ENDOCRINE SYSTEM
OBJECTIVES
1) MECHANISMS OF HORMONE ACTION
2) CONTROL OF HORMONE SECRETION
MECHANISM OF HORMONE ACTION
Hormones act on specific / target cells
Hormones are present in very low concentrations
Hormones carry a specific message
HORMONES INFLUENCE CELLS BY
BINDING TO RECEPTORS
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MECHANISMS OF HORMONE ACTION
There are 2 main mechanisms of action:
Mechanism 1 (Water soluble hormone):
Amino acid derived hormones bind to a hormone
receptor on a cell membrane. They release
intracellular mediators which cause a change of
function within the cell.
WATER SOLUBLE HORMONE ACTION
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MECHANISMS OF HORMONE ACTION
Mechanism 2:
Involves hormones that are fat soluble
which are the steroid derived hormones.
Because they are fat soluble they can
penetrate the cell membrane.
A HORMONE’S MECHANISM OF ACTION
DEPENDS ON THE SIGNALING PATHWAY IT
ACTIVATES
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CONTROL OF HORMONE SECRETION
COPYRIGHT © 2016 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED.
ADRENOCORTICOTROPIC HORMONE
CONTROL OF HORMONE SECRETION
COPYRIGHT © 2016 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED.
END OF THE LESSON
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