Endocrine 1: Hormonal Signals Flashcards
the endocrine system is a complex network consisting of ___, ___ and___
glands; hormones; effect on target
t/f glands secrete specific things based on specific stimulus
t
do endocrine glands have ducts?
no
endocrine glands empty directly into ___
blood
what are hormones? where are they produced and secreted?
a variety of chemical signalling molecules produced by the endocrine cells or glands and secreted into the blood
t/f hormones can travel in the bloodstream to target cells that are both nearby or far away
t
hormones act on specific receptors either on the ___ or __
cell membrane or inside the cell
what is the major signalling pathway in the endocrine system?
classical endocrine signalling
what are the 4 types of signalling in the endocrine system?
- classical endocrine
- neuroendocrine
- autocrine regulation
- paracrine regulation
what happens in classic endocrine signalling?
hormone leaves endocrine cell and travels through the blood to a target cell anywhere in the body
what happens in neuroendocrine signalling?
neurohormones are secreted from neuroendocrine cells and travel through the blood to a target cell anywhere in the body
what happens in autocrine regulation?
the hormone that is released acts on the same cell that released it
what happens in paracrine regulation?
released hormone acts on a nearby cell
the main function of many hormones is to stimulate the release of ____
other hormones
what are the 2 ways hormones maintain homeostasis?
metabolism and osmoregulation
what are the 6 main functions of hormones?
- stimulate other hormones
- homeostasis
- coordinate develpoment
- regulate groth and morphology
- reproduction
- behavioural and social interaction
t/f adipocytes have important endocrine functions
t
which glands only have endocrine function?
pituitary and thyroid
which glands have endocrine and exocrine functions?
pancreas
which part of pancreas secretion is Eno/exo ?
endocrine : insulin
exocrine: digestive function
what are the 3 major types of stimuli in the endocrine system?
- humoral
- neural
- hormonal
what is humeral stimulus?
control of hormone release based on changes in extracellular fluids (eg Ions, glucose levels)
explain how the parathyroid glands are involved in humeral stimulus when blood Ca is low
parathyroid senses low Ca and secreted PTH which acts to raise Ca
what is neural stimulus?
when the nervous system directly stimulates the endocrine glands to release hormones (adrenaline and noradrenaline in response to stress)
how does the neural stimulation of the endocrine system work?
the preganglion sympathetic fibers from the spinal cord stimulated the adrenal medulla cells causing the adrenal gland to release catecholamines into the bloodstream
what is hormonal stimulation?
release of hormone in response to another hormones
the hypothalamus secreted hormones that stimulates hormone release from the ___, which stimulates hormone release from ___
anterior pituitary; other endocrine glands (such as gonads, thyroid, adrenal cortex)
amino acid derivative hormones are derived form ___
tyrosine
amino acid derivative hormones are released from the ___ and __
thyroid and adrenal medula
what are 2 examples of amino acid derivative hormones?
epinephrine and T4/T3
peptide and protein hormones are made of
peptides
peptide hormone are secreted from the __ and __ _
anterior pituitary and pancreas
what are 2 examples of peptide hormones?
gastrin and insulin
peptide hormones mostly bind to what type of receptor?
cell surface
steroid hormones are derived from ___
cholesterol
steroid hormones are secreted from the __ and __
adrenal cortex and gonads
2 examples of steroid hormones
testosterone and oestrogen
what are tropic hormones?
hormones secreted to act on endocrine cells which will then secrete their own (non-tropic) hormones
what are tropic hormones?
secreted by the endocrine cells and then act directly on effector
what is the function tropic hormones/
regulate production and secretion of hormones by other endcrine cells
2 examples of tropic hormones
FSH and TSH
what is the function of non-tropic hormones?
regulate cellular functions ranging from autophagy and metabolism atoms proliferation and cell death
give 2 examples of non-tropic hormones
oestrogen and vasopressin (ADH)
wate soluble hormones bind to ___ receptor and activate ___(quickly or slowly) and have _____term effects
cell surface; quickly; long
MOA of water soluble hormones
bind to cell surface receptor, second messengers activate or deactivate enzyme that produce cellular response
lipophilic hormones bind to ___ receptors and act ____ and have ____term effects
cytoplasmic and nucleic; slowly; long
MOA for lipophilic hormones (action in nuclear)
- cross membrane
- bind to cytosolic receptor (kept inactive by heat shock proteins)
- HSP released, conformation change of receptor
- receptor and hormone enter the nuclei
- bind to DNA and initiate transcription
- mRNA enters cytoplasm and new protein is made
what is the most common receptor type in the endocrine system?
GPCR
how does hormonal signalling by GPCRs work?
binding activates G protein (GI) which activates adenyl cyclase to make cAMP which activates PKA to phosphorylate proteins (enzymes) to carry out response
what happens when an activated G protein activates PLC?
turns PIP2 into IP3 and DAG, IP3 opens Ca channels which acts as a second messenger to activate various proteins with different responses
___% of all drugs are GPCR targeting
50
2 examples og GPRC targeting drugs
sumatriptan (migraine) and oxytocin (induce labor)
thyroid hormones act very much like steroid hormones except that their receptor are generally always ___
already in the nucleus
thyroid hormones most likely cross the cell membrane by ___ but there may also be ___ involves
difusion; carrier mediated transport
cell surface receptors can be ___ and __ in response to prolonged hormone release / levels
internalized and degraded
most endocrine feedback loops are __, meaning ___
negative; meaning when target tissues make more of the desired product, the endocrine uncharge of making the hormone to stimulate the production slows down on hormone release
an increase in plasma glucose causes release of what hormone?
insulin
