reproductive behaviour and ECDs Flashcards
1
Q
sexual behaviours
A
set of actions with the primary aim of ensuring that the male sperm is delivered successfully to the female ova
2
Q
sex drive/libido
A
motivational force that drives individuals to seek out members of the opposite sex and copulate with them
3
Q
physiological costs of sexual behaviour
A
female eggs are ‘expensive’ to produce
they are limited in supply
whereas male sperm is cheap
4
Q
T/F: for most animals, sexual behaviours occur in a sequence of fairly well-defined stages
A
true
at each stage, individual must be responding to both internal and external factors, each of which has some influence on current behaviour
5
Q
initially, sexual behaviours were defined in terms of…
A
appetitive stage
consummatory stage
this two-stage distinction has since been applied to other behaviours:
- feeding
- aggression
- drug-taking behaviours
6
Q
appetitive behaviours
A
bring the individual into contact with the particular goal at hand
ie. brings you close to a sexually receptive individual
7
Q
consummatory behaviours
A
performed when individuals are in contact with their primary goal
tend to be more highly stereotyped and species-specific
probably innate
8
Q
4 components of male sexual behaviours
A
- mount latency
- intermission latency
- ejaculation latency
- post-ejaculatory refractory period
9
Q
mount latency
A
time from when a male and female are first introduced to when the first mount occurs
10
Q
intermission latency
A
time from when they are first engaged in penile penetration
11
Q
ejaculation latency
A
time between the first intromission and ejaculation
12
Q
post-ejaculatory refractory period
A
time between ejaculation and resuming sexual search
13
Q
3 components of female sexual behaviours
A
- attractivity
- proceptivity
- receptivity
14
Q
attractivity
A
stimulus value of the female to a male
ie. if male chooses to spend more time with a particular female
15
Q
proceptivity
A
extent to which a female will initiate socio-sexual encounters with males
thus reflects both her overt behaviours and her underlying motivational state
16
Q
receptivity
A
state of responsiveness of the female to the sexual initiation of the male
ie. lordosis
17
Q
A
18
Q
the shorter the latencies of components of male/female sexual behaviour…
A
the stronger the sex drive
19
Q
pheromones - hormones/sexual behaviours in male animal models
A
smearing immobilized male hamsters with vaginal secretions from estrous female
leads to other males attempting to mount these hapless males
immobilized males free from pheromones did not elicit this behaviour in other males
20
Q
reductions in mount latency can result from what 2 things? animal models
A
- exposure to pheromones 10 mins before meeting receptive female
- injections of testosterone
21
Q
period of max sexual receptivity in females
A
ESTRUS phase of the cycle
aka “heat”
period of max sexual receptivity and fertility
males are most attracted to females in “heat”
22
Q
injections of ______ could serve just as well as testosterone in promoting masculine sexual behaviours
A
estrogen
hypothesized that testosterone exerts its neurological effects after being converted into estradiol via aromatase
so it’s not only testosterone - because testosterone likely must be converted into estrogen to have effect
23
Q
essential brain region to control of sexual performance in male rats
A
preoptic area (POA)
appears especially important for integration of:
- environmental
- physiological
- psychological info
prior to and during successful copulation
24
Q
POA lesions
A
reduce/eliminate male sexual behaviour
virtually in every vertebrate species
POA lesions destroy connections to dopaminergic nerons in VTA
impairs POA regulation of dopaminergic activity
25
preoptic neurons project...
to several brain regions
including dopaminergic neurons in VTA
26
drugs that increase dopamine synthesis/stimulate postsynaptic dopamine receptor sites...
should also facilitate copulatory behaviour in males
27
beyond testosterone, approx 50% increase of extracellular dopamine in mPOA is associated with...
higher copulation
regardless of testosterone concentrations
28
sexual desire
subjective psychological state in which individual displays interest in sexual stimuli
motivated towards seeking sexual activities
though may not be sexually aroused
29
sexual arousal
2 part process
1. physiological: genital sexual arousal
2. subjective awareness that one is genitally and/or physiologically aroused
30
how to measure sexual desire?
questionnaires, surveys
- "top 50 reasons why men have sex"
31
how to measure sexual arousal?
objective measures:
- heart rate
- blood pressure monitoring
- latency to achieve orgasm
- measurement of penile erection via penile plethysmograph
32
penile plethysmograph
measures volume of displaced air as penis enlarges
designed to prevent young males from avoiding military service by pretending to be homosexual
device = placed over penis, shown erotic heterosexual material
air displacement would provide evidence of their "manliness" to fight
33
hypogonadism
condition in which the body produces insufficient levels of sex hormonees
34
effects of testosterone treatment on hypogonadal men SETUP
men with low concentrations of blood plasma testosterone (<3 mg/ml) received 3 injections 6 weeks apart
1. placebo
2. low dose (100 mg)
3. high dose (400 mg)
35
effects of testosterone treatment on hypogonadal men RESULTS
patients' self-reports indicated the incidence of erections and certain sexual behaviours also increased in dose-dependent manner
36
testosterone treatment effects on sexual behaviour in men with regular levels of testosterone?
