Block 3 - Endo Flashcards
Mediators that are neurotransmitters and hormones
norepi , epi, oxytocin
two types of local hormones
paracrine / autocrine
where are lipid-soluble hormones synthesized?
liver
hormone secretion is controlled by
signals of nervous system and chemical changes
What hormone stimulates the release of cortisol from the adrenal coretex?
where is is secreted from?
ACTH
anterior pituitary
Define positive and negative feedback
positive-reinforces
negative-reverses
3 major groups of hormones
protein and peptides / steroid / tyrosine derivatives
hormones can be classified by
solubility / gland of secretion / function
majority of hormones in the body are
protein / polypeptides
protein / polypeptides have what type of solubility?
water-soluble
hGH and prolactin are what type of hormones
water soluble, PROTEIN hormones
thyrotropin releasing hormone (TRH) is what type of hormone
water soluble, POLYPEPTIDE hormone
What hormones are released from hypothalamus?
GHRH / GHIH / TRH / CRH / GRH
what hormones are released from the anterior pituitary gland?
hGH / TRH / ACTH / (FSH / LH) / prolactin
What hormones are released from the posterior pituitary gland?
ADH / oxytocin
what does TRH stimulate and what does it do
thyrotropin hormone and prolactin;
synthesis/secretion of thyroid hormones (prolactin: milk production)
what does CRH stimulate and what does it do
adrenocorticotropin hormone: syn / sec of adrenocortical steroids
what does GHRH / GHIH stimulate and what does it do
stimulates release of hGH and inhibits hGH (protein synthesis and growth of most cells)
what does GRH stimulate and what does it do
causes releases luteinizing hormone and follicle stimulating hormone
luteinizing: testosterone / estrogen and progesterone production
follicle stimulating: growth of follicles / maturation of sperm
somatotropin and somatostatin are what two hormones
GHRH / GHIH - released by hypothalamus
what hormone is secreted by the thyroid
calcitonin - promotes deposition of calcium into bones to DECREASE serum calcium levels
what hormone is secreted by the parathyroid glands
parathyroid hormone; INCREASES calcium absorption by the guy and kidneys, break down bone matrix to increase serum calcium
hormones released by pancreas
insulin and glucagon
insulin-high glucose level to bring glucose in cells
glucagon-low glucose level
hormones released by plancentas
human chorionic gonadotropin hormone: growth of corpus luteum and secretion of estrogen and progesterone
human somatomammotropin - dev of fetal tissues; enlargement of mothers breasts
hormones of kidneys
renin: catalyzes conversion of angiotensinogen and angiotensin
EPO: increases RBC production
hormones of the heart
atrial-natriuretic hormone (ANP) increases sodium by kidneys, reduce blood pressure
hormones of the stomach
gastrin - HCl secretion by PARIETAL CELLS to aid digestion
hormones of small intestines
secretin: pancreas to bicarbonate
cholecystokinin: stimulates gallbladder contraction; release of pancreatic enzymes
hormones of the adipocytes
leptin: inhibits appetite, stimulates thermogenesis
steroid hormones are what soluble
lipid soluble
steroid hormones have to have what?
transport proteins
where do steroid hormones bind?
inside the cell
how much of a concentration of steroid hormone are stored?
little concentrations of these are stored
what steroid hormone is released by kidneys
calcitriol (1,25 dihydroxycholecaliferol): inc. intestinal absorption
what adrenal cortex hormones
cortisol: multiple functions-controlling metabolisms; anti-inflammatory
aldosterone: inc. renal sodium ABSORPTION and K/H ion secretion
what hormones are from testes
testosterone: promotes dev. of male repro system
what hormones are from ovaries
estrogen: promotes growth/dev of female repro syst, breasts, secondary characteristics
progesterone: helps to produce “uterine milk”-nourishes growing embryo; helps dev secretory apparatus of breasts
what are the tyrosine derivative hormone
T3/T4 ; adrenal medullary hormones (CATECHOLAMINES) ; dopamine
what is the prolactin inhibiting hormone
dopamine
what are the catecholamines
norepinephrine / epinephrine
what tyrosine hormones are released by hypothalamus
prolactin inhibiting hormone (DOPAMINE)
what tyrosine derivative hormones are water soluble / what are lipid soluble
Dopamine / Epinephrine / Norepinephrine (water soluble)
T3/T4 (lipid soluble-bound to transport proteins)
Which thyroid hormone is the active form
Which is the precursor
t3 is active / t4 is precursor
dopamine effects?
