module 3- endocrine Flashcards
hormone function
allow cells that are not beside each other to communicate in synchronized functions
paracrine vs neurotransmitter communication
P- short, local
N- long, distant
endocrine cells function
dump message into blood & only effector will be the cell that has a receptor for that message
neurohormone
nerve cell that drops a neurhormone into blood & communicates with faw away cells
parahormone function
messages to another animal
3 types of hormones
1) peptides & proteins
2) amines
3) steroids
amines are derived from
tyrosine
steroids
neutral lipids derived from cholesterol
peptides
chains of amino acids- long or short
what are all steroids derived from?
cholesterol
T or F: steroid structures are similar but have very different affects on the body
T
4 types of steroids & what they are
1) testosterone- male
2) estradiol- fermale
3) corticosterone- stress
4) aldosterone- water retention
why does insulin get injected, not taken in pill form
b/c peptides get denatured in the stomach
why can estrogen for birth control be taken using pills?
estrogen does not get denatured in the stomach
peptides & catecholamines are ( ) and steroids & thyroid hormones are ( )
hydrophilic, lipophilic
where are peptides produced
ribosomes on rough endoplasmic ret
preprohormone
long chain of amino acids
how are peptides synthesized steps
1) preprohormone is synthesized
2) pruned to prohormone
3) cut to active hormone in golgi complex
4) gets concentrated in golgi complex & packaged into vesicles to be ready for use
5) released into body via exocytosis when stimulated
where do the bits from cutting of the peptide hormone go?
used to make other things from POMC
steroid hormone synthesis steps
1) cholesterol from diet or LDL
2) enzymes modify cholesterol into hormone
3) steroid hormone is produced & secreted right away b/c they cannot be stored
4) diffuse through membrane into blood & some undergo further modifications
amine hormone synthesis
1) derived from tyrosine
2) undergoes modification
3) stored until needed
4) thyroid hormone undergoes further processing after release
peptides, steroids & thyroid hormone transport
peptides: freely in plasma or bound to carrier
steroids & thyroid hormones: dragged by plasma protein b/c they cannot dissolve
T or F: only free lipophilic hormones are active
T
what is the goal of hormone transport?
maintain hormonal equilibrium through feedback loops
what occurs after a free hormone has interacted with its target cell
it gets inactivated
tropic vs non-tropic hormones & their targets
tropic- regulate production/secretion of another hormone by acting on it
target: endocrine tissues
non-tropic: final product, acts on regular cells & does not regulate other hormones
target: non-endocrine tissue
T or F: hormones act like key & lock system
T
2 categories of receptor & hormone interactions
1) membrane receptors
2) internal receptors
membrane receptors
bind a receptor outside plasma membrane to start a chain of reactions
internal receptors
bind to specific receptors inside the cell, often produce new protein
where does hormone binding occur?
HRE (hormone response element)
hormone effects on transcription steps
1) hormone gets dropped & tries to leave cell
2) finds specific receptor & binds = activates it
3) goes to nucleus & finds HRE to activate some gene
4) cell makes a new protein
negative feedback loops
counteracts any change
TRH, TSH, TH- tropic or non-tropic
TRH & TSH= tropic
TH= non-tropic
when are neuroendocrine reflexes used for hormonal regulation?
to produce a sudden increase in hormone secretion in response to an external stimulus
catecholamine vs cortisol release time
cat- released within seconds, very fast so cannot measure
cort- peaks after 1 hour
what is circadian control and when is it used to regulate hormone secretion?
anticipatory regulation allows your body to adjust cyclical changes
example- cortisol cycle
when is cortisol the highest?
early morning
hasimotos disease
destroys thyroid hormone =no thyroid hormones
hormone elimination is primary through
urinary excretion
human chorionic gonadotropin hormone (hCG)
detecting hormone produced by the fetus
the response of a cell to hormone is correlated with
number of receptors
downregulation of hormones & example
presence of hormones reduces number of receptors on the cell
example-type II dabetes
type II diabetes
too much insulin so your cells stop responding
pineal gland
controls circadian rhythm via light/dark and secretes melatonin
in low light ( ) melatonin is produced
more
melatonin effects
sleep, blood pressure, & anti-imflammatory
ADH & oxytocin are released by the ( ) but produced in the ( )
posterior pit, hypothalamus
what type of diabetes is caused by ADH deficiency
diabetes insipidus
central vs nephrogenic diabetes insipidus
c: no ADH secretion
n: kidneys do not respond to ADH
prolactin vs oxytocin in relation to milk
p- milk production
o- milk delivery
what 2 hormones stop milk from being produced when not needed
progesterone & estrogemn
what hormone increases during pregancy
prolactin
how many hormones does the anterior pit produce?
6
portal system
2 capillary beds back to back without going through the heart
how hormones travel
portal system pathway
heart, artery, capillaries in hypothalamus (picks up hormone), veins, capillaries in anterior pit (drops hormone & picks up new one, veins, heart
if hypothalamus drops TRH, the anterior pit stimulates ( ) TSH
release of
hypothalamus secretes its own tropic hormone in response to
stress
what occurs if you do not have stress
corticosteroids have antigrowth effects
when does GH get released
when body is running out of glucose
overall effect of GH on metabolism
mobilize fat stores & keep glucose for the brain
indirect effect of GH on growth
effects are mediated by IFGs
how are IGF-1 stimulated
by GH
what is the most important IGF for growth
IGF 1
IGF-2 is important for
muscle growth
T or F: IGF-2 is independent of GH
T
hyperplasia
increase number of cells
hypertrophy
increase in the size of the cells
IGF-1 is important for
soft tissue and bone growth
T or F: bone is a living tissue
T
what are the 2 components of bone
cells & extracellular matrix
why is a bone strong
it is calcified
what is a long bone made of?
diaphysis, epiphysis & epiphyseal plate
long bone formation steps
1) cylindrical shaft- diaphysis
2) articulating knobs at both end- epiphysis
3) layer of cartilage separating the 2- epiphyseal plate
how do bones grow thicker vs longer
thicker- adding new bone on top of old bone
longer: proliferation of cartilage cells in epiphyseal plates
T or F: thickness of cartilage reflects how much growth you have left
T
what is the epiphyseal plate made of
chondrocytes (non-calcified)
how does a bone grow?
1) chondrocytes divide & start creating a new layer
2) everything gets pushed down to grow the knob
3) calcification of extracellular matrix
4) dead chrondocytes are cleared by osteoblasts
5) osteoblasts deposit bone over top of everything, die & become regulate bones
6) plate shifts up & bone gets longer
osteoblast vs osteoclasts
osteoblasts- builds
osteoclasts- blasts
GNRH vs GHIH stimulatory or inhibitory? where do they come from?
GNRH- stimulatory
GHIH- inhibitory
comes from hypothalamus
high amino acid concentration & low fatty acid concentration does what to GH
increase
growth hormone deficiency
- cause
- effect on newborn vs adult
- treatment
caused by pituitary issues or congential
newborn: dwarfism
adult: no effects on growth, but see effects on soft tissues
treatment: injection of GH
provacative test
tests for GH deficiency
injects insulin & if peaks then normal, but if no peak then GH problems
growth hormone hyperproduction
- cause
- effect on children vs adults
- treatment
- how to diagnose
cause: pit issues or congenital
children: gigantism
adults: acromegaly - soft tissue overgrowth
treatment: injection of GHIH
diagnose: if given glucose, GH will not drop