weak evidence
testosterone intervention groups showed increase only for the search of auditory or visual sexual stimuli
other behavioural measures (ie. masturbation, sexual intercourse etc) showed no differences between the groups
currently: understood that once a threshold of serum testosterone has been achieved (low normal range) this is sufficient to normalize sexual function/motivation
- increasing testosterone levels to high normal range had no additional effect on sexual behaviours
37
understood that once a threshold of serum testosterone has been achieved...
understood that once a threshold of serum testosterone has been achieved (low normal range) this is sufficient to normalize sexual function/motivation
increasing testosterone levels to high normal range had no additional effect on sexual behaviours
38
4 phases of the menstrual cycle
1. menstrual phase (days 1-5)
2. proliferative phase (days 6-14)
3. ovulation (day 14)
4. secretory phase (day 15-28)
39
menstrual phase (day 1-5)
when uterine lining, which has thickened in prep for pregnancy, is shed in the absence of fertilization
menstrual bleeding - 3-7 days
shedding of endometrium is triggered by decrease in estrogen and progesterone levels
40
what triggers the shedding of the endometrium?
a decrease in estrogen and progesterone levels
41
proliferative phase (day 6-14)
following menstruation
begins as ovaries, in response to FSH, start to produce increasing amounts of estrogen
estrogen stimulates growth and thickening of endometrium, preparing it to receive a fertilized egg (embryo) in the event of conception
42
ovulation (day 14)
ovulation = midpoint of menstrual cycle
triggered by surge in LH from pituitary gland
LH causes the dominant ovarian follicle to release a mature egg (ovum) into the fallopian tube
most fertile period of menstrual cycle
43
most fertile period of menstrual cycle
ovulation
44
secretory phase (day 15-28)
after ovulation
secretion of progesterone from corpus luteum (which forms from collapsed ovarian follicle after ovulation)
progesterone helps to further thicken the endometrium, making it more conducive to embryo implantation
if fertilization and implantation don't occur, corpus luteum regresses, leading to decline in progesterone levels
45
facial preference test: women during different phases of menstrual cycle
women in FOLLICULAR phase = attracted to more MASCULINE faces
46
4 correlational findings associated with follicular phase
1. greater preference for more masculinized and symmetrical male faces
2. in short-term relationship, preference for masculanized
3. higher level of sexual arousal (subjective and objective) in experimental sexually eliciting setting
4. higher probability of short-term encounters, and flirting with men other than current partner
47
4 correlational findings associated with luteal phase
1. preferences for apparent health displayed in male faces
2. such preferences for apparent health = stronger in pregnant women and women using oral contraceptives
3. estimated progesterone levels = positively related to preferences for femininity in male faces
4. women in stage of high estimated progesterone showed more commitment to their relationships
48
female body odour as potential cue to ovulation t-shirt study SETUP
women were asked to wear t-shirt for 3 consecutive nights during late follicular (ovulatory) phase
and another t-shirt during the luteal (non-ovulatory) phase
male raters judged the odours of the t-shirts in terms of sexiness and pleasantness
49
female body odour as potential cue to ovulation t-shirt study RESULTS
ratings of sexiness and pleasantness were almost 4 times higher for the follicular phase t-shirts
a subsampling were OVULATING as well - and these t-shirts had even higher ratings
50
female body odour as potential cue to ovulation t-shirt study - findings were replicated with...
ratings of PICTURES
pictures of women with HIGHER ESTROGEN levels = viewed as MORE FEMININE, ATTRACTIVE and HEALTHY than those representing females with lower estrogen levels
51
menstrual cycle and contraceptive pills
normal menstrual cycle:
a) estrogen peaks during follicular phase
b) progesterone peaks during luteal phase
on the pill:
a) active pill phase (day 1-21)
- prevent ovulation by inhibiting release of FSH and LH hormones from pituitary
- high progesterone
b) placebo/inactive pill phase (day 22-28)
- progesterone drops
estrogen is super low the whole time
52
what is a result of pill-users having more stable levels of progesterone and estrogen throughout the cycle?
lower sexual behaviour variations
in this scenario, testosterone is more relevant
in pill users, FREE TESTOSTERONE = significantly positively related to multiple measures of sexual behaviour
53
in pill users, testosterone is significantly positively related to...