inhibits release of prolactin as hormone, also has function of NT
hypothalamus is connected to the _____ ______ by what?
posterior pituitary / infundibular stalk
what makes up the infundibulum
pars tuberalis / infundibular stalk
what makes up the anterior pituitary
pars tuberalis / intermedia / distalis
what makes up the posterior pituitary
infundibular stalk / pars nervosa
pituitary is located where
hypophyseal fossa in sella turcica of sphenoid bone
what regulates growth, development, metabolism, homeostasis
hypothalamus and pituitary gland
hypothalamus to anterior pituitary glands movement of hormones occurs thru
pituitary portal system (capillaries)
releasing hormones
GHRH / TRH / CRH / GnRH / PRH
inhibiting hormones
GHIH (somatostatin) / PIH (dopamine)
posterior pituitary gland hormones
antidiuretic hormone (ADH / vasopressin)
oxytocin
pituitary gland is located
within the sella turcica of the sphenoid bone
anterior pituitary gland AKA:
adenohypophysis or pas distalis
posterior pituitary gland AKA:
neurohypophysis or pars nervosa
anterior pituitary consists of
pars distalis and pars tuberalis (partially covers infundibulum (like a sheath))
type of hormones produced by anterior pituitary gland
TROPIC hormones
the only tropic hormone that doesn’t exert effect on another endocrine gland
hGH
anterior pituitary hormones are synthesized and released into what type of circulation
venous
how is hGH secreted
when does its secretion increase?
in pulsatile manner
deep sleep
main function of hGH
promote synth and secretion of Insulin-like growth factors
hGH effects cells from where
liver, skeletal muscle, cartilage, bones synthesize
if deficiency in production of IGFs occur-what happens?
abnormalities - even if hGH is normal
what do IGFs do
inc protein synthesis
dec protein catabolism
enhances lipolysis (for ATP production)
stims growth
how does IGF influence carbohydrate metabolism
decreases glucose uptake to cells leaving it in the bloodstream for neuronal use; also stims liver to break down glycogen into glucose in hypoglycemic states
when is insulin secreted
when are IGFs secreted
in high blood glucose situations
in low blood glucose situations
how is hGH secretion affected by hypoglycemia
stimulates GHRH and inhibits GHIH by hypothalamus
hGH is secreted to increase IGFs which decreases glucose uptake and stims liver glycogenolysis
how does hyperglycemia affect hGH
stimulates hypothalamus to secrete GHIH
reduced levels of hGH and IGF
IGFs not needed because glucose is already present
factors that stimulate hGH
low blood sugar situations; deep sleep; dec serum fatty acids; inc serum amino acids
what hormones stimulate hGH secretion
testosterone / estrogen / Ghrelin (hormone right before meals)
factors that inhibit hGH
hyperglycemia / hGH itself (negative feedback)
GHIH (somatostatin)
when plasma T3/T4 levels are low
what is ACTH stimulated by
corticotropin-releasing hormone (CRH) from hypothalamis
stress-related stimuli (low blood glucose / trauma)
what controls production of cortisol
ACTH
ACTH controls production for what
cortisol, other GLUCOCORTICOIDS and androgens produced by the cortex of the adrenal glands
what controls prolactin secretion
prolactin releasing and prolactin inhibiting hormone (dopamine)
milk production and milk ejection is controlled by
prolactin and oxytocin
prolactin is weak by itself but works with
estrogen, progesterone, glucocorticoids, hGH, T4 and insulin
low levels of estrogen and progesterone just prior to menstruation are caused by
what do those low levels inhibit
prolactin
PIH (dopamine)
what stimulates the secretion of FSH
GnRH to anterior pituitary
what does FSH do in women and men
women: follicle production
men: sperm production
what type of feedback is exhibited by FSH levels
negative feedback
what stimulates the secretion of LH
GnRH to anterior pituitary
what does LH trigger and form
ovulation and corpus luteum
what is significant about the formation of corpus luteum
secretes progesterone
what triggers the secretion of estrogen and where does it secrete from
FSH and LH; ovarian follicular cells
what stimulates testosterone prod in males
LH
what is the collective name for group of peptide hormones produced in the skin, the anterior pituitary and other parts of the brain
melanocyte stimulating hormone
where does dopamine (PIH) inhibit the release of MSH?
