Hormonal Communication- Exam 1 Flashcards
hormones
- chemical signals
- secreted by endocrine cells
- transmitted locally
- may reach all cells but will only affect those with the appropriate receptors
- can regulate lots of responses but is slower than the nervous system
pheromones
chemical signals released into the air that communicate information from organisms to the other and act through the olfactory system.
example: female menstruation cycles syncing up, female silkworm moths secrete pheromones
circulating hormones
endocrine to the bloodstream to target cells
local hormones
cell to cell either through paracrine or autocrine signaling
three pathway types
simple endocrine, neuroendocrine, and hormone cascade
the more steps, the more levels at which the response can be regulated
receptors are TM or cytoplasmic
TM: peptides, proteins, amines, oxytocin, LH, FSH, GH, glucagon, insulin, thyroxine, and epinephrine
cytoplasmic: steroids, estrogen, testosterone, progesterone, cortisol
all the parts of the endocrine system
pineal, hypothalamus, pituitary, thyroid, parathyroid, adrenal, pancreas, ovaries, testes
Precious Harry Potter Thinks Poorly About POT
Posterior pituitary
neuroendocrine pathway
hormones are synthesized in the hypothalamus and released from the pituitary, dependent on hypothalamic neurons
ADH action on the kidney’s reabsorption of water
stimulus: increased sweating which leads to high osmolarity
effect: ADH is released and thirst is felt so as to increase water intake which decreases blood osmolarity and brings it back to normal, ADH also increase kidney permeability causing it to absorb more water
consuming alcohol which contains ethanol, blocks the release of ADH, causing the person who consumes alcohol to become easily dehydrated
anterior pituitary
hormone cascade pathway
lots of hormones synthesized in the pituitary
tropic hormones regulate the activity of other endocrine glands
non-tropic hormones directly influence tissues that are not endocrine glands
secretion of many of these hormones is stimulated by specific releasing hormones released by the hypothalamus through portal blood vessels
Tropic hormones
FSH, LH, TSH, ACTH
testes/ovaries, thyroid, adrenal cortex
Non-tropic hormones
prolactin, MSH, endorphin
mammary glands. melanocytes/appetite, nociceptors in the brain
Non-tropic and tropic hormone
Growth hormone
liver, bones
Prolactin
mammalian females: stimulates breast development and milk secretion/production
mammalian males: helps regulate testes function
birds: regulates fat metabolism and reproduction
amphibians: regulates the timing of metamorphosis and acts as a larval growth hormone
fishes: regulates osmolarity
endorphins
body’s natural opiates
runner’s high- release fo hormones when stress and pain reach critical levels
morphine/opium/heroin mimic the effects of endorphins
growth hormone
lack in childhood: leads to pituitary dwarfism
excess is childhood: leads to gigantism
excess in adulthood: acromegaly
thyroid, TRH, TSH, and thyroxine
TRH= TSH releasing hormone and it is the first RH to be released from the hypothalamus
TSH= thyroid-stimulating hormone AKA thyrotropin
thyroxine: increases basal metabolic rate, exposure to cold stimulates the release of TRH
ultimate responses: upregulation of basal cell metabolism, stimulation fo fat breakdown, and protein synthesis
different forms of thyroxine
thyroid produces mostly t4
t3 has a higher affinity and is used more easily because it is iodinated
t4 can be converted to t3 by an enzyme
iodine deficiency means non-iodinated thyroxine is made, t4, and then there is no negative feedback to stop TRH causing goiter of hypothyroidism due to the accumulation of t4
hypothyroidism
iodine deficiency or inherited
adults: goiter, low metabolism, intolerance of cold, general mental and physical sluggishness
children: mental retardation, stunted growth, and cretinism
hyperthyroidism
Grave’s disease- an autoimmune disorder where antibody to TSH is made causing increased thyroxine production
bulging eyes, heat behind eyes, jumpy, all symptoms of abnormally high metabolism
adrenal glands
made of the adrenal medulla and cortex
adrenal medulla
produces amines epinephrine and norepinephrine, grows from the nervous system and remains under its direct control
adrenal cortex
produces cortisol and under the control of the anterior pituitary through adrenocorticotropin
use cholesterol to produce cortisol and cytoplasmic receptors used because the molecules in question are hydrophobic
epinephrine`
fight or flight, alpha and beta-adrenergic
norepinephrine
physiological regulation, alpha-adrenergic
catecholamines
epinephrine, norepinephrine
three types of G protein
s- stimulatory
i- inhibitory
q- precursor molecule
beta blockers
block epinephrine in beta-adrenergic receptors, and leave alpha receptors open for norepinephrine regulatory function to decrease fight-or-flight response by inactivating adenylyl cyclase
stress response
stimulus: stress
hypothalamus: CRH
anterior pituitary: ACTH
adrenal cortex: cortisol
Why is the cortisol response slower than epinephrine?
This is because epinephrine is a catecholamine that is emitted in the nervous system, and the nervous system responds more quickly to stimuli than the endocrine system
short term stress response
adrenal medulla, epinephrine and norepinephrine
- increased blood glucose
- increased blood pressure
- increased breathing rate
- increased metabolic rate
- change in the blood flow pattern, increased blood flow leading to alertness, decreased blood flow to kidneys and digestive system
long-term stress
adrenal cortex, HPA axis
- proteins and fats are broken down and converted to glucose which may lead to increased blood sugar
- immune system is suppressed
sex steroids
male: androgens, especially testosterone
female: estrogen and progesterone\
in fetal development: no androgen in the womb means female
sex steroid pathway
hypothalamus: GnRH
anterior pituitary: LH and FSH
gonads: respective sex steroids
unintentional experiments
bodybuilders, Klinefelter’s, Castrati
glucose levels
beta-cells: release insulin
alpha cells: release glucagon
after a meal, insulin rises, then glucagon rises to maintain homeostasis
diabetes mellitus
type 1 lack of insulin
type 2 lack of insulin receptors
rhythmic hormones
cortisol, growth hormone, and melatonin
extracellular hormone degradation
- degradation by hormones in the liver, blood, and lymph or converted into an inactive form
- removal from blood kidneys into the urine
half-life of epinephrine is 1-3 days
cortisol and thyroxine half-life is on the order of days
