quiz 1 structure and mechanism of hormones Flashcards
endocrine is the opposite of the
nervous system
the endocrine and nervous system both
transmit signals around the body
the nervous system is built for
speed
the endocrine system is _____ and always uses
slower, hormones
there are about ____ distinct hormones in the human body
50
what are the three classes of hormones
amino acid derivatives
proteins
steroids
depending on the type, the _____ of a hormone can be different
mechanism
whats a mechanism again
how a chemical causes its desired effect
steroids are all synthesized fro the molecule ____
cholesterol
steroids all look like
cholesterol
what do steroids usually end in
ol or one
what are hormones that are proteins
long chains of amino acids
hormones that are proteins are significantly
larger than other hormones and water-soluble
amino acid derivatives are synthesized from
various amino acids
what do amino acids look like
they are small and look like animo acids
what do would amino acids (amino acid derivatives) look like
short chains of carbon
examples of amino acid derivatives
tyrosine, epinephrine
example of a protein thats a horome
insulin
where are hormones created
in glands located around the body
where are hormones secreted
into the bloodstream, where they travel to their intended target
steroids are not what? why?
water-soluble, because they are made from cholesterol which is a lipid
what do steroids require to travel through blood
a transport proteins
if amino acid derivatives are non polar they
need transport proteins
steroid hormones and most non polar amino acid derivatives are capable of what
passing through a cell’s membrane
once inside, steroid hormones and nonpolar amino acid derivatives do WHAT????
bind to receptors and form a hormone-receptor complex
what does the hormone-receptor complex do
enters the nucleus and causes upregulation or downregulation of proteins
nonsteroid hormones and polar amino acid derivatives CANNOT…
pass through a cell’s plasma membrane
to______ nonsteroid hormones must
bind to a receptor on the cell’s membrane
a membrane receptor activated by a nonsteroid hormone….
causes other molecules in the cell to invoke some kind of change
what are the most important hormones that the thyroid produces
T4 and T3
T4
thyroxine
T3
triiodothyronine
T3 and T4 are jointly involved in
regulating cellular energy processes around the body
differences between T3 and T4
T4 has one more iodine
the thyroid is what percentage T4
80%
the thyroid is what percentage T3
20%
inside cells T4 is
converted to T3 (only one active in cells)
when are T3 and T4 made
when the pituitary gland secrets TSH
why do we even have T4
more stable in bloodstream
TSH
thyroid stimulating hormone
T4 and T3 are
derivatives of the amino acids tyrosine, but have been combined with iodine
once secreted, what do T4 and T3 do
bind to the transport protein TBG and travel through blood
TBG
tyroxine-binding globulin
know the tyroid gland
ok
goiter
an enlarged thyroid gland (developing countries)
what happens right after T3 and T4 enter the cell,
T4 is converted to T3, T3 passes through the nuclear membrane and bind to TR
TR
thyroid hormone receptor
what happens without T3
the thyroid receptor binds to DNA and blocks certain genes from being expressed
what does T3 do
binds and causes TR to move off the DNA, allowing those genes to be expressed
the newly expressed genes because of T3 binding to TR and moving it off dna do …
increase the rate of cellular metabolism in cells all across the body
hyperthyroidism
when the thyroid makes too many hormones
hypothyroidism
is when the thyroid does not make enough
PTH is made by
chief cells in the parathyroid glands
PTH is made in response to
low blood calcium levels (hypocalcemia)
PTH is a…
protein
PTH is made of how many amino acids
84 (kinda small)
PTH binds to
binds to parathyroid hormone receptors on the outer membranes of osteoblasts and osteoclasts
PTH causes
osteoblasts to slow down
osteoclasts to speed up
… releasing more calcium from bone and into the blood
PTH also binds to receptors…..
on the kidney s
PTH causes what on the kidneys
upregulation of an enzyme from a gene on DNA which converts calcidiol into Vitamin D
when is vitamin D synthesized
when PTH send a signal to the kidneys
vitamin is also a what
hormone
what do people say that is only partly true
that sunlight gives you vitamin D
vitamin D is what kind of hormone
a steroid hormone since it is synthesized from cholesterol
what does sunlight directly cause
cholesterol to be converted into cholecalciferol in the skin ……
cholecalciferol….
converted into calcidiol in the liver
calcidiol…….
is converted to vitamin D in the kidney
vitamin D……
attaches to vitamin D binding protein in the blood because it is not water soluble
once vitamin D is in the blood
it travels until it finds and binds to a Vitamin D receptor
where are vitamin D receptor located
in the nucleus of small intestine cells
vitamin D and vitamin D receptor form
a hormone-receptor complex
what does the hormone-receptor complex of vitamin D and vitamin d receptor do
binds to DNA and causes increased expression of protein calbindin
calbindin
a channel in the membrane of small intestine that allows calcium to enter and be digested
with more vitamin D
calcium levels increase