ANTERIOR PITUITARY ONLY
melanocyte stimulating hormone can be found
skin, anterior pituitary and parts of brain
melanocytes may suppress
appetite
what inhibits TRH
increased levels of t3/t4 in blood stream
subsequently reduces TSH to reduce T3/T4 being made
what composes the posterior pituitary
pars nervosa
infundibular stalk
what hormones are stored in posterior pituitary
ADH (vasopressin) and oxytocin
what “stores” and “releases” but does not “synthesize”
posterior pituitary
what inhibits ADH
alcohol - end up dehydrating yourself by “breaking the seal”
how does ADH increase blood pressure?
vasoconstriction of arterioles
what is osmotic pressure measured by
osmoreceptors in the hypothalamus
what effects the amount of ADH secreted?
blood osmotic pressure and blood volume
what causes high osmotic pressure
dehydrate, hemorrhage, diarrhea, excessive sweating
loss of volume/fluid
what is the pressure that solutes are causing inside the plasma?
osmotic pressure measured by osmoreceptors
what do the osmosreceptors activate
production and release of ADH from neurosecretory cells in hypothalamus
describe the signal pathway for releasing ADH
osmoreceptor sends signal to neurosecretory cells in hypothalamus –> hypothalamus sends signal to posterior pituitary by the neurosecretory to secrete the STORED ADH
what are the ADH target tissues
kidneys (retain water) / sudoriferous (dec sweating) / vascular smooth muscle (arteriolar constriction)
what alters ADH
pain / stress / trauma / anxiety / drugs
what type of action is the release of oxytocin
positive feedback (oxytocin enhances oxytocin prod)
what does oxytocin effect in women
uterine contraction / milk ejection
what is needed for thyroid synthesis and secretion
presence of thyroid stimulating hormone
what type of feedback causes the hypothalamus to stop/slow TRH production
negative feedback
anything that increases cellular energy demand causes an increase in what?
t3 / t4 production
what are the functional units of the thyroid
follicles
what do follicular cells produce and what does it do
calcitonin - regulates blood calcium levels
T3 / T4 do what to metabolic rates
increases
describe T3 / T4
t3 active form much less abundant but more potent
t4 inactive form much more abundant but less potent
what produces thyroglobulin (TGB)
follicular cell
where is TGB produced and packaged
ER / golgi apparatus / released by exocytosis in colloid
Iodide requires what before it is useable
perioxidase oxidzses the iodide to iodine
What forms with iodine and TGB
DIT and MIT
what are T3 and T4 formed by
t3 = DIT and MIT ; t4 = MIT and MIT
once T3/T4 are formed in colloid what occurs
colloid pulled back into follicular cell by pinocytosis
colloid engulfed by lysosome and digests TGB and cleaves off T3/T4
T3/T4 bind to thyroxine BINDING globulin (for water solubility) and are sent to target cells thru blood stream
What are actions of T3 / T4
increase basal metabolic rate
stimulates synth of add. Na+ and K+ pumps
helps regulate metabolism
can enhance actions of catecholamines-upregulate beta adrenergic receptors (hyperthyroid patients experience inc heart rates and blood pressure)
what hormones do T3/T4 work with to accelerate body growth
hGH and insulin
what is the effect of calcitonin
high levels of serum calcium and HPO42 stimulate secretion
low levels inhibit
describe resorption
process of using/losing substance (breakdown of bone by osteoclasts)
describe absorption/reabsorption
process of gaining something
how does calcitonin affect osteoblasts and osteoclasts
inhibits osteoclasts because theirs already enough calcium in the blood; increases osteoblasts to use calcium to build
how does calcitonin affect the intestine and urine output
decreases calcium absorption in intestine since calcium levels are already high; increases calcium loss in the urine
in particular, how are the kidneys affected by calcitonin
increases calcium loss in urine; prevents cells in the distal convoluted tubule from reabsorbing more calcium
principal cells of parathyroid gland and what do they secrete
chief cells secrete PTH
how does calcium effect PTH
high levels of calcium inhibit secretion
low levels of calcium stimulate secretion
PTH effects osteoclasts and osteoblasts by
increase osteoclasts and inhibits osteoblasts
what does PTH do in the intestines and kidneys
increases calcium absorption in intestine
stimulates cells in distal convoluted tubule to reabsorb more calcium
two distinct sections of the adrenal glands
adrenal cortex and adrenal medulla
