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131 Cards in this Set

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  • Back
mediator molecules of
-nervous system
neurotransmitters
neurotransmitters are released where? and in response to what?
locally
nerve impulses
mediator molecules of endocrine system
hormones
hormones are carried by....
to....
carried by blood
to tissues throughout the body
types of neurotransmitter target cells
muscle (all types)
gland cells
other neurons
types of hormone target cells
all body cells
time to onset of neurotransmitter action
milliseconds
time to onset of endocrine action
seconds, to hours or days
duration of nervous response vs. endocrine response
brief vs. longer
functions of the endocrine system
regulation of: extracellular fluid levels, metabolism, biological clock, contraction of cardiac/smooth muscle, glandular secretion, some immune function
growth, dvpt (fetal to adult)
reproduction
exocrine glands
secrete (...)
into (....)

examples: (4)
secrete products
into ducts
which empty into body cavities or body surface

include: sweat, oil, mucous and digestive glands
endocrine glands
secrete (...)
into (...)

examples:
secrete products (hormones) into bloodstream

pituitary
thyroid
parathyroid
adrenal
pineal
organs that secrete hormones as a 2nd fxn
hypothalamus
thymus
pancreas
ovaries
testes
kidney
stomach
liver
small intestine
skin
heart
placenta
endocrine tissue can be found distributed in 3 different ways:
distinct, discrete organs

clusters of cells in mixed organs

widely dispersed (diffuse) cells in non-endocrine organs
types of endocrine hormones (characterized by where they go)
a) circulating hormones

b) local hormones
paracrines
and
autocrines
how many receptors can be found on one target cell?
2000-100,000
down-regulation
excess hormone, produces decrease in # of receptors

receptors undergo endocytosis and degradation

decreases sensitivity of target cell to hormone
up-regulation
deficiency of hormone, produces an increase in the number of receptors

makes target tissue more sensitive to the hormone
RU486
Synthetic Hormone that blocks progesterone receptor:
(mifepristone) binds to the receptors for progesterone (necessary for implantaton and maintenace of ovum in the uterine wall) prevents progesterone binding and prevents maintenance of uterine wall for pregnancy- inducing abortion
general mechanisms of hormone action
hormone binds to cell surface or receptor inside target cell

cell may then
a) synthesize new molecules
b) change permeability of membrane
c) alter rates of reactions
in hepatocytes, insulin stimulates
glycogen synthesis
in adipocytes, insulin stimulates
triglyceride synthesis
lipid soluble hormones
move through the plasma membrane and often bond to a nuclear receptor
water-soluble hormones
must link to a transmembrane receptor as a 1st messenger

and work via a second messenger system (eg G protein)
control of hormone secretion is generally by what type of feedback?
negative
example of positive feedback control of hormone secretion
oxytocin on SM of uterus during labor
hypothalmus makes (....)
that travel via (....)
directly to the (....)
to induce the release of (...)
specific releasing hormones
that travel via a closed portal system
directly to the anterior pituitary
to induce the release of specific pituitary hormones
posterior pituitary is connected to what gland?
hypothalmus
the hypothalmus sends long axons to...
the posterior pituitary
the hypothalamus releases (....) or (....) into the capillary system of the (...) pituitary
ADH or oxytocin
released from hypothalmus into the capillary system of the posterior pituitary via long axons
pars nervosa is also called
posterior pituitary, where hormones produced in the hypothalmus are released
pars distalis
anterior pituitary. stimulated by TRH (released by hypothalmus) to release TSH into circulation (which stimultaes thyroid follicular cells)
TRH is released by ...
hypothalmus
hypothalamus stimulated to release TRH by
low blood levels of T3 and T4
T3 and T4 are secreted by (...) following stimulation by
thyroid gland secretes (...) and (...) in response to stimulation by TSH
hormones that are made in the epithelial cells of thyroid follicles
T3 and T4
thyroid hormones are stored
as thyroglobulin in colloid
what is required for the conversion of thyroglobulin into T3 and T4?
iodine (trapped and oxidized, allowing for iodination of tyrosine residues of TGB)

