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Final

study notes for lecture five: adrenal gland


Department
Physiology
Course Code
PSL201Y1
Professor
Doug Mac Kay
Study Guide
Final

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LECTURE FIVE: ADRENAL GLAND
\Æthere is an inner layer = adrenal medulla, and an outer layer = adrenal cortex
players
Æepinephrine = catecholamines
::acute stress response
::rapid effect for preparing fight v. flight
Æcortisol = glucocorticoid
::chronic stress hormone
::longer time to be released, but sustained/chronic effect
::has the ability to regulate glucose levels
ÆCRH = cortiotropin-releasing hormone
::brain neurotransmitter
::made from the adrenal gland
ÆACTH = trophic hormone
::melanocortin family
::all came from the same precursor gene (POMC ± gives ACTH and
upon splicing, can give multiple forms of the hormone)
*adrenal medulla = modified sympathetic ganglia
Æcatecholamines
Æepinephrine
*adrenal cortex = steroid factory
Æglucocorticoids {cortisol}
Æmineralcorticoids {aldosterone}
Æsex steroids {testosterone}
Æadrenal gland is next to kidney
*aldosterone /mineralcorticoid = regulates mineral levels (Na+/K+)
*testosterone = in females, goes to ovaries and because of the presence of aromatose, creates estrogen
recall: epinephrine = adrenaline Æfight v. flight response
\Æprovides body with energy for an acute stress response
Ædifferent responses based on which receptors are activated
recall: sex steroids = modified from cholesterol by enzymes in certain tissues/cells
::testosterone movement to ovary + aromatase = estrogen
*Æsex hormones are derived from steroids
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((specific steroids synthesized in specific adrenal cortex zones))
region synthesis
medulla catecholamines
zona reticularis sex hormones
cortex zona fasciulata glucocorticoids
zona glomerulosa aldosterone
capsule
ADRENAL GLAND EFFECTS
Hormone
Mechanism
Function & Effect
Other Considerations
aldosterone
- recallLW¶VDVWHURLGKRUPRQHDQGDSURSHUW\RI
steroids is diffusibility
- (1) will diffuse into the cell and bind to its
receptor
- (2) favours movement of the complex to bind to
the responsive element of aldosterone, found on
DNA
- binding of complex does require a few co-
activators because binding of aldosterone to
receptor is insufficient to turn on the expression
of appropriate genes
leads to overproduction of genes
responsible for forming K+
channel or ATPase Na+/K+ pump
once the synthesis of these genes is
elevated, undergoes post-
transciptional modifications to give
proper channel and pump activity
because of the presence and
elevation of the quantity of the
pumps, the next flow of minerals
from the external environment ±
the lumen, to the internal
environment ± the blood, is a net
increase of [sodium]
o steroid hormone
o mineralcorticoid = regulates Na+ and
K+ levels in the blood
o the use of co-activators presents
multiple site for regulation, initiation
and inhibition of the rate of target
protein synthesis
o knowing the effect, can predict that
when there is a low [sodium] in the
body there will be a release of
aldosterone to maintain mineral
homeostasis
o the influx of sodium from the lumen
is done through the exchange of K+
and ATP
o this sodium gradient must be kept
constant so K+ channel must
continually excrete K+ in the lumen
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