adrenal glands are covered by what and are supplied with blood how
connective tissue capsule
highly vascularized
3 zones of adrenal gland
zona glomerulosa / fasciculata / reticularis
what are the 3 zones and their hormones produced
zona glomerulosa: mineralcorticoids
fasciculata: glucocorticoids
reticularis: androgens
describe zona glomerulosa
mineralcorticoids;
effects mineral homeostasis;
ALDOSTERONE: sec. in elevated K+/H+ levels and low BP
Release of aldosterone is FLUCTUATING
promotes reabsorption of Na+ and water; K+/H+ excreted in urine
how does renin work
kidneys recognize low BP –> release RENIN –> causes conversion of angiotensinogen (made by liver) in angiotensin-I
angiotensin-I circulates into lung vasculature where it encounters angiotensin coverting enzyme (ACE)
ACE splits antiotensin-I into angiotensin-II -which circulates and increases BP
What does angiotensin II do
stimulates aldosterone production
causes inc in sympathetic activty
causes arteriolar vasoconstriction (same as ADH)
causes release of ADH (inhibits urine loss to inc BP)
where are androgens released
zona reticularis
androgens and what do they do
DHEA: weak; precursor for test, est, and androsten- and DHT
Androstenedione: weak, converted to testerone or esterone (precursor to estradiol)
DHT: more potent androgen than testosterone
made from conversion of testosterone
active in tissue where test is not
cells of the adrenal medulla synthesize?
chromaffin cells; catecholamines: norepi / epi
chromaffin cells are considered
modified sympathetic ganglion of the ANS
SNS sends signal thru what type of nerves to chromaffin cells
splanchnic
what effects do catecholamines
intensify sympathetic responses throughout the body
glands of pancreas
endocrine and exocrine glands
pancreas structure includes
head, body, tail
what are the endocrine cells and where are they located
excocrine acini; pancreatic islets (islets of langerhanns)
a - glucagon
b - insulin
d - somatostatin: GHIH
f - PP cells; secrete pancreatic polypeptide
how is glucagon released
pancreas senses low blood glucose - releases glucagon
what is the role of glucagon
liver breaks down glycogen
stims liver take up of AA to convert to glucose
stims breakdown of triglycerides to glycerol and FFA (lipolysis)
glucagon is regulated through what type of feedback
negative; glycogen levels dec as serum glucose increases
how is insulin released
small intestine releases GLUCOSE DEPENDENT INSULINOTROPIC PEPTIDE (GDIP - gastric inhibitory peptide) —> triggers release of insulin from pancreas
as nutrients are broken down and absorbed, it raises blood glucose for more insulin to be released
what does insulin do
facilitates glucose uptake into cells; stims glycolysis for ATP stims glycogenesis (glycogen prod) promotes trig and protein synth regulated thru negative feedback FROM serum glucose levels insulin levels dec as gluc dec
GHIHs actions are based in what
concentration based
GHIH acts in paracrine manner by inhibiting
insulin and glucagon
GHIH acts in endocrine manner by inhibiting
hGH from anterior pituitary gland
pancreatic polypeptides based on
concentration
pancreatic polypeptides
inhibit somatostatin release
inhibit gallbladder contraction
inhibits secretion of bicarb and pancreatic enzymes
APPETITE suppression
blood sugar in a fasted state
glucagon released; alpha cells of pancreas; acts on hepatocytes (liver cells); gluconeogenesis-glucose released to blood stream by hepatocytes
blood sugar after a meal
insulin released by beta cells; facilitates diffusion of glucose in cells; increases uptake of amino acids and conversion of glucose to glycogen
ovaries synthesize and secrete
estrogen, progesterone, inhibin and relaxin
what regulates menstrual cycle and maintains pregnancy and mammary glands for lactation
estrogen, progesterone, LH, and FSH
what are the roles for inhibin and relaxin
inhibin inhibits FSH - follice development
relaxin relaxes the pubic symphysis and relaxes the cervix
testes produce
testosterone and inhibin; testosterone reg sperm and inhibin exists do inhibit sperm production if concentration is too high
pineal gland secretes
melatonin - “biological clock”
heart produces
atrial-natriuretic peptide (ANP-a type natriuretic peptide) synth’ed when ATRIA is stretched to far - REDUCES blood pressure
B-type natriuretic when ventricles are stretched too far
kidneys release
renin: stimulates aldosterone release (aldosterone-inc sympathetic activity, arteriole vasoconstriction, release of ADH) (released at low blood pressure to raise BP)
glucocorticoids are given to who after surgery?
