MIDTERM 2 Flashcards
What are the main characteristics of prolactin?
Produced by anterior pituitary in response to prolactin-releasing factor in hypothalamus.
In females – role in lactation and milk production after childbirth (rising during pregnancy in preparation).
In males – many functions, such as regulating immume system, metabolism and reproduction (sperm production and testosterone levels).
What are the main characteristics of oxytocin?
Produced in hypothalamus and released by posterior pituitary gland.
Involved in:
- Labor and childbirth (contractions, milk ejection)
- Maternal behaviour (love or bonding hormone for touch and attachment)
- Stress regulation (attenuates release of cortisol)
- Social behaviour (empathy, social cognition)
What are the main characteristics of estradiol?
Produced by ovaries, this hormone rises during follicular phase.
Crucial for the development and maintenance of reproductive tissues and influences secondary sex characteristics (breast and body fat).
In men – small amount produced by testes. Testosterone is converted to estradiol through the enzyme aromatase.
What are the main characteristics of progesterone?
Produced by corpus luteum in ovary after ovulation, preparing uterine lining for implantation. When pregnant, the placenta is the source of progesterone production.
In men and women - small amounts are produced by adrenal glands, having regulatory functions (metabolism, stress and other).
What are the main characteristics of cortisol?
Part of the glucocorticoids and plays role crucial in body stress response.
It is the “stress hormone”, helping the body cope with stressful situations (long term stress response).
What are the main characteristics of testosterone?
It is considered an androgen, primarily produced in the testes of men and small amount in the ovaries and adrenal glands.
Primary sex hormone of men, but plays an important role in women’s health too.
Libido, sexual function, bone health, muscle mass, mood, metabolism, …
Can also be related to psychosis, aggression, mood and cancer dev.
Ex: Male vs female gorillas
What are the main characteristics of vasopressin?
Know as the antidiuretic hormone, it is produced in hypothalamus and released by posterior pituitary gland.
Regulates water balance, blood pressure. and social behaviour.
High levels of vasopressin – social bonding and affiliation (pair bonding, parental behaviour, social recognition)
Name the hormones associated with parental behaviour.
- Prolactin
- Oxytocin
- Testosterone
- Estradiol
- Progesterone
- Cortisol
- Vasopressin
What is parental behavior?
Behaviours related to one’s offspring that contribute directly to the survival of fertilized eggs or offspring that have left the body of the female.
For infant survival, parental care is critical in many species and is thus critical for the reproductive success of the parents (their offspring reach maturity and produces offspring of their own).
We have maternal and paternal behaviour.
What is parental investment?
Extent to which parents compromise their ability to produce more offspring, in order to assist to current one.
Females tend to usually make the bigger investment (the choosier sex invest the most parental care).
What is the difference between precocial born offspring and altricial born offpspring?
Precocial: Born at advanced stage of development, requiring little or no parental intervention for survival.
Altricial: Born at early stage of development and quite helpless, requiring substantial parental care to survive.
Are humans precocial or altricial?
Humans are semiprecocials.
We are born at an intermediate state between the two. This type of offspring are born with some degree of development and independence but still require parental investment.
Ex: Human babies can thermoregulate (preterm babies cannot though).
What are the main maternal behaviours in dogs (dogs are atricial)?
- A couple of days before birth, dog builds a nest which her puppies will be born in.
- As each pup is born, mom licks of amniotic fluid, membranes and the anogenital region.
- Mom knows how to lay to expose her nipples to nurse
- She retrieves pups if they wander too far
- Shows aggression to intruders
What are the exceptions for paternal care in the animal kingdom?
Certain fish and bird species.
What is lactational amenorrhea?
The interruption of menstruation (postnatal infertility) that occurs when a woman is breastfeeding.
(Inadequate LH secretion inhibits the follicular phase, resulting in no ovulation)
Prolactin inhibits – GnrH inhibits – LH
How can you induce lactation without pregnancy?
Usually it involves hormonal therapy, breast stimulation and regular breast pumping or nursing to mimic the conditions that promote milk production.
What factors are associated with sex differences in parental behavior?
- Efforts in mating or parental behaviour (tradeoff between the two)
- Birth developmental stage of the offspring (some require the care of two adults)
- How males are able to meet offspring’s demands (avian species can both regurgitate but mammals only female can meet nutritional needs)
TRUE or FALSE.
