(E2, L7) Female Reproductive Behavior

Question 1

What does estrus mean?

Answer 1

a female is in heat and will seek out and permit copulation

Question 2

What is anestrus?

Answer 2

a female is not in heat and will not permit and may even fight male conspecifics

Question 3

What is the estrus cycle?

Answer 3

releasing of the egg and the cycle that goes with it in females

Question 4

Why coordinate ovulation and sexual behavior?

Answer 4

• increasing likelihood of pregnancy
• limited # of eggs–> energetically expensive
• have to change motivation for certain rewards during different stages of cycle and life

Question 5

What is receptivity in female rodents?

Answer 5

when in behavioral estrus, a female will allow a male to mount her and demonstrate the lordosis posture: the characteristic mating posture the female will exhibit when hormonally primed (reflexive posture)

Question 6

What is proceptivity in female rodents?

Answer 6

-the extent to which a female initiates copulation
- this type of behavior encourages the male to engage in sexual activity
- may reflect her overt behavior and underlying motivational state
(this behavior will often illicit male sexual behavior as well)
(estradiol enhances proceptivity in the absence of male interest)

Question 7

What is attractivity in female rodents?

Answer 7

• the stimulus value of a female for a given male
• a hypothetical construct that must be inferred by observation of a conspecific’s behavior
• must always be measured in relational terms: that is, how attractive she seems based on the male’s actions
  (this changes during the estrus cycle)

Question 8

Describe the three-chamber preference test

Answer 8

There are three chambers: F, M, F, where the M can move freely between the Females. He will spend more time with a 0-M female than with a 2-M female (more attraction)

Question 9

What is the hormonal involvement in female rodents?

Answer 9

-estradiol and progesterone influence all components of female sexual behavior, with high levels of estradiol leading to increases in all three components of the activity
- female rodents will not engage in sexual activity without high levels of E&P

Question 10

Are females “active” participants in sexual behavior?

Answer 10

• prior to the mid-1970s, most researchers thought that females were passive recipients of male sexual attention
• but, often it is the female who initiates sex in many species
• its not that females have less sexual motivation, but perhaps we haven’t designed a way to see it
  -females have evolved to be choosy

Question 11

Describe the female rodents’ pacing of copulation

Answer 11

-females prefer to space out the amount of time between sexual contacts during copulation (females will usually leave for a bit and then come back)
- the more intense the stimulation, the longer she will take to return to the male

Question 12

why do female rodents space out interactions during sexual activities?

Answer 12

they are more likely to get pregnant if they space it out (pacing)
called the progestational reflex (more ejaculations and less intromissions)

Question 13

How can we measure motivation in animal models?

Answer 13

nose poke: she pokes it to open the door to the male

Question 14

What hormones prime the female for lordosis?

Answer 14

E and P, by increasing sensitivity to sensory input (rump area)

Question 15

Describe the mediation of lordosis in female rodents

Answer 15

sensory info comes in, which activates an interneuron and then results in lordosis (does not even reach the brain–like walking or knee jerk reaction)

Question 16

How do E and P act on the centra brain mechanisms in female rodents?

Answer 16

integrates the endocrine, social, and environmental stimuli coincident with mating (which includes behavior)

Question 17

What are the brain regions affected by E and P in female rodent reproduction?

Answer 17

Midbrain central gray
Medullary reticular formation
Lateral vestibulospinal and reticulospinal neurons
lateral vestibulospinal nucleus
midbrain reticular formation
(to name a few)

Question 18

What is the follicular phase in female humans?

Answer 18

the time of the menstrual cycle that begins at the end of menstruation and goes up to ovulation

Question 19

What is the luteal phase in female humans?

