FINAL EXAM STUDY GUIDE
ENDOCRINE
Endocrine, nervous and immune systems work together to regulate responses to internal
and external
... [Show More] environment
Hormone release is regulated by:
o Chemical factors (BGL, Ca levels)
o Endocrine factors (cortisol)
o Neural control- ANS stimulates
Negative feedback- MOST COMMON, occurs when a changing chemical, neural or
endocrine response DECREASES synthesis and secretion of hormone
Positive feedback occurs when a neural, chemical, or endocrine response INCREASES
synthesis and secretion of hormone.
o Also occurs when increased hormone level further increases synthesis and
secretion of that same hormone
o Ex- cyclic rise of estradiol levels
Hormone receptors of target cells have 2 functions
o Recognize and bind with high affinity to their particular hormones
o Initiate signal to appropriate intracellular effectors
o The sensitivity or affinity of the target cell to a particular hormone is r/t the
concentration of receptors for cell- more receptors= more sensitive to stimulating
effects of hormone
High concentrations of hormone decrease the number or affinity of receptors per cell=
DOWNREGULATION
o The cell can adjust its sensitivity to the concentration of signaling hormone
o Receptors on plasma membrane are continuously synthesized and degraded so
changes in receptor concentration may occur within hours
Thyrotoxicosis
Condition that results from any cause of an increased amt of TH levels
HYPERthyroidsm= form of thyrotoxicosis which excess amts of TH are secreted
Thyrotoxicosis and hyperthyroidism used interchangeably
More prevalent in women and iodine-deficient geographical areas
Diseases that cause primary hyperthyroidism= Graves’ disease, toxic multinodular goiter,
toxic adenoma
Secondary- less common and caused by TSH-secreting pituitary adenomas
S/S are attributable to metabolic effects of increased circulating levels of TH
o Increased metabolic rate with heat INTOLERANCE
o Thin hair, exophthalmos, normal or enlarged thyroid (goiter), tachycardia (HF),
wt loss, diarrhea, N/V, warm skin, sweaty palms, hyperreflexia, pretibial
myxedema, restlessness, insomnia, fatigue, tremor
Treatment= antithyroid drug therapy, radioactive iodine, surgery. Major complication of
hyperthyroidism tx= hypothyroidism
Thyrotoxic crisis (Thyroid Storm) [Show Less]