1. sexual thoughts
2. sexual desires
3. anticipation of sexual acitivity
54
face preference in long-term context for pill users versus non-pill users
normally cycling women: prefer FEWER MASCULINE faces in long-term context compared with short-term context
in pill users, this difference disappeared
55
men show preference for women in what phase of the menstrual cycle?
fertile phase
at least when it comes to a short-term context
BUT in pill users, there was no change in their attractiveness to males during the fertile phase - suggests the pill interrupts cycling attractiveness of women towards men
56
6 main summary points
1. sex steroid hormones clearly don't act as a "switch" to activate sexual behaviour. presence of testosterone doesn't automatically stimulate mating behaviour; rather, testosterone/its metabolites increase the probability that a sexual behaviour will occur in presence of specific stimuli
2. mPOA appears crucial for integrating sensory and internal stimuli in order for normal copulation to occur
3. testosterone must be converted into estrogen to have behavioural effects in males
4. estrogen = primary female sex hormone and fluctuates throughout menstrual cycle, peaking during follicular phase
5. progesterone is another important female sex hormone, produced primarily during luteal phase (after ovulation). modulates effects of estrogen on sexual arousal and behaviour. potentially impacts sexual activity and interest at diff points in cycle
6. contextual psychological factors and relationship dynamics also play significant roles in shaping female sexual behaviour
57
EDC background
endocrine disrupting chemicals
man-made chemicals have become part of everyday lay
some of these chemical pollutants can affect endocrine system
interfere with important developmental processes in humans and wildlife
58
3 strands of evidence for concerns over EDCs
1. high incidence/increasing trends of many ENDOCRINE RELATED DISORDERS in humans
2. observations of endocrine-related effects in WILDLIFE populations
3. identification of CHEMICALS with endocrine disrupting properties linked to disease outcomes in lab studies
59
number of chemicals known/suspected to be able to interfere hormone receptors, hormone synthesis or hormone conversion
800
however, only a small fraction of these chemicals have been investigated in tests capable of identifying overt endocrine effects in intact organisms
60
what are EDCs?
endocrine disrupting chemicals
EXOGENOUS substance/mixture that alters function(s) of endocrine system
consequently causes adverse health effects in organism/its progeny
61
diverse systems affected by EDCs likely include...
all hormonal systems
range from controlling development/function of reproductive organs
to the tissues/organs regulating metabolism and satiety
62
10 key characteristics of EDCs
1. receptor ligand or agonist
2. receptor antagonist
3. receptor expression
4. signal transduction
5. epigenetic alterations
6. hormone synthesis
7. hormone transport
8. hormone distribution or circulating hormone levels
9. hormone breakdown or clearance
10. fate
can interfere in almost any component of the endocrine system
63
EDC examples
1. PESTICIDES: DDT, chlorpyrifos, atrazine
2. CHILDREN'S PRODUCTS: lead, phthalates, cadmium
3. FOOD CONTACT MATERIALS: BPA, phthalates, phenol
4. ELECTRONICS/BUILDING MATERIALS: brominated flames retardants, PCBs
5. PERSONAL CARE PRODUCTS, MEDICAL TUBING: phthalates
6. ANTIBACTERIALS: triclosan
7. TEXTILES/CLOTHING: perfluorochemicals
64
POPs
persistent organochlorine pollutants (POPs)
persist a long time in environment
high toxicity
bioaccumulate
65
4 examples of POPs
1. polychlorinated biphenyls
2. organochlorine pesticides (OCPs)
3. plasticizers and nonyphenols
4. heavy metals
66
BPA stands for...
bisphenol A
67
BPA - 4 points
1. found in plasticizers
2. known deleterious mechanism of action on ESTROGEN and ANDROGEN receptors
3. hormones important for female and male sexual/reproductive development
4. BPA has been linked to hormone-related side effects including INFERTILITY, and BREAST/PROSTATE CANCERS
68
6 routes of exposure to EDCs
1. oral consumption of contaminated food/water
2. contact with skin and/or inhalation
3. intravenous
4. application to skin
5. biological transfer from placenta
6. biological transfer from mother's milk
69
EDC exposure: oral consumption of contaminated food/water
1. industrial waste/pesticides contaminating soil or ground water
2. leaching of chemicals from food/beverage containers, pesticide residues in food/beverage
PCBs, DDT, BPA, phthalates...
70
EDC exposure: contact with skin and/or inhalation
1. household furniture treated with flame retardants
2. pesticides used in agriculture, homes, or for public disease vector control
BFRs, DDT, chlorpyrifos...