Answer 19

The portion of the menstrual cycle that begins at ovulation and continues until onset of menstruation

Question 20

Describe the ovarian cycle in rodents (graph)

Answer 20

Estrus: low everything
Diestrus I: GnRH increase
Diestrus II: same as diestrus I
Proestrus: increase of everything except GnRH which dips due to progesterone
Estrus: back to low everything (GnRH, LH, FSH (high across tbh), Estrogen, Progesterone

Question 21

Describe the ovarian cycle in rodents (GnRH)

Answer 21

• GnRh is released by the hypothalamus in brief pulses
• These pulses stimulate cells in the anterior pituitary to release follicle stimulating hormones (FSH) and luteinizing hormones (LH)
  
  • FSH causes follicles in ovaries to grow; as they do, they produce estrogens (E) and progestins (P)
• the pulse amplitude and frequency of GnRH continues to increase, and so do FSH and LH
• this leads to a surge in LG, which causes ovulation

Question 22

Describe the ovarian cycle in rodents (E)

Answer 22

• E falls back to baseline but P stays high for a short while (this high P is what inhibits GnRH from starting another cycle)
• if the egg is fertilized, what’s left of the follicle in the ovary will become the corpus luteum and increase P production (to maintain the pregnancy)
• if the egg is not fertilized, the corpus luteum breaks down, P is stopped and inhibition is lifted from GnRH
• the cycle resumes when pulses of GnRH begin to start the whole thing over

Question 23

How does the Pill work?

Answer 23

Oral contraceptives contain small amounts of synthetic hormones, which exert negative feedback on the hypothalamus, inhibiting GnRH
- Without GnRH, no FSH or LH is released, and the ovary does not release an egg for fertilization
(progesterone is the “break” of the system)

Question 24

What is the Lee-Boot effect?

Answer 24

When housed 4/cage with no males, female mice display longer estrous cycles due to lengthening of diestrous stage

Question 25

Whitten Effect (estrous induction and synchroniztion)

Answer 25

presence of a male or his odors induces estrous behavior within 48h in group-housed female mice. Exposure to male urine induces GnRH release and estrus

Question 26

Whitten Effect (suppression of estrus)

Answer 26

When housed >20/cage with no males, female mice suspend estrous cycles. Exposure to female urine suppresses GnRH release and estrus

Question 27

Bruce effect

Answer 27

pregnant females abort or resorb their fetuses if exposed to a male that was not the sire for >48 hours. Exposure to male urine induces GnRH release and estrous. This combination of endocrine events is incompatible with pregnancy

Question 28

Vandenbergh Effect (Acceleration of puberty)

Answer 28

Female juvenile mice exposed to adult males mature earlier than those not exposed to adult males. Exposure to male urine induces GnRH release and puberty

Question 29

Vandenbergh effect (delay of puberty)

Answer 29

Female juvenile mice exposed to adult females mature later than those not exposed to adult females. Exposure to male urine inhibits GnRH release and puberty

Question 30

What are environmental influences in human menstruation?

Answer 30

Human pheromones?
Lack of proper nutrition
Stress
Illness

Question 31

How do hormones affect human reproductive behaviors?

Answer 31

human and other primates are capable of engaging in sexual activity at any point in their cycle
- their receptivity is not tied to hormones, like in rodents and other species
Some studies show a peak in sexual motivation in women around ovulation
- self-reports of initiated sexual activities and erotic thoughts
T appears to be important too
- Women in monogamous relationships have lower T
- spikes in new relationships and then goes down

Question 32

How does the Pill alter sexual motivation in women?

Answer 32

in some cases, Pill users show increases in sexual activity because fear of becoming pregnant is lower
Many reports find that women on the Pill have reduced sexual motivation
- could be bc E levels are kept low
- T is also suppressed in women on the Pill

Question 33

Describe female sexual dysfunction

Answer 33

Reduced motivation:
- 63% of women ages 18-59 experience some form of female sexual dysfunction
- Low sexual desire (hypoactive sexual desire disorder; HSDD) is the primary reason women give for not having sex (not hormonally related)
- 30% of young or middle-aged women go through extended periods of little or no desire

Question 34

Describe HSDD

Answer 34

likely a disorder of the brain’s reward circuitry
- overactive or hyperfunctional inhibition of sexual reward circuitries
- recent imaging studies point to this hypothesis, indicating an overactive serotonin system can inhibit the DA sexual arousal system
- Underactive or hypofunctional sexual arousal circuitries

Question 35

Describe the female sexual response

Answer 35

Circular:
Seeking out and being receptive to:
sexual stimuli, biologic, sexual arousal, arousal and sexual desire, emotional intimacy, with spontaneous sex drive in the middle
(in some women, desire occurs during thte sexual response, not before)