Adrenal Endocrine Flashcards
How are the adrenal glands developed?
Two distinct glands that form one organ during development
The adrenal medulla is derived from _________, and the cortex is derived from ____________.
Neural crest cells; mesothelial
Which part of the adrenal gland is part of the nervous system?
Medulla (Sympathetic)
What two hormones are released by the adrenal medulla?
Epinephrine and norepinephrine
The adrenal medulla acts as a sympathetic ganglion. What takes the place of postsynaptic neurons with axons?
Chromaffin cells release epinephrine (80%) and norepinephrine (20%) into the blood
Beta-adrenergic receptors have a greater affinity for __________ while alpha-adrenergic receptors have a greater affinity for _________.
Epinephrine; norepinephrine
Since the adrenal medulla endocrine response is blood born, how might it effect the body differently than a typical neural response?
May last longer
What organs and tissues are reached by the adrenal medulla that do not have neural circuits?
Liver, skeletal muscle, and fat
What is the main action of epinephrine from the adrenal medulla?
Increase availability of metabolic fuel via lipolysis, glycogenolysis, and gluconeogenesis
What are the three zones of the adrenal cortex from outer to inner?
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
T/F: Most steroid synthesis and secretion in the adrenal cortex is stimulated by ACTH.
True
Which zone produces aldosterone?
Zona glomerulosa
What is the principle action of aldosterone?
Stimulate Na and H2o retention by the kidney to maintain blood volume and pressure
T/F: Active aldosterone will cause an increase in urinary excretion of K and H
True
How does aldosterone act in the cell?
Creates an aldosterone-receptor complex which binds to DNA
What do the cellular protein products of aldosterone do to the cell?
Opens sodium channels from tubular fluid while producing more ATP to activate more Na-K pumps to push more sodium out into the blood
T/F: ACTH is the main regulator for secretion of aldosterone.
FALSE
What factors stimulate aldosterone secretion?
- Increase in Angiotensin II
- Increase in plasma K
- Decrease in plasma pH
- Low blood pressure
When blood pressure is low the adrenal cortex will release ___________ from the zona ____________.
Aldosterone; glomerulosa
What is the major glucocorticoid?
Cortisol
What zone of the cortex produces cortisol?
Zona fasciculata
What is the major effect of cortisol?
Increase metabolic fuel availability and use in tissues
Cortisol has a negative feedback action on _____ and _____.
CRH and ACTH
What are the effects of cortisol on the various organs and tissues it acts on?
Liver: increase gluconeogenesis
Muscle: increase proteolysis
Fat: increase lipolysis
What systemic actions does cortisol have?
- Decrease glucose uptake
- Immune and inflammatory response
- Decrease growth and reproductive function
Which zone are sex steroids secreted from in the cortex?
Zona reticularis
The two major sex steroids (androgens) are _________ and __________.
DHEA and androstenedione
Which androgen has relatively weak androgen action but is a precursor for other sex steroids?
DHEA
Peripheral concentrations of ________ is a good indicator for overall activity of the adrenal cortex.
DHEA
_________ provides a non-gonadal source of testosterone and estradiol.
Androstenedione
When is DHEA a crucial source for reproductive steroids?
Pre-puberty and post-menopause
T/F: Adrenal sex steroids are stimulated by the same hormones as gonadal sex steroids.
FALSE
ACTH stimulates adrenal sex steroids
What is the stress axis?
Hypothalamus -> anterior pituitary -> adrenal cortex
A stress response is a response to a stressor that stimulates hypothalamic ________ neurons and inputs to the _______.
CRH; sympathetic nervous system
During the stress response, increased secretion of ___________ increases the availability of metabolic fuel and other functions.
Cortisol
Cortisol has a __________ response and inhibits the actions of _________.
Delayed; insulin
What is the primary hormone involved with the stress response?
Epinephrine
T/F: The stress response involves a rapid response involving skeletal muscle stimulation and inhibition.
FALSE
Smooth muscle
What are the three primary goals of the stress response?
- Maintain blood pressure
- Mobilize and increase availability of metabolic fuel
- Inhibit non-essential functions
How is the stress response shut off?
- Removal of stressor
2. Negative feedback of cortisol on CRH and ACTH
What are the problems that can relate to a chronic stress response leading to a long period of elevated cortisol levels?
- Catabolism of glucose substrates
- Anti-inflammatory and anti-immune effects
- Increased blood lipids -> atherosclerosis and hypertension
T/F: There is evidence that certain viral infections can be made worse with activation of the stress response.
True
What are some symptoms of adrenal insufficiency/Addison’s Disease?
- Low cortisol and high ACTH
- Weakness, decreased appetite
- Low blood pressure
- Low glucose
- Hyperpigmentation
How should adrenal insufficiency be treated?
Exogenous glucocorticoids and/or dietary control
What is the typical cause of hypercortisolinemia/Cushing’s Disease?
Pituitary tumor
T/F: Cushing’s disease will lead to an increased basal concentrations of cortisol.
TRUE
What are some symptoms of Cushing’s Disease?
- Excessive tissue catabolism
- Diabetes like symptoms
- High blood pressure
- Impaired immune function
