Chapter 12: endocrine disorders Flashcards
purpose of hormones
regulate activity of certain cells/organs essential for ADLs
(digestion, metabolism, growth, reproduction, mood control)
major hormones
- thyroid
- parathyroid
- pancreatic insulin and glucagon
- epinephrine and norepinephrine
- several steroids
- gonadal hormones
what do hormone regulate
- digestive secretions and motor activity
- energy production/regulation
- internal homeostasis
- reproduction/lactation
- growth and development
- adaptation (acclimatization and immunity)
what are the 3 kinds of hormones
protein, amine, steroid
mechanisms of action for protein hormones
exerts effects on receptors in the membrane and bind to receptors on the outside of the membrane
which type of hormone has the most rapid effect
protein hormones
mechanism of action for amine hormones
also protein hormones so they show similar fast response
mechanism of action of steroid hormones
bind to the intercellular receptors and have slow action
negative feedback
hormone produces a physiologic effect that. When it is strong enough, further secretion of the hormone is inhibited, which then inhibits the physiologic effect
what could cause increased hormone secretion
stimuli from emotions, perceptions, or behaviors
primary hypothyroidism
decreased T3 and T4 levels
elevated TSH
secondary hypothyroidism
decreased T3, T4, and TSH
what type of things can cause secondary hypothyroidism
hashimotos disease, iatrogenic causes, drugs with iodine (lithium)
when are thyroid hormones NOT used for replacement
transient hypothyroidism during recovery phase of acute thyroiditis
levothyroxine sodium/thyroxine/L-thyroxine (T4)
(Synthroid, Levoxyl, Unithroid)
clinical uses
increase basal metabolism
enhace gluconeogensis
stimulates protein synthesis
liothyronine
(Cytomel, Triostat)
mechanism of action
enhances oxygen consumption by most tissues and increases basal metabolic rate
how is myxedema treated
with liothyronine and synthroid
metabolism of all thyroid preparations
liver
all thyroid preparations are excreted
through feces via bile
undergo enterohepatic recirculation
long term thyroid hormone usage can result in
decreased bone density of the hip and spine
protocol for reaching therapeutic dose of thyroid hormones
monitor TSH q2-3 months and adjust dose 10-25mcg at 6-8 week intervals until normal TSH levels are reached
What decreases T4 absorption
bile acid sequestrants, iron salts, antacids
what may decrease response to T4
estrogen
What medications are made less effective by T4
beta blockers, digoxin, warfarin