transplant patients
glucocorticoids decrease what?
decrease in eosinophils; atrophy in lymphatic tissue
kidneys release what three hormones
renin / calcitriol / erythropoietin
adipose tissue releases
leptin: satiety signal
adiponectin: helps to reduce insulin resistance
skin releases
cholecalciferol (modified to form vitamin D)
thymus aids with and releases
maturation of t cells; thymosin, thymic humoral factor, thymic factor, thymopoietin
liver releases
IGF-1 / angiotensinogen (raises BP) / thombopoietin (increase platelet production) / hepcidin (blocks release of iron)
GI tract releases
gastrin / cholecystokinin / glucose-dependent insulinotropic peptide AKA gastric inhibitory peptide / secretin
where is gastrin
secreted by G cells in stomach - stimulated by: protein ingestion, distention in stomach, vagal stim (promotes ACID BUILDUP)
what does gastrin stimulate
growth of gastric mucosa
cholecystokinin (CCK) secreted by
i cells of small intestine; meals containing fats and proteins; gallbladder contraction-slows gastric emptying-makes it more basic inside intestine
GDIP (gastric inhibitory peptide) secreted by
k cells of small intestine; stimulated by precense of glucose, fats, and amino acids
insulin release, inhibits H+ion secretion
secretin secreted by
s cells in the small intestine; fatty acids (contents less that 4.5 arrive increase of H+); inhibits effects of gastrin (makes it more basic)
eicosanoids secreted by
found in all cells of the body - except RBCs; include prostaglandins (PGs) and leukotrienes (LTs)-stimulates CHEMOTAXIS of WBCs and mediates inflammation
histamine secreted by
synthesized in any tissue with mast cells and platelets; physical trauma and immune response; contraction of smooth muscles-slows breathing; dilation-lowers BP; stims gastric acid secretion in stomach; inc permeability in caps and post caps
serotonin synthesized by
intestines, brain, CNS; serotonin made in intestines as reaction to bacterial colonies present; mood, anxiety, sleep etc. (can act as vasocontrictor or dilator due to concentration)
stress response has two types of stress
eustress, distress
stress response referred to as the
general adaptation syndrome (GAS)
what are the three stages of stress
alarm stage, resistance reaction, exhaustion response
describe the alarm stage (minutes to hours)
initiated by ANY stressor; cortisol by glucocorticoids; lymphocytes decrease; sympathetic response increases
describe the resistance reaction (hours to weeks)
recovery phase; cortisol declines, immune system reboots; sympathetic reduces, parasympathetic increases
exhaustion response
depletion of energy; prolonged exposure to cortisol, stim of sympathetic; fatigue-depression-anxiety
aging endocrines systems
hGH reduced, t3/t4 reduced, increased PTH likely due to decreased dietary calcium intake
aging endocrine systems adrenal coretex
becomes fibrous, dec of cortisol/aldosterone, medulla is unaffected (protected); high blood glucose because slower insulin release from pancreas