71
EDC exposure: intravenous
intravenous tubing
phthalates
72
EDC exposure: application to skin
some cosmetics, personal care products, anti-bacterials, sunscreens, medications
phthalates, triclosan, Parabens, insect repellants
73
EDC exposure: biological transfer from placenta
maternal body burden due to prior/current exposures
numerous EDCs can cross placenta
74
EDC exposure: transfer from mother's milk
maternal body burden due to prior/current exposures
numerous EDCs are detected in milk
75
EDC exposure during sensitive windows of development
more detrimental during certain stages
sensitivity to endocrine disruption is HIGHEST during TISSUE DEVELOPMENT
effects of adult exposures seem to go away when the EDC is removed
TIMING of exposure is CRITICAL
76
because of endocrine system's critical role in so many important physiological functions, impairments in any part of the endocrine system can...
lead to disease or even death
by interfering with body's endocrine systems. EDC exposure can therefore perturb many functions
77
biomonitoring
measurement of chemicals in body fluids and tissues
78
biomonitoring shows that...
nearly 100% of humans have a man-made chemical body detectable in...
blood, urine, placenta, umbilical cord blood, body tissues like adipose tissue (fat)
79
EDCs and female reproductive functions
antagonists of estrogen/progesterone receptors in females
1. disrupted hormone action
2. irregular cycles
3. decreased fertility
4. infertility
5. polycystic ovarian syndrome
6. endometriosis
7. hormone sensitive cancer
8. precocious/delayed puberty
9. adverse birth outcomes
80
some known mechanisms of EDCs on female reproductive functions
EDCs interfere with:
1. estrogen hormone receptors
2. enzymes involved in ovarian steroidogenesis
3. folliculogenesis
81
EDCs can affect male reproduction by...
1. decrease in sperm count, reduced sperm motility and abnormal sperm morphology
2. undescended testis, prostate and testicular cancer
3. inhibition of 5 alpha-reductase
82
what's been happening to the adverse effects of EDGs on male reproductive functions in the last decades?
increasing significantly
83
what has been linked to abnormal sperm morphology, count and motility?
occupational exposure to pesticides
BPA especially
84
5 alpha-reductase deficiency
genetic males (XY) with 5 alpha reductase deficiency = born with ambiguous genitalia, small/undescended testes
usually considered female at birth, reared as females
at puberty, when testosterone masculinizes body (male-typical musculature and auxiliary hair growth)...
genitalia develop to resemble male-typical penis and scrotum
85
recent evidence shows that Y/X ratio of live spermatozoa was significantly...
LOWER in sperm treated with EDCs than control spermatozoa
86
EDCs affect what 3 other endocrine pathways?
1. thyroid hormones
2. fat tissue hormones
3. adrenal hormones
87
EDCs and thyroid hormones
EDCs can disrupt the:
- production
- transport
- metabolism
- signalling
of thyroid hormones (T3 and T4)
main associations: hypothyroidism, hyperthyroidism, thyroid cancer
88
EDCs and fat tissue hormones
EDCs have also been linked to disrupting HYPOTHALAMIC CONTROL of food intake and energy balance
main associations: POPs are known to bioaccumulate in body fat, stimulate adipogenesis - leading to obesity
89
EDCs and adrenal hormones
various steps in adrenocortical steroidogenic pathway may be disrupted by exogenous chemicals
main associations: interfere with synthesis of cortisol and adrenaline within adrenal gland, leading to hormone level imbalances
90
EDCs and risk for type 2 diabetes
EDCs may direct INTERFERENCE with GLUCOSE METABOLISM and lead to type 2 diabetes
DDT and BPA = shown to cause GLUCOSE TOLERANCE and disruption of insulin secretion
91
EDCs and type 2 diabetes: association studies with humans have shown...
1. polychlorinated biphenyls (PCBs) serum levels associated with diabetes in women
2. dioxins, pesticides and BPA are related to prevalence of diabetes
92
recommendations to prevent EDC exposure
1. pregnant women should avoid contact with and inhalation of chemicals
2. children should be protected from chemical insults
3. one should avoid consumption of chemical and contaminated food/water/swimming
4. plastic, nonylphenols, petroleum products and industrial fluids shouldn't be burned
5. hot drinks in plastic cups should be avoided because plasticizers leach into the fluid when warm
6. glassware is recommended for consumption of warm food/drinks
7. warm pudding/similar foods shouldn't be served in plastic cups/plates
93
PFOA is used to...
make Teflon
but Teflon has been PFOA-free since 2013
today's nonstick/Teflon cookware is considered safe for everyday home cooking, as long as temperatures don't exceed 500 degrees F/260 degrees C
