Adrenal Gland Flashcards
Why adrenal glands are important?
The adrenal glands are important in the synthesis and regulation of key hormones.
They play a crucial role in water and electrolyte homeostatsis, as well as regulation of blood pressure, carbohydrate and fat metabolism, physiologic response to stress, and sexual development and differentiation.
The adrenal medulla secretes…
The adrenal medulla secretes the catecholamines epinephrine (also called adrenaline) and norepineprhine (also called noradrenaline), which are involved in regulation of the sympathetic nervous system.
The adrenal cortex consists of:
The adrenal cortex consists of three histologically distinct zones:
zona glomerulosa, zona fasciculata, and an innermost layer called the zona reticularis.
Whats the role of zone glomerulosa?
The zona glomerulosa is responsible for the production of the mineralocorticoids aldosterone, deoxycorticosterone, and 18-hydroxy-deoxycorticosterone.
Whtas the role of zone fasiciculata?
The zona fasciculata produces the glucocorticoid hormone cortisol.
The normal rate of cortisol production is approximately 8 to 15 mg/day.
Its production increases markedly during physiologic stress, such as during acute illness, surgery, or trauma.
Cortisol is converted in the liver to an inactive metabolite known as
cortisone.
What’s the role of zone reticularis?
The zona reticularis produces the androgens androstenedione, dehydroepiandrosterone (DHEA), and the sulfated form of dehydroepiandrosterone (DHEA-S).
Androstenedione and DHEA are converted to…
Androstenedione and DHEA are converted in the
periphery, largely to testosterone and estrogen.
What controls the adrenal hormone production?
Adrenal hormone production is controlled by the
hypothalamus and pituitary gland.
What happens when sufficient or excessive cortisol levels are reached?
Adrenal androgen same mechanism
When sufficient or excessive cortisol levels are
reached, a negative feedback is exerted on the
secretion of CRH and ACTH, thereby decreasing
overall cortisol production.
What does Adrenal insufficiency refer to?
Adrenal insufficiency generally refers to the inability of
the adrenal glands to produce adequate amounts of
cortisol for normal physiologic functioning or in times of
stress.
Classification of Adrenal Insufficiency
The condition is usually classified as primary,
secondary, or tertiary
When are these insufficiencies diagnosed?
Primary adrenal insufficiency usually is diagnosed in the
third to fifth decades of life, whereas secondary adrenal
insufficiency is commonly detected during the sixth
decade.
Prevalence of Adrenal Insufficiency?
More in women
What causes A.Insufficiency?
It occurs from destruction of the adrenal cortex, usually from an autoimmune process.
What causes Secondary adrenal insufficiency ?
Secondary adrenal insufficiency occurs as a result of a
pituitary gland dysfunction whereby decreased production and
secretion of ACTH leads to a decrease in cortisol synthesis.
What causes Tertiary adrenal insufficiency ?
Tertiary adrenal insufficiency is a disorder of the
hypothalamus that results in decreased production and release of CRH, which, in turn, decreases pituitary ACTH production and release.
What causes Acute adrenal insufficiency (i.e., adrenal crisis)?
Acute adrenal insufficiency (i.e., adrenal crisis) results from the body’s inability to increase endogenous cortisol sufficiently during periods of excessive physiologic stress.
A. Insufficiency signs and symptoms
weakness and fatigue requiring rest
periods, gastrointestinal symptoms, weight loss, and hypotension.
Association with A.Insufficiency
Patients with autoimmune adrenal insufficiency may have other autoimmune disorders such as type 1 diabetes mellitus and autoimmune thyroiditis.
• Dehydration, hypovolemia, and hyperkalemia (in primary adrenal insufficiency only).
• Decreased serum sodium and chloride levels. • Increased serum blood urea nitrogen (BUN) and creatinine owing to dehydration.
• Hyperpigmentation of skin.
• Personality changes (irritability and restlessness)
• Loss of axillary and pubic hair in women owing to decreased androgen
production.
• Blood count abnormalities.
Laboratory Test for Chronic A.Insufficiency
Decreased basal and stress-induced cortisol levels. • Decreased aldosterone level (in primary adrenal
insufficiency only). • Lack of increase in cortisol and aldosterone level after ACTH stimulation.
Diagnostic Tests for Adrenal Glands
Computed tomography (CT) or magnetic resonance
imaging (MRI).
The presence of anti-adrenal antibodies.
TTT for A. insuffciency?
Lifelong glucocorticoid replacement therapy may be necessary for patients with adrenal insufficiency, and mineralocorticoid
replacement therapy usually is required for those with
Addison’s disease.
Whats prescribed for Chronic A. Insufficiency
Hydrocortisone often is prescribed because it most closely resembles endogenous cortisol (with its relatively high mineralocorticoid activity and short half-life) and allows the design of regimens that simulate the normal circadian cycle.
What are the immediate goals of Acute A.Insufficiency?
The immediate treatment goals are to correct volume depletion, manage hypoglycemia, and provide glucocorticoid replacement.
