Endocrine Flashcards
paracrine
chemical signalling to nearby cells
autocrine
chemical signaling of cells among the same type
major endocrine glands (10)
- pineal gland
- parathyroid
- thyroid
- hypothalamus
- pituitary
- thymus
- kidney
- adrenal
- pancreas
- ovary/testes
what type of feedback loop primarily regulates the endocrine system
how is regulation accomplished
negative
secretion of inhibiting or enhancing factors
short feed back loop
a feedback loop where a trophic hormone from the pituitary inhibits production of stimulating factors from the hypothalamus
long feedback look
a feedback loop where the end hormone produce by trophic stimulation will inhibit production at the hypothalamus and pituitary
which is more relevant, long or short feedback loops?
why?
long, because they work on the hypothalamus and the pitutiary
how are hormones sent through out the body
dissolved in blood or bound to carriers
what type of hormones will dissolve in blood
what type of hormones will need a carrier
water soluable
lipid soluble
target cell
the end-target of a hormone that produces a response within the cell
two ways that hormone-receptor complexes elicit effects in target cells
2nd messanger
DNA transcription leading to protein production
what links receptors of the same “family)
they have a similar structure
what can happen if a homone is present in high enough concentrations
the hormone can interact with receptors of the same family
four types of receptor hormone interactions
agonists (stimulate receptors)
antagonists (block receptors)
down regulation
change receptor affinity
why is it imporant to know the amount of a hormone that is bound vs free
a bound hormone can’t do anything
T/F horomes are secreted continuously
false they are usually in pulses
three amino acid hormones
dopamine
thyroxine
catecholamines
four small neurpeptide hormones
GnRH
TRH
vasopressin
somatostatin
5 protein/glycoprotein hormones
FSH
LH
TSH
HCG
Insulin
PTH
three types of steroid hormones
estrogens
androgens
progestins
two types of vitamin derived hormones
retinoids (vitamin A)
vitamin D
5 general categories of hormones
amino acid
neuropeptides
proteins/glycoproteins
Steroids
Vitamin deriviatives
why can FSH, LH, TSH, and HCG cross react with each other
they have receptors in the same family
three facts about peptide/protein/glycoprotein hormones
water soluble
interact with cell membrane
work through second messanger
three facts about steroid hormones
insoluble
requires transport molecules
causes DNA transcription and translation
explain why endocrine systems are homeostatic
they respond to outside challenges to maintain homeostasis
three environmental changes that can cause an endocrine response
nutritional
thermal
existential
what is the main task of the thyroid
to produce T3 ad T4
what is the full name of T3
T4
which is the main functional hormone of the thyroid
triodothyroinine
tetraiodothyroinine
T3
which thyroid hormone is most readily available
why is this effect in treatment
T4
because T4 is converted to T3 in tissues
where are T3 receptors found
in alll most all human tissue
5 locations in the body with especially high numbers of T3 receptors
brain
heart
muscle
kidneys
gonads
what will the response to T3 be
increased…
energy utilization
protein synthesis
sensitivity to other hormones
two regulators of thyroid function
thyrotropin-releasing hormone (TRH)
thyrotropin (TSH)
what is the function of TRH
stimulates the production of TSH and prolattin
what is the effect of thyrotropin (TSH)
increased T3 and T4
what wil happen if the thyroid gland is dysfunctional
what can also happen?
TRH and TSH will be produced in high amounts
prolactin can also be produced
two main types of hyperthyroidism
graves disease
toxic nodular goiter
what are the laboratory tests that will confirm hyperthyroid
very low or absent TSH
very high T4
sometimes autoimmune tests are positive
what nervous system are many of the symptoms of hyperthyroidism related to
sympathetic nervous system
- restlessness
- insomnia
- tremor
- weight loss
- heat intolerance
three disease that can be triggered by hyperthyroid
acute chest pain (MI)
CHF
Arrhythmia
why would you check for hyperthyroidism in new onset a fib
because hyperthyroid can trigger arrhytmias
what is the most common type of hyperthyroidism (60-80%)
graves disease
what causes graves disease
auto-antibodies that bind and active TSH receptors
what is the gender ratio of patients with graves disease
female 8:1
exophthalmos
cause
protrusion of the eyes found in 20-40% of Graves patients
caused by lymphcytic infilitration of the eyes
what is the cause of goiters
is there a gender bias
what may be a contributing factor
unknown
no, 1:1
low iodine may contribute
in what hyperthyroid condition does exopthalmos not occur
goiter
what is the treatment plan of hyperthyroid
control symptoms
prevent thyrid storm
plan long term control
thyroid storm
acute high levels of T3 and T4 that can cause hypotension and fever
two long term control options for hyperthyroid
thyroid excision or destruction
continued antithyroid drugs
what do beta blockers do in treating hyperthyroid
four results of treatment
block sympathetic pathways
rapid reduction in anxiety, restlessness, tremor, palpitations
what are two methods of lowering T3 and T4 in hyperthyroidism
prevent hormone release
stop T3 and T4 production
what drug can stop the relase of T3 and T4
potassium iodine
what drugs stop the production of T3 and T4
when are they most effective
thioamides
when combined with beta blockers and potassium iodine
what is the preferred method of treatment to definatively cure hyperthyroid
what makes it good
ablation wth radioactive iodine
because it spares the parathyroid