All birds tend to have similar parental behaviour, as they have similar functioning of their endocrine system.
FALSE.
Some are biparental, chickens are female only and some could even be called adoptive (alloparental care), because they care for offspring that is not their own.
What hormone tends to induce maternal behaviour in female birds?
Prolactin.
Specifically, hens will display broody behaviour when in contact with the young of even another species when initiated by hormones.
TRUE or FALSE.
Sex hormones in birds peak during the time of egg laying (oviposition) and decrease to baseline prior to incubation.
TRUE.
If fertilized, prolactin concentrations begin to increase at time of egg laying and remain high during incubation
TRUE or FALSE.
Prolactin is lower in penguins and Florida scrub jays because they exhibit alloparental care.
FALSE.
Levels are increased in breeding individuals and helpers. It also correlates with the amount of care provided to the offspring.
It is also associated with elevated food consumptions by the breeding pair to support foraging.
What can be said about prolactin levels of avian species that hatch altricial species?
Their prolactin concentrations remain high throughout incubation and chick rearing, whereas precocial species only have high prolactin during incubation and it declines at time of hatching.
In mammals, prolactin used to be considered the critical hormone for maternal behaviour. What can be said now?
Estrogen concentrations around time of birth is critical for the onset of maternal behaviour. Estrogen rises with prolactin after birth.
What can be said about hormones in human pregnancy?
Pregnancy is accompanied by high concentration of estradiol and progesterone, followed by a drop in concentration of steroids after birth.
Oxytocin, cortisol (boosts immune system) and endorphins are also involved.
Drop in progesterone and estrogen after birth may contribute to postpartum depression.
How does sensitization work for rats who have never given birth?
In order to induce maternal behaviours in rats that have never given birth (nulliparous females), a blood transfusion from a new mother for 4 to 6 days is required for maternal behaviour to occur (sensitization).
So, not as directly inducible as birds.
What contributes to the maternal behaviour of aggression in dogs?
Hormones (progesterone) are needed but the presence of pups (in dogs) is also needed for the onset and expression of aggression.
So progesterone - aggression in females
Testosterone - aggression in males
What are some findings of questionnaires for parental behaviour in humans?
- New mothers rated infant-associated odours as more pleasant (body, urine, feces)
- Mother and fathers were more likely to identify shirts worn by their own infant
- Mothers and fathers could identify amniotic fluid associated with their own infant.
TRUE or FALSE.
Receptors for oxytocin and vasopressin are found within the olfactory system, which may help establish a mother’s attraction to her newborn infant’s odours.
(olfactory system - limbic hypothalamus system - ventral forebrain and brainstem)
TRUE.
Lesions along this pathway interfere with chemosensory processing and impedes maternal behaviour.
What hormone is associated with approach behaviours between infants in women?
Cortisol (higher cortisol, higher approach behaviours)
Cortisol may not induce directly, but may indirectly increase mother’s arousal. This association is only seen in first time mothers.
What hormone is associated with affectionate contact in parents?
Oxytocin (higher levels)
Specifically, women with the greatest increase in oxytocin as their pregnancy progresses show highest levels of maternal bonding.
In terms of behaviour in mice, what did fathers, expectant 1st time fathers and unmated single mice do when exposed to new-borns?
Unmated males - low parental behaviour
Expectant fathers - average levels of parenting
Fathers - high parental beh.
These behaviours are directly related to prolactin levels.
TRUE or FALSE.
Testosterone is always associated with low parental care in males and infanticide.
FALSE.
It is necessary for paternal behaviour in California mice. Castration reduced their paternal behaviour and replacement maintained high levels of paternal beh.
What hormones are involved in human paternal behaviour?
Similar to other mammals, testosterone, prolactin and cortisol.
Estradiol - higher in fathers
Test. - lower in fathers
Cortisol - lower in fathers
Fathers are more sympathetic to the crying of infants. Especially with higher prolactin and low testosterone.
How is the dopamine pathways involved in parental behaviour?
Interacting with babies is reinforcing. Feedback mechanism VTA and Nac associated with reward.
What do we know about the pregnant women’s brain?
