spefic organ

•        Olfactory epithelium can detect some pheromones in humans (and pigs)- thay have detection in the nasal cavety without a specific organ

so it may be the case that phemones do effect humans

what effect can pheromons have

• Women’s t-shirts smell sexier during fertile phase of menstrual cycle- t shirt study about wether they think thay are attrective - smell sexier - unconsous

•       Androstadienone (in men’s sweat) triggers alertness, good mood and sexual arousal in women (but poor mood in men)- place on the upper lips of participants

•         Estratetraene activates male, but not female hypothalamic areas. third trimester of pregnacey in urine

• armpits and grouns have hair to spred pheromones

femal and make molectules thay are thought to be the phemone molecules in humans

•         Estratetraene female

•       Androstadienone male

Role of sex hormones in sexual interest males

•        Suppression of testosterone (T) reduces sexual interest (but not performance)

its in between their own levels not leves on avrage of males

•        Anticipation of sexual encounter increases Testotrone

dosnt effect the factc to have ahveing an erection

•        No correlation with individual differences in T

•        Only motivation that is changes- sexual preditors not chanage who they are into

Role of sex hormones in sexual interest Females:

•        Sexual interest fluctuates with cycling ovarian hormones (esp. oestradiol)

•        Androgens (testosterone from ovaries, androstenedione from adrenal gland) increase effect of oestradiol up to 3 times

•        Increase in T in females also with anticipation of sexual activity

Fluctuation in sexmotivation in teh menstaral cycles

increases over ovvulation

decreases in midlutial

slightly more in the premestral than middlutial

Similar patterns for masturbation

Shows the menstarl cycle and plots the percentage- lon term hetrosexal cupple

-            Innituate the sex

Testosterone in females responds to anticipated sexual activity

Long distance cupples – when come together they wil have sex

Mesure the t at baseline- day to day

Day before visted, after visting patnerthay have an increase in T

consummatory sexual behvior: 4 stagges of arousal

-            Excitement

-            Plateau

-            Orgasm

-            Resolution

Excitement and Plateau: Parasympathetic Nervous System

• early stages of phyiilogocal arousal for an exrection and clit growing and lubrication

parasypathetic nerouvs systen orgnised into two stages

• pregangual neurons - acetylechline (mnicinic receptors)

• postagngulan nerons - acetylcholine (muscarine receptors

• pregangual neurons -

nerons taht sit begfore the ganaggulan

ganalgulan is a group on neralic cell bodies witch stit nxt to the target orgens

use acetecholone

niciten receptors

postagngulan neron

sit behind the agangilion onto the organs

uses acetylechline

musscarine receptors

Excitement and Plateau: the Mechanics

•        Parasymphathetic stimulation relaxes smooth muscle in blood vessels

•        More blood enters the genitals

into cavities with make the dick clit swell up

•        Penile/Clitoral erection (“tumescence”)

•        Engorgement of labia

•        Vaginal lubrication

•        Smooth muscle relaxation involves signalling by Nitric Oxide (NO)- if the blood goes in the to prevent it from going back out again muscle

•        This increases the levels of cyclic GMP (cGMP)- responsible for the relaxation

how Viagra works

•        Viagra inhibits the breakdown of cGMP by Phosphodiesterase 5 (PDE5), keeping the smooth muscle relaxed

• dost cause an erection just keeps the erection going

the excitment cercit

5 is post gangilonic

4- pre ganglioninc

3 exictory inter neron in spinal cord- witch get input from 3 diffrent places

2- first ordern nreon of the sensroy system in the spinal cord witch gets stimulated by

1 witch is a sesory neron a perifiral sensory neron- sensation in genitasl

6&7 are exitory adn inhibitory input form the barin

• local reflex arc just ahppinging in the area - soinal cord damage it happens but cant feel

system

1. sensory imput

2. periphiral sesnory nuron

3. first ordern nreon of the sensroy system in the spinal cord

4. inter exctory spinal neon witch can also be stimulates by

5. extatory or inhibitory brain nerons from the spine

6. pregangulan

7. postgangula

8. to gentials

erectial disfunction

-            Always “physical”

-            Stress leads to increased sympathetic activity, which causes vasoconstriction

-            Learned aversions can have central effects

-            Many of these are difficult to tease apart

Orgasm: Sympathetic Nervous System