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7/31/2019 Adrenal Gland Lecture 8-9
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Suprarenal Glands
Divided into two parts; each with separate
functions
Suprarenal Cortex
Suprarenal Medulla
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The Adrenal Cortex
Figure 25.9a
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C. The Adrenal Glands
Adrenal medulla
Adrenal cortexThree specific zones and each produces a specificclass of steroid hormone
Zona glomerulosa mineralocorticoids (Aldosterone)
Zona fasciculata glucocorticoids ( Cortisole)Zona reticularis - androgens
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Hormones of the Adrenal CortexHormones of the Adrenal Cortex
Slide 9.29aCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Glucocorticoids (including cortisone andcortisol)
Produced in the middle layer of the adrenalcortex
Promote normal cell metabolism
Help resist long-term stressors
Released in response to increased bloodlevels of ACTH
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Hormones of the Adrenal CortexHormones of the Adrenal Cortex
Slide 9.29bCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Sex hormones
Produced in the inner layer of the adrenalcortex
Androgens (male) and some estrogen(female)
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Functions of mineralocorticoids
Aldosterone exerts the 90% of the mineralocorticoid
activity. Cortisol also have mineralocorticoid activity, but
only 1/400th that of aldosterone
Aldosterone increases renal tubular (principal cells)
reabsorption of sodium & secretion of potassium
Excess aldosterone ECF volume & arterial pressure, but
has only a small effect on plasma sodium concentration
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Excess aldosterone causes hypokalemia & muscle
weakness, & too little aldosterone causes
hyperkalemia & cardiac toxicity
Excess aldosterone increases tubular (intercalatedcells) hydrogen ion secretion, with resultant mild
alkalosis
Aldosterone stimulates sodium & potassium
transport in sweat glands, salivary glands, &
intestinal epithelial cells
Functions of mineralocorticoids
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Effect of cortisol on protein metabolism
Reduction of protein storage in all cells except
those of liver protein catabolism & protein
synthesis Cortisol increases liver & plasma proteins
Mobilizes aminoacids from non hepatic cells, thus
increase blood amino acid level.
amino acid transport to liver cells & transport
of amino acids into other cells
Functions of glucocorticoids
7/31/2019 Adrenal Gland Lecture 8-9
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Hormones of the Adrenal CortexHormones of the Adrenal Cortex
Slide 9.28bCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 9.10
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Renin-angiotensin-aldosterone axis Principal factor
controlling Ang II levelsis renin release.
Decreased circulatingvolume stimulates renin
release via: Decreased BP (symp
effects on JGA).
Decreased [NaCl] atmacula densa (NaClsensor)
Decreased renalperfusion pressure(renal baroreceptor)
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REGULATION OF CORTISOL
SECRETIONHYPOTHALAMUS
CRH
ANTERIOR PITUITARY
ACTH
ADRENAL CORTEX
TARGET ORGANS
CORTISOL
STRESSDIURNAL
RHYTHM+
+-
-INCREASED
BLOOD GLUCOSE
BLOOD AA
BLOOD FATTY ACIDS
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Pathway of RAAS
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Figure 6.12b
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Atrial natriuretic peptide
Decreased blood pressure
stimulates renin secretion
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Adrenal
cortexCorticosterone
Angiotensinogen
(Lungs)
(considered volume receptors)
Angiotensin I
Converting
enzymes
Angiotensin II(powerful vasoconstrictor)Angiotensin III(powerful vasoconstrictor)
Renin-Angiotensin System:
N.B. Aldosterone is the main regulator of Na+ retention.
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Renin-Angiotension-Aldosterone System
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Na+
Reabsorption
Angiotensisn II can raise
blood pressure by:
vasoconstrictoreffects.
stimulating
aldosterone secretion.
Insert fig. 17.26
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nephron
low
Blood Osmolarity
blood osmolarity
blood pressure
ADH
increasedwater
reabsorption
increasethirst
renin
increasedwater & saltreabsorption
high
pituitary
angiotensinogenangiotensin
nephronadrenal
gland
aldosterone
JuxtaGlomerularApparatus (JGA)
Ooooooh!Zymogen!
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Hormones of the Adrenal MedullaHormones of the Adrenal Medulla
Slide 9.30Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Produces two similar hormones(catecholamines)
Epinephrine
Norepinephrine
These hormones prepare the body todeal with short-term stress
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Effects of Epinephrine
Gets you ready to fight or run
Heightens your senses, tenses your muscles,
openings breathing passages, etc.
In response to stress
Take less than 30 seconds to kick in and last
several minutes
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C. Disorders of the Adrenal Gland
1. Hypoaldosteronism
loss of water/Na+
Addisons disease low aldosterone & cortisol
2. Hyperaldosteronism
3. Cushings syndrome
hypersecretion of cortisol,androgens,aldosterone
15 4 Adrenal glands
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Adrenal glands can malfunction
Cushing syndrome hypersecretion ofglucocorticoids by the adrenal cortex characterized
by weight gain in the trunk of the body but notarms and legs
15.4 Adrenal glands
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Cushings Disease
Proximal muscle
wasting & weakness
Osteoporosis
Glucose intolerance
HTN, hypokalemia
Thromboembolism
Depression, Psyc
Infection
Glaucoma
15 4 Adrenal glands
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Adrenal glands can malfunction
Addisons disease hyposecretion of
glucocorticoids by the adrenal cortex
characterized by bronzing of the skin
15.4 Adrenal glands