Lecture 26 -- Endocrine System III Flashcards
LO1: relate steroid hormone structure to that of cholesterol. Give examples.
name all the steroid hormones and where they are produced
adrenal cortex:
- mineralocorticoids (aldosterone)
- glucocorticoids (cortisol)
- androgens
gonads:
- testosterone
- estrogen
LO1: relate steroid hormone structure to that of cholesterol. Give examples.
how are steroid hormones synthesized?
what do all the steroid hormones have in common?
how do the steroid hormones differ?
synthesized from cholesterol
they all have a 4-ringed steroid backbone
they differ in the functional groups attached to the 4-ringed steroid backbone
LO2: how are steroid hormones transported in blood?
steroids are hydrophobic –> must bind to hydrophilic transport proteins
LO2: how are steroid hormones transported in blood?
what are examples of the hydrophilic transport proteins?
albumins and globulins –> synthesized by liver
LO2: how are steroid hormones transported in blood?
what do the hydrophilic transport proteins do?
increase steroid half lives
protect steroids from:
- enzymes
- being filtered out of blood by kidneys
LO3: describe target cell stimulation by steroid-H:
how do most steroids stimulate target cells? What do they do?
steroids = hydrophobic
pass thru cell mb directly to nucleus
genomic effects –> affects transcription
LO3: describe target cell stimulation by steroid-H:
exception to this rule
glucocorticoids –> bind to cytosol instead
LH –> non-steroid but is also lipid soluble and can enter cell as well
LO4: give examples of hormones w/ monoamine structure and indicate their amino acid precursor
what are monoamines made of?
amino acids
LO4: give examples of hormones w/ monoamine structure and indicate their amino acid precursor
examples of monoamines and their aa precursor
catecholamines (synthesized from tyrosine):
- dopamine –> synthesized from tyrosine
- epinephrine –> synthesized from tyrosine
- norepinephrine –> synthesized from tyrosine
melatonin –> synthesized from tryptophan
thyroid hormone (TH) –> synthesized from tyrosine
- thyroxine (T4) –> synthesized from tyrosine –> lipid soluble
- triiodothyronine (T3) –> synthesized from tyrosine
LO5: give examples of peptide hormones:
what are they made of? How are they synthesized?
made up chains of amino acids
synthesized the same way as any other protein
LO5: give examples of peptide hormones:
give examples of peptide hormones and where they are produced:
releasing hormone (RH) and inhibiting hormone (IH) –> produced by hypothalamus
most hormones of anterior pituitary gland are polypeptides or glycoproteins
insulin
growth hormone
oxytocin
antidiuretic hormone (ADH)
LO6: describe the following steps applying to peptide-H and monoamines:
1) peptide-H and monoamines synthesized and stored in secretory vesicles until stimulus is received
2) transportation: peptide-H and monoamines are hydrophilic –> travel freely in blood
3) binding and effects: hormones can’t cross membrane so bind to cell-surface receptors –> signal transduction pathway (2nd messengers – CAMP, DAG, IP3)
hormone doesn’t always employ the same 2nd messenger
LO7: summarize the cyclic AMP signaling pathway
1) hormone binds to receptor
2) activates G protein –> activates adenylate cyclase
3) activate adenylate cyclase converts ATP into cAMP
cAMP gets broken down by phosphodiesterase (PDE)
4) cAMP activates protein kinase (PK) –> PK attaches phosphates to other molecules
5) PK phosphorylates enzymes (activates/deactivates)
6) altered protein (enzyme) –> causes cell response
LO7: summarize the cyclic AMP signaling pathway
example of glucagon:
cAMP leads to activation of enzymes that hydrolyze glycogen stored in cell
LO8: summarize the DAG-IP3 signaling pathway
1) hormone binds to receptor –> activates G protein
2) activated G-protein binds to and activates phospholipase (PLC) enzyme
3) phospholipase splits a membrane phospholipid into 2 fragments –> DAG and IP3 (2nd messengers)
LO8: summarize the DAG-IP3 signaling pathway
what does the pathway do?
can open Ca channels in the plasma mb or in the ER
Ca2+ binds to calcium-dependent cytoplasmic enzymes that alter cell metabolism
LO9: identify the 3 types of stimuli for hormone secretion
are hormones secreted at steady rates?
do they have constant levels in bloodstream throughout the day?
