test 3 Flashcards
organs whose primary
function is to release
hormones
glands
how are hormones similar to neurotransmitters?
- they interact with receptors
which, in turn, cause a series
of events to occur within the
target cell - some are packaged into vesicles
and are released by neurons as a
result of action potentials
how are hormones different from neurotransmitters?
- released into the circulatory system (as opposed to synapse)
- meant to travel very long distances i.e. in the blood stream
- hormones are in the circulation for a much longer time period and have a slower onset of action and slower offset of function
what gland is referred to as the master gland?
pituitary gland
what kind of hormones does the pituitary gland release?
tropic hormones
what are tropic hormones?
hormones that work on other endocrine glands
what are the two glands that make up the pituitary gland?
anterior pituitary and posterior pituitary
what’s the “master” of the master gland
hypothalamus
which parts of the hypothalamus communicate with the posterior pituitary gland?
paraventricular nucleus and supraoptic nucleus
what hormones are synthesized by the hypothalamus?
oxytocin and vasopressin
in the posterior pituitary axon terminals
containing hormones release them where?
directly into the blood stream
how do oxytocin and vasopressin travel from the hypothalamus into the posterior pituitary
axonal transport down the pituitary stalk
what are oxytocin and vasopressin released into general circulation by?
terminal buttons in the posterior pituitary
what is oxytocin involved in?
muscle contractions and social behaviors
what muscle contractions is oxytocin involved in?
- uterine contractions
- milk ejection
- sexual intercourse (orgasm)
what social behaviors is oxytocin involved in
- maternal behavior
- pair-bonding
what are hormones released by the anterior pituitary gland involved in?
- organizational (developmental) and activational aspects of sexual behavior
- stress response
- growth
how does the path of the hormones from the hypothalamus to the gland differ between the anterior and posterior pituitary?
posterior - travels to the gland and hormones are released in the gland into the bloodstream
anterior - hypothalamus releases hormones that then travel to the gland and cause the anterior pituitary to release other hormones that go into the bloodstream
difference between hormones released by the hypothalamus into the posterior vs anterior pituitary
posterior - “ready to go” hormones
anterior - hormone releasing hormones
other name for “hormone releasing hormones”
releasing factors
what behavior does the hypothalamus appear to be critical for and how do we know
aggressive behavior, proven by “sham rage”
what behavior does the hypothalamus appear to be critical for and how do we know that?
aggressive behavior, proven by “sham rage”
what’s an affective attack? (cat)
electrical stimulation of specific regions of the hypothalamus lead to the cat expressing anger at nothing
two ways in which the
hypothalamus activates the
adrenal gland
neural and hormonal
two portions of the adrenal glands
cortex and medulla
what does the cortex of the adrenal glands secrete?
cortisol, androgens (testosterone) and estrogens (estrogen)
what does the medulla of the adrenal glands secrete?
epinephrine and norepinephrine
what’s the neural stress response?
activates sympathetic nervous system (via a chain of neurons that ends in the adrenal medulla) releasing epinephrine and norepinephrine
what’s the hormonal stress response? (step by step process)
hypothalamus releases CRH (corticotropin-releasing hormone)
CRH stimulates release of ACTH (adrenocorticotropin hormone) into anterior pituitary gland
ACTH stimulates the adrenal cortex to release cortisol
neuroendocrine function is the interaction between:
neurons, glands, hormones and their receptors on organs including the brain
organs whose primary function is to release hormones
glands
effects of epinephrine and norepinephrine
increased heart rate and blood pressure
immediate response
effects of cortisol
increases blood sugar level
delayed response
body uses resources for the immediate response to threat and cortisol helps liberate energy to return the body back to homeostasis
short vs long term effects of stress
short term - adaptive (good)
long term - bad
cortisol’s effects on testosterone
high cortisol -> low testosterone
what are the gonadal hormones
androgen (testosterone), estrogen, and progesterone
chronic stress effects on health
ovaries - decreased levels of gonadal hormones
testis - testicular atrophy, decreased levels of hormones of the gonadal axis
immune system - basal immunosuppression and decreased immune responsiveness
adrenal gland - elevated basal levels of glucocorticoids (cortisol), sluggish response to and recovery from stress
which pituitary gland is relevant to sexual behavior
anterior pituitary gland
hypothalamus as relevant to sexual behavior (step by step process)
hypothalamus releases gonadotropin-releasing hormone (GRH)
GRH causes the anterior pituitary to release gonadotropins
gonadotropins act on the gonads (ovaries, testes)
the gonads release androgens (e.g. testosterone) and estrogens (e.g. estradiol)
hormones released by gonads in male vs female
both male and female gonads release these hormones but:
males: androgens > estrogens
females: estrogens > androgens
pattern of hormone release male vs female
male - “steady” release of gonadotropin stimulating hormone
female - cyclical pattern (menstrual cycle)
how are the primordial gonads different at conception?