allows coupling of:
MIT (T1) + DIT (T2) = T3
DIT + DIT = T4
PTH is secreted in response to...
parathyroid secretes PTH in response to serum Ca++ levels
PTH activiates
osteoclasts to dissolve Ca++containing bone
and induces the GI tract to increase calcium absorption and the kidney to retain calcium
Calcitonin is secreted by
secreted by parafollicular cells of the thyroid gland
PTH is made by
cheif cells in the parathyroid
oxyphil cells are found in
parathyroid
fxn unknown
gland that serves as two functional endocrine organs
adrenal gland
medulla and cortex
regions of adrenal cortex
zona glomerulus
zona fasiculata
zona reticularis
factors acting on zona glomerulus
angiotensin and ACTH (corticotropin)
hormones secreted by zona glomerulus
mineralocorticoids (aldosterone)
factors acting on zona fasiculata
corticotropin (ACTH)
hormones secreted by zona fasiculata
glucocorticoids (cortisol)
factors acting on zona reticulares
corticotropin (ACTH)
hormones secreted by zona reticularis
androgens
hormone that acts on all zones of adrenal cortex
corticotropin (ACTH)
adrenal medulla responds to what kind of stimulation
parasympathetic
adrenal medulla releases
epinephrine or norepinephrine
norepinephrine is secreted by adrenal gland when...
blood vessels directly supply medulla (blood lacks glucocorticoids from fasciculata)
no methytransferase enzyme induced in these chromaffin cells, therefore...
epinephrine is secreted by adrenal gland when...
blood vessels in adrenal cortex pass through zona fasciculata cells in medulla

in response to ACTH glucocorticoids are released into blood, carried to medulla

glucocorticoids induce methytransferase production by chromaffin cells, thus,

... epinephrine is secreted
alpha cells secrete
glucagon
beta cells secrete
insulin
glucogon
makes glucose more avaiable in the blood by stimulating the breakdown of glycogen and fat through glycogenolysis and lipolysis
insulin
promotes storage of energy via glucose, particularly in liver, decreases blood glucose
Type I diabetes
autoantibodies against B cells
Type II diabetes
??
pineal gland is involved in (...)
responds to (...)
diurnal cycles
light intensity
steroids
-lipids derived from cholesterol
-produced on SER (by enzymes)
-lipid droplets are cholesterol ester precursors???
hormones derived from tyrosine
tyroxine
and epinephrine
thyroid hormones are bound in the blood to...
TBG (Thyroxine binding globulin)
lipid soluble proteins must attach to transport proteins in order to:
-improve transport by making them water soluble
-reduce hormone loss by glomerular filtration
-create reserve of hormone
free fraction
percent of hormone not bound to transport protein