- Down regulates stress response serving an adaptive purpose
- Higher ability to fend off threats and identify them
- There may be permanent changes in the brain of women after giving birth, that increases after each birth
What behaviour seems to have evolved from parental behaviour?
Affiliation, which involves motivation to approach and remain in close proximity with a conspecific.
In order to socially bond, social familiarity is required. What hormone is required for the development of social memory?
Oxytocin, those laking it do not develop social memory.
Oxytocin antagonists also directly block the formation of partner preferences.
For some, vasopressin plays a more important role for partner preference.
Exogenous administration of oxytocin and vasopressin facilitates pair bond formation in both sexes but what can be said about endogenous administration?
Prairie Voles
Endogenous oxytocin more important for pair bond formation in females and vasopressin for males.
TRUE or FALSE.
Individuals in couples display higher levels of oxytocin.
TRUE.
TRUE or FALSE.
Men with higher testosterone were less likely to be in long term relationships.
TRUE.
More likely to divorce, more likely in single men, more likely in polyamorous males
TRUE or FALSE.
Sex steroid hormones vary and affect tolerance of other same sex peers.
TRUE.
Less tolerance in the summer for close proximity and higher tolerance in the winter, as lower circulating sex steroids and lower concentrations.
What type of processes are methylation and histone modification?
Epigenetic processes
What is methylation?
A process of long-term gene silencing involving attaching methyl groups to cytosines in the promoter region of a gene.
How is mRNA synthesized?
A Transcription factor binds to a Promoter (or facilitatory region) allows an enzyme to begin the process. The sequence of RNA is determined by DNA.
What is homeostasis?
Ability to maintain optimal conditions in the body (hormones are critical).
Regulation of fluids, sodium, energy, temperature, …
What is a stressor?
It is something that disrupts homeostasis, which can affect the brain or behavior. The brain can perceive psychological factors as stressful and evoke a stress response.
It causes stress to the organism.
Stressors can be internal or external.
What are the different sources of stressors?
- Environmental: Temperature, noise, …
- Physiological: Insufficient food, water deprivation, …
- Psychological: Maltreatment, lack of control, …
What is the stress response?
A suite of physiological and behavioral responses to reestablish homeostasis.
There are two endocrine systems involved in the stress response. Which hormone is associated with the adrenal medulla and which on is associated with the adrenal cortex?
Medulla: Epinephrine (adrenaline)
Short term
Cortex: Glucocorticoids (cortisol)
Long term
Who is considered the founder of modern stress research and what did he observe?
Selye
He observed that epinephrine and glucocorticoids are released in response to virtually any stressor (HPA axis activates when faced with stressor and extreme cold)
Rats injected with ovarian hormone and with saline exhibited the same symptoms - peptic ulcers, adrenal hypertrophy, regression of immune organs - all this due to likely what common factor?
A physical response due to stress exposure (animal manipulation)
What are the 3 stages of General Adaptation System (Prolonged Stress Response)?
- Alarm Reaction Stage
Fight or flight activation leading to increased HR, awareness and energy
mobilization - Stage of Resistance
Body tries to cope with stressor and restore homeostasis, hormones and
physiological processes remain elevated - Stage of exhaustion
Body’s resources have become depleted, body has reduced ability to cope with
stressor. In some cases, this can even lead to death.
Ex: Rats exposed to low temperatures adapted around the 2 week mark but at around 2 months, they passed away (loss of adaptation)
What is stress and what are some limitations of the definition?
Stress is anything that throws your body out of homeostatic balance. It is the sum of all nonspecific effects of factors that increase energy consumption above base level. Stress can be adaptive in the short term but in the long term it can become maladaptive.
Limitations:
- Does not address of psychological factors can evoke a full physiological response
(can cause imbalance instead of restoring balance)
- Does not account for individual variation in perception of stressors
- Does not address how the same stimulus can stress one person but be pleasurable
to another
What is the human perception of stress?
- A condition in which individuals are aroused by aversive stimuli
- For an event to be deemed stressful, the individual must perceive it as aversive
- Individuals need to lack the perception that they have control over the aversive
stimuli
What is Allostasis and Allostatic Overload?
Allostasis are long term adaptations to maintain balance in the system.
Allostatic overload (load) is when long term adaptation become problems.
What has a stronger effect, epinephrine or norepinephrine?
Epinephrine, which is around 6x more potent but takes longer to be released.