why can radioactive iodine be used to ablate the thyroid
because the thyroid is the only place where iodine is stored in the bdoy
what lab tests confirm hypothyroid
Low T4
very high TSh
five hypothyroid symptoms
- cold intolerance
- hair loss
- weight gain
- weakness
- dry skin
primary hyperthyroid
the 99% of hypothyroidism that is caused by failure of the thyroid galdn
secondary hyperthyroid
failure of the pituitary to release TSH
four causes of hypothyroid
post thyroidectomy/ablation
hashimotos thyroiditis
Drug induced
dietary iodine deficiency
what is the most common cause of hypothyroid
hashimotos thyroiditis
what drug will cause hypothyroid
amiodirone
how common is hashimotos
is there a gender bias
1-4/1000
females 1:4
what happens in hashimotos
the thyroid is infiltrated with T and B cells
what is the first line treatment for hypothyroid
daily thyroxine
two parts of the adrenal gland
medulla
cortex
what is the function of the adrenal medulla
secretes epi/norepinephrine
what is the function of the adrenal cortex
secretes glucocorticoids, androgens, mineralocorticoids
describe the negative feedback loop that regulates adrenal function
pituitary secretes ACTH
adrenal cortex secretes cortisol
cortsol inhibits ACTH secretion
cushing syndrome
a cluster of symptoms caused by excess cortisol
three causes of Cushings
iatrogenic
secondary adrenal hyperplasia
primary adrenal hyperplasia
what is a common iatrogenic cause of cushings
prednisone
what causes cushings disease
what is the distinction between this and secondary adrenal hyperplasia
an ACTH secreting tumor on the pituitary
there isn;t one
where are other ACTH secreting cells located beside the pituitary
small cell lung cancers
primary adrenal hyperplasia causes
idiopathic
neoplasm
congenital
five effects of cortisol
increases glucose production
raises blood pressure
raises blood sugar
lowers lymphcyte and monocyte levesl
what two effects of cortisol are considerd to improve resistance to stress
increased glucose availibility
increased blood pressure
5 adverse effects of cortisol
weight gain
striae
moon facies
HTN
peptic ulcers
T/F most chronic conditions are no effected by cortisol
false, many (such as DM and HTN) can be exacerbated by cortisol
how does cortisol exacebate HTN?
DM
HTN: increase salt intake
DM: increase blood sugar
tests and exams to confirm cushings
elevated cortisol
cortisol suppression test
Low ACTH levels
imaging
what pattern is lost with cushing syndrome
the diurnal pattern which causes higher cortisol in the morning and lower at night
three possible treatment plans for cushings
stop glucocorticoids
surgery
antiglucocorticoid medication
what diagnoses for cushings have a good prognosis?
poor?
good: cushings disease and iatrogenic cushings
bad: adrenal carcinoma and small cell lung cancer
define diabete mellitus
a disorder characterized by chronic hyperglycemia due to relative or absolute deficiency of insulin, or resistance to insulin
what cells in the pancreatic islets that secrete insulin
glucagon
beta cells
alpha cells
which are more prominent, alpha or beta cells?
alpha (75% to 20%)
what is insulin
what compound is it derived from
how does this happen
a small protein
conversion of proinsulin into insulin
removal of connecting C peptide
what is the fucntion of C peptide after it is removed from proinsulin
what would high levels of c peptide indicate?
low?
nothing
high levels = type 2 DM
low = type 1 DM
two actions of insulin
inhibit catabolism
promotes anabolism
how does insulin promote anabolism
increase glycogen production and storage
promotes triglyceride synthesis in fat cells
incrases protein synthesis in muscle
how does insulin inhibit catabolism
inhibits glycogen break down
inhibits amino acid and fatty acid break down
describe tie etiology of Type I DM
an autoimmune disorder that causes rapid loss of beta cells
what triggers beta cell loss in type I DM
can be a virus or toxin such as mumps or coxsackie, as well as a genetic predispostion
describe the etiology of type II DM
a very slow loss of beta cells causd by genetic or obestity
three Ps of diabetes
polyuria
polydipsia
polyphagia
two other symptoms of diabetes that aren’t the 3 Ps
weight loss despite increased appetite
fatigue
fatal complication of diabetes
diabetic ketoacidosis
what typpe of diabetics are most likely to have DKA
type one
five chronic complications of DM
CAD
PVD
nephropathy
neuropathy
retinopathy
what causes DKA
hyperglycemia >300mg/dl causes keto acids to accumulate
five symptoms of DKA
tachycardia
dehydration
SOB
lethargy
coma
four conditions that are most commonly caused by DM
chronic renal failure
neuropathic pain
blindness
gangrene caused limb amputation
what was the mean survival of a diabetic patient before 1922
after
what changed?
5 year <5%
increaed to 30-40 years
insulin was discovered
when will most diabetic have complications
after 20 years
what is the treatment for type I DM
type II
type I = insulin
type II = insulin plus other stuff
five non-insulin treatments of DM
reduce insulin resistance
stimulate secretion fo endogeneous insulin
reduce glucagoon
reduce glucose absorption
enhance urinary secretion
T/F complete control of glucose is bad
true, it decreases longevity
what does tight management of DM entail
diet
frequent blood assays
medication 3-4 times daily
flexible dosing
what is the hallmark of type II DM
insulin resistance
two stratgies to reduce insulin resistance
weight loss
medication (biguanides and thiaxolidinediones)
what is the most common medication for type II DM
metformin (glucophage)
medication used to decrease glucagon secretion
glucagon like peptide 1
where does glucagon like peptide naturally come from
what does it do
L cells in the intestine
opposes insulin