only .1 to 10%
water-soluble hormones
amine, peptide and protein hormones

and
eicosanoids (fatty acid derivatives)
serotonin, melatonin, histamine, epinephrine are all soluble in
water
eicosanoids
derived from achachidonic acid (fatty acid)
prostaglandins, leukotrienes, thromboxanes
1st and second messengers are typically soluble in
water
amplification allows one molecule of epinephrine to result in
breakdown of millions of glycogen molcules into glucose molecules
cholera toxin causes
G protein to lock in activates state in intestinal epithelium
cAMP causes intestinal cells to actively transport chloride (Na+ and water follow) into the lumen
causes massive watery diarrea
ovulation is an example of what type of secretion pattern
pulsatile, regulated by LH which fluctuates with diurnal rhythms
binding of an agonist
induces events leading to a biological effect
antagonist
competes for receptor, blocking binding of an agonist
synergism
two or more hormones working together to enhance a biological effect
permissive effect
one hormone increases the activity of a second hormone
master endocrine glands
pituitary and hypothalamus
since their hormones control other endocrine glands
hypothalamus receives input from
cortex, thalamus, limbic system and internal organs
hypothalamus controls what gland?
controls pituitary by secreting 9 different releasing or inhibiting hormones
what division of the pituitary is more cellular
anterior, pars distalis
infundibulum stalk is found in which division of pituitary?
pars nervosa
posterior pituitary
neurohypophysis
hormones of the posterior pituitary are produced where?
hypothalamus
what hormones travel down hypothalamo-hypophyseal tract?
oxytocin and ADH
travel from hypothalamus to cap. bed of posterior pituitary
target tissue of oxytocin
uterus in late labor
pitocin
mimics oxytocin- induces labor
ADH target tissue
kidney, promotes water retention, causes vasoconstriction "pressor effect"p
pituicytes are found where?
posterior pituitary
herring bodies are found where?
posterior pituitary
herring body
???? dilation in neurohypophaseal tract
empty vesicles carried back to cell body on
dynein
hypothalamo-hypophyseal portal system
primary capillaries from portal system in anterior pituitary form secondary capillaries restrict activators within local circulation????
TSH target tissue
thyroid gland
action of TSH
secretion of T3 and T4
GH target tissue
most tissues
action of GH
promotes protein synthesis and growth
prolactin target tissue
mammary glands
action of prolactin
promotes growth of gland and milk secretion
ACTH target tissue
adrenal cortex
principal action of ACTH
promotes secretion of glucocorticoids and mineralocorticoids
FSH target tissue
gonads
FSH action
gamete production in both sexes, secretion of estrogen in females
LH target tissue
gonads
LH principle action
female sex hormone secretion and ovulation in females;
testosterone secretion in males
TRH structure
3 AAs
TRH stimulates
thyroid stimulating hormone
GHRH structure
44 AAs
GHRH stimulates
stimulates GH secretion
Prolactin-Inhibiting hormone structure
dopamine????
corticotropin RH stimulates secretion of
adrenocorticotropic hormone
gonadotropin RH
follicle-stimulating hromone (FSH) and luteinizing hormone (LH)
posterior pituitary makes up approx what % of gland
10% of pituitary gland
anterior pituitary makes up approx what % of gland
90% of pituitary gland
endocrine regulated by serum calcium levels
parathyroid
parathormone
secreted by parathyroid in response to serum calcium levels
raises serum calcium levels by:
increasing osteoclast activity
increases Ca2+ resorption by kidney
promotes formation of calcitrol by kidney
and inhibits resorrption of phoshate (HPO4)
calcitrol
produced (from vit D3) by kidney
increases Ca2+ and Mg2+ absorption by intestinal tract
calcitonin
reduces serum calcium levels (produced by C cells in thyroid)
C cells
parafollicular cells of thyroid
secrete calcitonin (which reduce serum Ca2+ levels)
iodine deficiency
causes a decrease in thyroid hormones (negative feedback mechanism- not "feeding back")
decrease in both thyroid and anterior pituitary activity
cell types in parathyroid
chief cells (parathromone)
oxypil cells (fxn unknown)
parathormone is made by what type of cells
chief cells in the parathyroid
zona glomerulosa
just inside capsule or adrenal gland
outermost zona of adrenal cortex
secretes mineralcorticoids (aldosterone) in response to ACTH and angiotensin

increases Na+ resorption by kidney
zona fasciculata
secretes glucocorticoids (e.g. cortisol) in response to stimulation by ACTH
important in:
metabolism
inflammatory response
supresses immune system
zona reticularis
between the zona fasiculata and medulla of adrenal gland

secretes androgens (e.g. testosterone, estrogen) and small amts of cortisol in response to ACTH
region of adrenal gland characterized by straight cords of cells
zona fasciculata (intermediate zona of cortex)

stimulated by ACTH
secretes glucocorticoids
zone glomerulosa
characterized by rounded clusters of cells
secrete mineralcorticoids (aldosterone)
epinephrine is secreted by...
-chromaffin cells of adrenal medulla
-that have been supplied by sinusoidal vessels ( travel zona fasiculata of adrenal cortex- where glucocorticoids are secreted)

glucocorticoids induce the production of methyltransferase (an enzyme that adds the extra methyl group to
norepinephrine is secreted by...
chromaffin cells of the renal medulla
supplied by medullary arterioles (go directly to medulla)
do not carry glucocorticoids, no methyltransferase induced, no extra methyl group
colchine
used in creating chromosome spread

added to culture to to block microtubules, stopping the chromosomes at the end of prophase, before their movement into metaphase.