they’re not, they start out the same
what’s the default sex
female
how does the default female turn into male?
Y chromosome causes the production of SRY (sex determining region Y) protein which causes the medulla of the primordial gonad to develop into a testes
testes begin to secrete the hormone testosterone and mullerian-inhibiting substance
starting reproductive ducts male vs female
the same, everybody starts out with both sets
wolffian system
can develop into male ducts (seminal vesicles and vascular deferens)
mullerian system
can develop into female ducts (uterus and fallopian tubes)
presence vs lack of mullerian-inhibiting substance and testosterone
presence - testosterone causes the wolffian system to develop and mullerian-inhibiting substance causes the mullerian system to degenerate
absence - mullerian system develops into female reproductive ducts and the wolffian system fails to develop
what is the role of the ovaries during development?
they don’t have one, they’re inactive during development
how is the hypothalamus “masculinized”?
by the hormone estradiol
what hormone can testosterone be converted into?
estradiol
ovaries in terms of estradiol during development
ovaries (basically) don’t secrete estradiol during development
how come the estradiol from the mother does not masculinize every brain?
alpha-fetoprotein binds to estradiol and prevents it from reaching the brain because it cannot the blood-brain barrier
alpha fetoprotein on estradiol vs testosterone
it binds to estradiol but not testosterone
so testosterone can make it’s way to the brain and then be converted into estradiol
area of the brain in males that facilitates sexual behavior
medial preoptic area of the hypothalamus (mPOA)
organizational vs activational effects of hormones
organizational - how the different sexes are “created”
activational - how the sexes “sex” (sexual behavior)
hormones’ effect on female sexual behavior (rats)
female rats without gonadal hormones are not receptive to males at any time
area of the brain in females that facilitates sexual behavior
ventromedial nucleus
area of the hypothalamus related to feeding behavior
arcuate nucleus
neurons that stimulate feeding behavior
Agrp/Npy
neurons that suppress feeding behavior
Pomc
excites Agrp/Npy neurons
ghrelin
excites Pomc neurons
leptin
what was wrong with the obese mouse?
failure to make and release leptin
what was wrong with the diabetic mouse?
failure to express leptin (receptors)
what’s an EEG
averages the activity of hundreds to thousands of individual neurons
what’s an EEG
averages the activity of hundreds to thousands of individual neurons
what’s an EOG
recordings of eye movement
what’s a EMG
recordings of muscle tension
what are the 2 major classes of sleep?
slow wave and rem sleep
characteristics of stage 1 sleep
presence of alpha rhythm (8-12 Hz)
characteristics of stage 2 sleep
presence of sleep spindles and K complex
characteristics of stage 3 sleep
presence of delta rhythm (1 Hz)
characteristics of stage 4 sleep
majority in delta rhythm (1 Hz)
why is REM sleep also called paradoxical sleep?
EEG pattern during REM is identical to that of an awake state
how are we able to tell if a person is in REM sleep if their EEG looks like they’re awake?
complete loss of muscle tone (EMG) and rapid eye movement (EOG)
lack of what causes narcolepsy?
hypocretin
what area of the hypothalamus releases hypocretin
lateral hypothalamus
what does activating hypocretin during sleep do?
promote transition to wakefulness
