Endocrinology Exam 1

endocrine definition

distance between site(s) of secretion and action

hormone definition

chemical secreted in trace amounts by one or more cells, where it modulates a specific biochemical or physiological responses

tropic hormone

hormone that targets another endocrine tissue

gland

an organ which can secrete chemical substances for use within the body or into surroundings

what other structures can secrete hormones

single endocrine cells

T/F all glands secrete hormones, give an example if false

false- salivary glands are glands that don’t secrete a hormone

endocrine function

through blood

liver endocrine function

insulin-like growth factor into bloodstream

pancreas endocrine function

pancreatic islet cells into bloodstream

exocrine function

through a duct

liver exocrine function

bile thru bile duct to gallbladder

pancreas exocrine function

acinar cells to pancreatic duct

goal of homeostasis

maintain internal environement despite changes in internal/external conditions

homeostatis in terms of hormones

hormone is released in response to internal or external stimulus/change in the environment; once response is met, hormone secretion has to be inhibited, typically by a negative feedback loop

message amplification

hormones secreted at low concentration still powerful physiology effects

negative feedback

the effect of a hormone reduces further secretion of that hormone, maintaining balance

hormone main functions

homeostasis, growth/developement, energy balance and metabolism, reproduction, sleep/wake cycle, mood, responses to external stimuli

main hormones involved in homeostasis

insulin, glucagon, aldosterone, cortisol, parathyroid hormone, thyroid hormone

main hormones involved with growth and development

growth hormone, thyroid hormone, testosterone, estrogen, progesterone

main hormones involved in energy balance and metabolism

thyroid hormone, cortisol, glucagon, insulin, ghrelin

main hormones involved in reproduction

estrogen, progestoerone, testosterone, luteinizing hormone, oxytocin, prolactin

main hormone involved in sleep/wake cycles

melatonin

main hormones involved in mood

adrenaline/epinephrine, cortisol, oxytocin

main hormones involved in responses to external stimuli

adrenaline/epinephrine, gastrin, cholecystokinin, ghrelin

hormone mode of action- endocrine

uses the circulatory system to transport the ligand to the target cells

hormone modes of action- paracrine

ligand acts on nearby cells

hormone modes of action- autocrine

ligand acts on the secretory cell (act on itself)

neuron signals are an example of what hormone mode of action

paracrine

hormone mechanism of release- humoral

response from change in composition of fluid

hormone mechanisms of release- neural

nerve communication

hormone mechanisms of release- hormonal

stimulated by other hormones

types of hormones

amino acid derivatives, small peptides, large peptides, steroid hormones, modified fatty acids, vitamin derivatives

amino acid derivative hormones

dopamine, norepinephrine, epinephrine, serotonin, thyroid hormone

amino acid derivatives speed of action

act quick

small peptides hormones

gonadotropin-releasing hormone, somatostatin, vasopressin

large peptide hormones

insulin, lutenizing hormone

steroid hormones

cortisol, aldosterone, testosterone, progesterone/estrogen, vitamin D3

what are steroid hormones made of

fat

steroid hormone mode of action

long mode of action

modified fatty acid hormones

eicosanoids and prostaglandins

vitamin derivative hormones

retinoids (vitamin A), vitamin D

when are amino acid derivatives and peptide hormones synthesized

transcription and translation

amino acid derivatives and peptide hormone note

one gene can produce several different product

ways on gene can produce several different products

alternative splicing and post-translation regulation

where in the cell are amino acid derivates and peptide hormones made

during transcription in nucleus, translation in the ER, proccessing in the ER to the golgi, packaging in the golgi to secretory vesicles to target)

how do they know where to go

preprohormone and prohormone stages before being a fully active protrein/hormone

what is regulated secretion

the cell stores hormone in secretory granules and then releases them when stimulated

what is constitutive secretion

the cell does not store hormone, but secretes it from secretory vesicles as it is synthesized

what can cause constitutive secreation

activation is stuck at level of receptor

what are many neurotransmitters

enzymatically modified amino acids

neurochemically active amino acids

glutamate, GABA

glutamate

excitatory

GABA

inhibitory

neurochemically active amino acids speed of action

fast excititory/inhibitory transmission

monoamines formation

one amino acid connected to an aromatic ring

monoamines speed of action

slower- modulation of networks

monoamine hormones

dopamine, norepinephrine/noradrenaline, epinephrine, serotonin

what are catecholamines

water soluble hormones and neurotransmitters

catecholamines hormones

dopamine, norepinephrine/noradrenaline, epinephrine, serotonin

neuromodualtor peptides speed of action

slower, modulation of circuit function

neuromodulator peptide hormones

canabinoid, oxytocin, orexin, CART, etc

why is acetylcholine special

acetylcholine is synthesized via emzymatic modification of precursors acetyl-CoA and choline

synthesis of steroid homones stimulated by

tropic hormones

where are steroid hormones produced

adrenal cortex and gonads

what is the precursor for steroid hormones

cholesterol

what are the 3 parts of the adrenal cortex

zona glomerulosa, zona fasiculata, zona reticularis

zona glomerulosa synthesizes

mineralocorticoids

function of minerocorticoids

regulate electrolyte and fluid balance

mineralocorticoid hormone

aldosterone

zona fasiculata synthesizes

glucocorticoids

what is the make up of glucocorticoids

glucose, cortex, steroid

glucocorticoids function

role in glucose metabolism, regulates immune response

glucocorticoid hormone(s)

cortisol, corticosterone, cortisone

zona reticularis synthesizes

sex steroid hormones

the adrenal medulla synthesizes

catecholamines

mineralocorticoids and glucocorticoids are

types of corticosteroids

modified fatty acids (eicosanoids) are derived from

arachidonic acid

modified fatty acids/eicosanoids method of action

autocrine and paracrine

modified fatty acids/eicosanoids mainly deal with

inflammation

what class do modified fatty acids/eicosanoids also include

prostaglandins

modified fatty acids are synthesized by

phospholipase A2

what step is the rate limiting step for modified fatty acid synthesization

first step (phospholipase A2)

what type of receptors do protein based hormones have

cell surface receptors

what type of receptors do steroid hormones have

intracellular nuclear protein receptors

what are the two main domains of receptors

ligand binding domain (extracellular) and effector domain (intracellular)

receptors are subject to

removal/inactivation

cell surface receptors has how many domains

3

what are the three domains

ligand binding domain (extracellular), membrane spanning domain, effector domain (intracellular)

ligand binding and effector domain both regulate what

gene expression

types of cell surface receptors

g-protein coupled receptors, tyrosine kinase receptors, ligand gated ion channels

g-protein coupled receptors

7 transmembrane domains, act via g-protein complex, engage in second messengers

what subunit of the g-protein complex dissociates and moves to another nearby protein

alpha

what are the other subunits of the g-protein complex

beta, gamma

where does the receptor act for g-protein coupled receptors

guanine nucleotide exchange factor

Gα_s function

stimulate cAMP

Gα_i function

inhibits cAMP

Gα_q function

increase calcium

tyrosine kinase receptors

single membrane spanning receptors, could dimerize upon ligand binding

what is the first step of tyrosine kinase receptors

phosphorylation of tyrosine

exception to the single membrane rule

insulin receptor and insulin-growth factor 1 receptor both dimerize and have 2 membranes