Control of sexual behaviour

Question 1

define appetitive behaviour

Answer 1

behaviour aimed at finding and obtaining a sexual partner

Question 2

define consummatory behaviour

Answer 2

behaviour of the actual sexual act

Question 3

what does external sexual stimuli refer to

Answer 3

usually opposite sex conspecifics
can be chemical signals unconsciously
learnt sensory modalities

Question 4

what does internal sexual stimuli refer to

Answer 4

hormones

Question 5

define pheromones

Answer 5

species typical molecules that trigger a specific response in another animal of the same species

Question 6

what are pheromones detected by in most mammals

Answer 6

detected by the vomeronasal organ

Question 7

why is the role of pheromones in humans controversial

Answer 7

Debate as to whether humans have a functional vomeronasal organ

Question 8

what other area is associated with detecting hormones

Answer 8

Olfactory epithelium

Question 9

evidence for role of pheromones in men

Answer 9

Women’s t shirts smell “sexier” during fertile phase of the menstrual cycle

Question 10

role of androstadienone (men’s sweat)

Answer 10

triggers alertness, good mood and sexual arousal in women (but poor mood in men)

Question 11

role of estratetrane

Answer 11

activates male but not female hypothalamic areas

Question 12

what does suppression of testosterone in males result in

Answer 12

reduces sexual interest - but not performance

Question 13

what does anticipation of a sexual encounter result in males

Answer 13

increased testosterone

Question 14

how does sexual interest vary in females

Answer 14

fluctuates with cycling ovarian hormones

Question 15

effects of androgens in females

Answer 15

testosterone from ovaries, androstenedione from adrenal gland
increase effect of oestradiol up to 3 times

Question 16

what are the 4 stages of arousal

Answer 16

• Excitement
  
  • Plateau
  • Orgasm
    Resolution

Question 17

what neurons are associated with excitement and plateau

Answer 17

Preganglionic neurons (nicotinic receptors)
Post-ganglionic neurons (muscarinic receptors)

Question 18

mechanics of excitement

Answer 18

Parasympathetic stimulation relaxes smooth muscle in blood vessels
More blood enters the genitals

Question 19

effects of more blood entering genitals

Answer 19

Penile/clitoral erection
Engorgement of the labia
Vaginal lubrication

Question 20

mechanisms of viagra

Answer 20

Smooth muscle relaxation involves signalling by nitric oxide
This increases the levels of cyclic GMP
Viagra inhibits the breakdown of CGMP by phosphodiesterase 5, keeping the smooth muscle relaxed

Question 21

why may erectile dysfunction occur

Answer 21

Stress leads to increase sympathetic activity, which causes vasoconstriction
Learned aversions can have central effects

Question 22

which part of the nervous system is involved in orgasm

Answer 22

sympathetic nervous system

Question 23

which neurons are involved in orgasm

Answer 23

Preganglionic neurons- acetylcholine (nicotinic receptors)
Post-ganglionic neurons -noradrenaline (noradrenergic receptors)

Question 24

what is orgasm triggered by

Answer 24

combo of local stimulation and central input

Question 25

mechanism of orgasm

Answer 25

Sympathetic stimulation and pulsatile release of oxytocin - series of smoot muscle contractions in the pelvic floor Requires disinhibition by the central nervous system

Question 26

how does central inhibition of orgasm work

Answer 26

Nucleus paragigantocellularis (nPGi) in medulla inhibits orgasm circuitry in lumbar spinal cord (serotonin) During intercourse, hypothalamus inhibits the peri-aqueductal gray (PAG) which normally stimulates nPGI

Question 27

how does resolution take place

Answer 27

During orgasm - blood oxytocin levels peak (involved in pair-bond formation) Prolactin released - high levels suppress sexual motivation