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Lecture 13

PSYC 211 Lecture Notes - Lecture 13: Fallopian Tube, Vomeronasal Organ, Preoptic Area


Department
Psychology
Course Code
PSYC 211
Professor
Yogita Chudasama
Lecture
13

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PSYC211 Lecture 13 - Feb. 28
Reproductive Cycles:
Reproductive cycle of female mammals is called the estrous cycle (menstrual cycle in primates)
A female rat in estrous behaves differently which goads the male rat to behave differently as well
The sexual behaviour of mammals is linked with ovulation (in primates, females can mate anytime
during their menstrual cycle)
Menstrual and estrous cycles are controlled by hormonal secretions of the pituitary gland and
ovaries
Hormonal Control of Sexual Behaviour in Laboratory Animals:
Sexual behaviour in male rats depends on testosterone released by testes
A castrated male rat will cease sexual activity which can be reinstated with an injection of
testosterone
Sexual behaviour in female rats depends on estradiol and progesterone released by the ovaries
Ovariectomized rats are not sexually receptive but it can be produced by administering estradiol
followed by progesterone
Sexual Behaviour In Female Laboratory Animals:
When she is receptive, the female rat arches her back which elevates her hindquarters (lordosis)
Although a passive participant, she is active in initiating copulation; she may entice him by sniffing
an nuzzling the male genitals and make quick, short hopping movements with rapid ear wiggles
Male rats are most responsive to a female rat on ‘heat’
Males will ignore females whose ovaries have been removed but injections of estradiol and
progesterone will increase her attractiveness
2
Hormonal Control of Sexual Behaviour in
Laboratory Animals
!Sexual behaviour in male rats depends on testosterone
released by testes.
- A castrated male rat will cease sexual activity which can be
reinstated with a injection of testosterone.
!Sexual behaviour in female rats depends on estradiol and
progesterone released by ovaries.
- Ovariectomised rats are not sexually receptive but it can be
produced by administering estradiol followed by
progesterone.
Sexual Behaviour in Female Laboratory Animals
!When she is receptive, the female rat arches her back which elevates
her hindquarters (lordosis).
!Although a passive participant, she is active in initiating copulation;
she may entice him by sniffing and nuzzling the males genitals and
make quick, short hopping movements with rapid ear wiggles.
!Male rats are most responsive to a female rat on ‘heat.’
!Males will ignore females whose ovaries have been removed but
injections of estradiol and progesterone will increase her
attractiveness.
Presenting and
earwiggle approach Genital Investigation Mounting Lordosis and
intromission
Sexual Behaviour In Male Laboratory Animals:
Intermission (entry of penis into female vagina), pelvic thrusting (rhythmic movement of the
hindquarters) and ejaculation (semen discharge) are characteristics of all male mammals
When a male rat encounters a receptive female, he will spend more time sniffing, nuzzling and
licking her genitals, as well as mount her and engage in pelvic thrusting
He will mount her several times and intromit on most occasions but will ejaculate only after about
8-15 intromissions
After a refractory period, the male will return to copulate again
If the male is exhausted by repeated copulation with the same female, he will respond more quickly
if presented with a new female
Successive introductions with new females keeps up his performance for long periods of time
Behavioural Defeminization:
Androgens are male sex steroid hormones which stimulate the development of the male sex
organs
Androgens have a defeminizing effect; they inhibit the later development of anatomical or
behavioural female characteristics
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