Title: The Adrenal Glands Part 1
1The Adrenal GlandsPart 1
- ERM Lecture
- 4/ 2007
- Steven Chessler M.D., Ph.D.
2- Anatomy of the adrenal glands
- Hypothalamic Pituitary Adrenal Axis
- Renin-angiotensin system
- Steroid hormones
- Congenital adrenal hyperplasia (CAH)
- Adrenal disorders
- Adrenal hyperfunction (Cushings syndrome)
- Adrenal insufficiency (Addisons disease and
others) - Pheochromocytoma (adrenal medulla)
3The Adrenal Glands
4Adrenal Cross Section
5Zones of the Adrenal Cortex
6Adrenal Zonation and Vasculature
-blood flow -steroid gradient
7Overview Hypothalamic-Pituitary-Adrenal (HPA)
Axis
8PROCESSING OF POMC IN THE PITUITARY ACTH (and
MSH, beta-endorphin)
9Addisons Disease effect of MSH activity
10The HPA Axis and the Stress Response
- Glucocorticoids trigger the release of sugar from
body stores to provide quick energy for fight or
flight. - Injected into the brain in animals, CRH causes
arousal and behavioral changes suggesting fear or
emotional distress. - Beta-endorphin (like ACTH a part of POMC)
partially antagonizes these responses.
11- My mind sent a message to my hypothalamus, and
told it to release the hormone CRF into the short
vessels connecting my hypothalamus and pituitary
gland. - The CRF inspired my pituitary gland to dump the
hormone ACTH into my bloodstream. My pituitary
had been making and storing ACTH for just such an
occasion. - And some of the ACTH in my bloodstream reached
the outer shell of my adrenal gland, which had
been making glucocorticoids for emergencies.
My adrenal gland added the glucocorticoids to my
bloodstream. They went all over my body,
changing glycogen into glucose. Glucose was
muscle food. It would help me fight like a
wildcat or run like a deer. -
- -Kurt Vonegut, Jr., Breakfast of Champions
12Adrenal medulla also participates in stress
response
Adrenal Gland Glomerulosa Fasciculata Reticularis
Medulla
1. Efferent sympathetic inflow 2. Cortisol-rich
blood ? epinephrine release
Kidney
BDA
13Cortisol and epinephrine (adrenaline)
- Fight or flight hormones
- Secretion increased 4-5 fold with marked
stress -emotional or physical - Catabolic
- Support/ defend blood pressure
- Supply energy, e.g. glucose fatty
acids -usually at the expense of anabolic
processes, e.g. protein synthesis, fuel
storage and growth
14Source of plasma catecholamines
- Norepinephrine
- Almost all from sympathetic nerve fibers
- Epinephrine
- Almost all from adrenal medulla (85)
BDA
15Physiological Effects of Glucocorticoids
16(No Transcript)
17The Hypothamic-Pituitary-Adrenal Axis
18- Anatomy of the adrenal glands
- Hypothalamic Pituitary Adrenal Axis
- Renin-angiotensin-aldosterone system
(Kidney-Adrenal Axis) - Steroid hormones
- Congenital adrenal hyperplasia (CAH)
- Adrenal disorders
- Adrenal hyperfunction
- Adrenal insufficiency
- Pheochromocytoma (adrenal medulla)
19Components of RAA axis
- Renin
- Acts to start cascade
- Angiotensin (II)
- Aldosterone
BDA
(slide by Brad Anawalt, M.D.)
20Function of R-A-A axis
- Responds to changes in blood pressure sensed at
the kidney - ? body Na content and blood volume
- K homeostasis
-
(slide by Brad Anawalt, M.D.)
21Glomeruli
(Modified from Ham AW. Histology. Philadelphia
JB Lippincott, 1969. by A. Dubrow and L.
Desimone)
22Glomeruli
Renal sympathetic nerves
U
JG cells
Efferent arteriole
Afferent arteriole
(slide by Brad Anawalt, M.D.)
23Stimulators of Renin Release
- ? sympathetic/adrenergic activity
- ? renal perfusion pressure
-
- ? serum K
- ? urinary lumen Na , macula densa
(B. Anawalt, M.D.)
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25Angiotensin II increases blood pressure
- vasoconstriction
- - (direct effect on BP)
- aldosterone
- - (indirect effect on BP)
BDA
26Aldosterone
BDA
27Renin-Angiotensin-Aldosterone Axis
?
blood volume UNa near macula densa
BDA
28Summary function of R-A-A axis
- Initiate cascade to defend blood pressure
- (renin)
- ? body Na content and blood volume
- (aldosterone)
- ? arterial BP
- (aldosterone angiotensin II )
- K homeostasis
- (aldosterone)
(slide by Brad Anawalt, M.D.)
2911b-Hydroxysteroid Dehydrogenase in
Aldosterone-Sensitive Tissues Modulation of
Cortisol Levels
11bHSD2
- Cortisol binds mineralacortidoid receptor
- Impaired 11bHSD2 apparent mineralacorticoid
excess -example licorice - Synthetic glucorticoids lower mineralacorticoid
activity
30- Anatomy of the adrenal glands
- Hypothalamic Pituitary Adrenal Axis
- Renin-angiotensin system
- Steroid hormone biosynthesis
- Congenital adrenal hyperplasia (CAH)
- Adrenal disorders
- Adrenal hyperfunction (Cushings syndrome)
- Adrenal insufficiency (Addisons disease and
others) - Pheochromocytoma (adrenal medulla)
31(No Transcript)
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33CAH 21-Hydroxylase Deficiency
34CAH 21-Hydroxylase Deficiency
- Salt-Wasting - severe hypotension often present
from birth due to mineralocorticoid deficiency. - Simple virilizing form less severe
mineralocoritcoid deficiency. - Nonclassical, late childhood and adult-onset
form - Presents as androgen excess in females.
May resemble Polycyctic Ovarian
Syndrome. -hirsutism, acne, menstrual
irregularity.
35Ambiguous Genitalia in Congenital Adrenal
Hyperplasia
36Neonatal Screening
37ACTH Stimulation test for 21-Hydroxylase
deficiency
38- Anatomy of the adrenal glands
- Hypothalamic Pituitary Adrenal Axis
- Renin-angiotensin system
- Steroid hormones
- Congenital adrenal hyperplasia (CAH)
- NEXT SESSION
- Adrenal disorders
- Adrenal hyperfunction (Cushings syndrome)
- Adrenal insufficiency (Addisons disease and
others) - Pheochromocytoma (adrenal medulla)