Endocrine Emergencies 2 Flashcards
Adrenal Medulla
- Controlled by?
- When stimulated it secretes?
2 Adrenal Cortex
- Three zones: What are they?
- What do they secrete?
Adrenal Medulla
- Controlled by nervous system
- When stimulated secretes epinephrine and norepinephrine into adrenal veins
Adrenal Cortex
- Glomerulosa: mineralocorticoids… aldosterone
- Fasciculata: glucocorticoids… cortisol
- Reticularis: sex hormones
Adrenocorticotropic Hormone ACTH
What does it do?
Primarily what?
Remember, -tropin or -tropic means to stimulate.
Therefore, adrenocorticotropic means “to stimulate the adrenal cortex”
Function: Stimulates synthesis and secretion of adrenocortical hormones (cortisol, androgens, and aldosterone)
ACTH primarily stimulates cortisol
Describe the normal ACTH physiology
What does cortisol stimulate? 4
1) Gluconeogenesis
2) Protein mobilization
3) Fat mobilization
4) Stabilizes lysosomes
Adrenal Insufficiency vs Crisis
- Adrenal Insufficiency is what?
- What kind of disease is this?
- Adrenal Crisis is what?
- What kind of condition is this?
Adrenal Insufficiency
- Failure of adrenal glands to produce essential BASAL secretion of steroids
- Insidious wasting disease
Adrenal Crisis
- Failure to RESPOND to the increased demands caused by stress or SUDDEN INABILITY to secrete essential steroids
- Life-threatening condition
Nova’s likely diagnosis:
Adrenal insufficiency, of which there are two forms:?
- Primary adrenal insufficiency (Addison’s disease)
- Secondary adrenal insufficiency
Adrenal insufficiency?
- Primary adrenal insufficiency (Addison’s disease) results from?
- Secondary adrenal insufficiency results from?
Primary adrenal insufficiency (Addison’s disease)
- Results from destruction or dysfunction of the adrenal cortex
Secondary adrenal insufficiency
- Results from inadequate stimulation of adrenal cortex by ACTH (***By far the most common cause is chronic administration of exogenous steroids!)
Describe how the adrenal pathway changes in primary adrenal insufficiency?
What would happen to the adrenal pathway with exogenous administration of corticosteriods?
Decreased blood pressure?
Decreased cortisol:
- Cortisol up-regulates alpha1-adrenergic receptors on vascular smooth muscle (what does stimulation of the alpha1 receptors do again?) so a decreased amount would…? 3
Decreased aldosterone:
- Aldosterone increases Na reabsorption by renal cells, leading to increases in extracellular fluid volume and blood volume, venous return, cardiac output, and arterial pressure. Therefore a decrease in aldosterone would…? 2
1.
- Cause vasodilation and
- decrease in peripheral vascular resistance
- and decreased BP
2.
- More NA+ to be excreted in the urine and also more water excretion.
- decreased blood pressure
Adrenal Insuffieciency
Pulse rate increase?
Compensatory mechanisms as a result of: 4
- Decreased volume
- With decreased volume we have decreased arterial pressure
- ➔ baroreceptor reflex
- ➔ increased sympathetic outflow and therefore an increase in heart rate
Decreased blood glucose?
Decreased cortisol:
One action of cortisol is to increase blood glucose concentration by promoting gluconeogenesis and decreasing glucose uptake by the tissues and therefore a decrease in cortisol would…?
Decrease blood glucose levels
Hyperkalemia?
Decreased aldosterone:
In addition to stimulating Na reabsorption, aldosterone stimulates K secretion by the renal principal cells and therefore a decrease in aldosterone would…?
inhibit K secretion
Late Distal Tubule/Collecting Duct Area
- The principal cells reabsorb what? 2 And secrete what?
- Aldosterone exerts its effects by increasing the function of the what?
Hyponatremia?
Decreased aldosterone
Aldosterone increases Na reabsorption by renal principal cells. Therefore, with decreased aldosterone we would have…?
Increased Na and water excretion
In contrast to indolent and progressive course of chronic adrenal insufficiency, ***adrenal crisis presents as a life-threatening emergency in which the primary manifestation is what??
hypotension