no
no
LO9: identify the 3 types of stimuli for hormone secretion
neural (describe)
nerve fibers supply some endocrine glands and elicit the release of their hormones
LO9: identify the 3 types of stimuli for hormone secretion
humoral (describe)
blood-borne stimuli
LO9: identify the 3 types of stimuli for hormone secretion
hormonal (describe)
1 hormone stimulates the secretion of another hormone
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone receptors:
hormone receptors are ___ or ___ located on the ___, in the ___, or in the ___
proteins or glycoproteins
located on the plasma mb, in the cytoplasmic, or in the nucleus
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone receptors:
not all cells express the same ___
receptors
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone receptors:
most cells are sensitive to more than one ___
hormone
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone receptors:
hormone stimulate only those cells that have ___ for them (their target cells)
receptors
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone receptors:
the same type of ___ may be located on cells in different body tissues, and trigger somewhat ___ responses
receptor
different
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone receptors:
receptors exhibit ___ and ___
specificity
saturation
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone receptors:
define specificity
the receptor for one hormone will not bind other hormones
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone receptors:
define saturation
condition in which all the receptor molecules are occupied by hormone molecules – adding more hormone cannot produce any greater effect
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone clearance:
most hormones are taken up and degraded by the ___ and ___ and then excreted in the ___ or ___
liver –> bile
kidneys –> urine
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone clearance:
some hormones are degraded by their ___
target cells
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone clearance:
define metabolic clearance rate (MCR):
the rate of hormonal removal
LO9: identify the 3 types of stimuli for hormone secretion
key ideas and concepts about hormone clearance:
define half life (t 1/2):
the length of time required to clear 50% of the hormone from the blood
LO10: explain how target cells regulate their sensitivity to circulating hormones:
target cells can adjust their sensitivity to a hormone by changing the number of receptors for it
up-regulation – increase receptor density –> increase sensitivity –> stronger response
- ex. late pregnancy –> uterus produces oxytocin receptors
down-regulation – decrease receptor density –> decrease sensitivity –> diminished response
- ex. in response to long-term exposure to a high hormone
LO11: differentiate the types of hormone-hormone interactions:
antagonistic – one opposes the other
additive – synergistic hormones work together. effects may be additive or complementary
permissive – one hormone is required before target cell can respond to another hormone
LO12: discuss how the body adapts to stress thru its endocrine and sympathetic NS:
define stress
situation that upsets homeostasis
physical or emotional causes
LO12: discuss how the body adapts to stress thru its endocrine and sympathetic NS:
how does the body respond to stress?
stress response or general adaptation syndrome (GAS)
mediated by endocrine and sympathetic NS
increase cortisol and epinephrine
LO12: discuss how the body adapts to stress thru its endocrine and sympathetic NS:
describe 3 stages of GAS:
stage 1 is called the ___
how does it occur?
what does it do?
what is it mediated by?
what are the hormones involved?
alarm reaction – “fight or flight”
stressor upsets homeostasis or cellular balance
increased mental alertness
mediate mainly by sympathetic stimulation
mostly epinephrine, some norepinephrine
ge LO12: discuss how the body adapts to stress thru its endocrine and sympathetic NS:
describe 3 stages of GAS:
stage 2 is called the ___
what is it marked by?
what is the main priority?
what happens?
what hormone gets released and what does it do?
stage of resistance or adaptation
body fights back by adjusting to stress
glycogen reserves become exhausted.
priority –> provide alternative fuels for metabolism
gluconeogenesis occurs in liver –> breakdown of fat and protein
cortisol –> inhibits glucose uptake by most organs –> glucose-sparing effect –> saves glucose for brain
LO12: discuss how the body adapts to stress thru its endocrine and sympathetic NS:
describe 3 stages of GAS:
stage 3 is called the ___
what is it marked by?
when does stage of exhaustion set in?
what is the result of stage of exhaustion?
describe the energy sources…
stage of exhaustion
lack of adaptation response
sets in when fat is depleted (months)
stress overwhelms homeostasis –> rapid decline –> death
no more glycogen –> no more fat –> body relies on protein breakdown –>
difficult to maintain glucose homeostasis –> infections
failure to maintain adequate fluid and electrolyte balance
LO13: infer the type of short-distance signaling that chemicals can use for communication
what are the 3 types of signaling?
paracrine –> signal to nearby cells in same tissue or organ
contact-dependent –> must be in contact to signal, (e.g. gap junctions)
autocrine –> signal stimulates same cell that secretes them
LO13: infer the type of short-distance signaling that chemicals can use for communication
T or F:
single chemical can be considered a hormone, paracrine, autocrine, or neurotransmitter depending on location and circumstance
true
LO14: explain what eicosanoids are and how they are produced
eicosanoids are…
they are produced by…
signaling molecules made by oxidation of FA
20-carbon backbones derived from the FA arachidonic acid
LO14: explain what eicosanoids are and how they are produced
give examples of eicosanoids
a type of eicosanoid is prostanoids
3 types of prostanoids:
- prostaglandins
- prostacyclin
- thromboxane
a type of eicosanoid is leukotrienes:
- leukotrienes help regulate bronchoconstriction and mucus secretion
LO15: describe the physiological roles of prostanoids in:
GI mucosa
NSAID: COX-1
gastric protection
side effects (COX inhibition):
- peptic ulcers
- GI bleeding
LO15: describe the physiological roles of prostanoids in:
kidney
NSAID: COX-1&2
greater sodium and water excretion
said effects (COX inhibition):
- Na and water retention
- hypertension
- kidney injury
LO15: describe the physiological roles of prostanoids in:
cardiovascular
NSAID: COX-1&2
COX2 > COX1 inhibition:
- stroke
- myocardial infarction
