are located on top of each kidney Adrenal Glands Copyright 2014 John Wiley amp Sons Inc All rights reserved Cortex outer bulk of gland 75 glandular tissue Medulla inner nervous tissue SNS ID: 743256
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Slide1
Adrenal GlandsSlide2
The
adrenal glands (suprarenal glands) are located on top of each kidney.
Adrenal Glands
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide3
Cortex
(outer) – bulk of gland (75%); glandular tissueMedulla
(inner) – nervous tissue; SNS
Adrenal Gland – 2 Glands in 1Slide4
Glandular vs. Nervous tissue
Remind you of another endocrine gland??
Blood flows from outside of adrenals inward
Cortex vs. MedullaSlide5
Cortex
- divided histologically into 3 regions:
ZG - “salt”MineralcorticoidsZF – “sugar”
GlucocorticoidsZR – “sex”Gonadocorticoids
Adrenal Cortex ZonesSlide6
The zona glomerulosa secretes:
Mineralocorticoids
- used to regulate mineral homeostasis (electrolytes), Na2+ K+AldosteroneThe zona
fasciculata secretes:Glucocorticoids -
affect glucose homeostasis
Cortisol
The zona reticularis secretes:
Weak
androgens
DHEA
, androstenedione
Adrenal Cortex HormonesSlide7
Aldosterone
is the major mineralocorticoid.
Regulates sodium (Na2+) and potassium (K+) homeostasis.
Controlled by renin-angiotensin-aldosterone (RAA) pathway A.k.a. Renin Angiotensin System (RAS)
Zona Glomerulosa -
MineralcorticoidsSlide8
Renin-Angiotensin-Aldosterone (RAA) Pathway
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide9Slide10Slide11
Stimulated by ACTH
Secretion of cortisol is regulated by
negative feedback
.Glucocorticoids help control:Protein breakdown
Glucose formation
Lipolysis
Resistance to stress
Inflammation
Immune responses
Zona
Fasciculata
- Glucocorticoids
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide12
Mostly
permissive to actions of other hormones
.
Epi is ineffective w/out cortisol
Under stress, w/out
glucocorts
, there is vascular collapse.
Maintain cardiac output; increase arteriolar tone; decrease endothelial permeability; maintain normal vascular resistance
Maintains normal BP (angiotensin II)
Modulate emotional tone, wakefulness; memory
High cortisol will
↓
muscle mass and bone formation
Inhibit inflammatory and immune response
Facilitate maturation of the fetus
Develops fetal enzyme systems
Growth and development
GlucocorticoidsSlide13Slide14
Glucocorticoid
Feedback
Loop
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.Slide15
Dehydroepiandrosterone
(DHEA) – major androgen secreted.
In males, after puberty the hormone testosterone
is secreted in much larger quantities so DHEA has virtually no effect.In females, DHEA and other adrenal androgens play a major role in
promoting libido
and are converted to
estrogens
.
In menopausal women, all female estrogens come from adrenal androgens.
Zona Reticularis -
GonadocorticoidsSlide16
Stimulated by sympathetic preganglionic neurons of the autonomic nervous system (ANS).
Chromaffin cells
store and secrete 2 catecholamines:
epinephrine (adrenaline) norepinephrine (noradrenaline).Both of which are involved in the
fight-or-flight response
.
Adrenal MedullaSlide17
Sympathoadrenal
activity is enhanced under conditions of hyperthyroidism and depressed under conditions of low levels of thyroid hormones.
Major symptoms of patients with thyroid dysfunction relate to functional alterations of those organs regulated by the sympathetic nervous system.
Catecholamines
& Thyroid HormoneSlide18