Term
| What are the three layers of the Adrenal Cortex? |
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Definition
Zona Glomerulosa
Zona Fasiculata
Zona Reticularis |
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Term
In which layer of the adrenal cortex is aldosterone synthesized?
Where is cortisol synthesized? |
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Definition
Zone Glomerulosa
Zona Fasciculata and Reticularis |
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Term
| What is the site for epinephrine synthesis? |
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Definition
| Chromaffin cells in the adrenal medulla |
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Term
| What are the three classes of steroids? |
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Definition
1. Glucocorticoids
2. Mineral Corticoids
3. Sex Steroids |
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Term
| Most of the enzymes that are responsible for cholesterol synthesis are ___________. |
|
Definition
|
|
Term
| What is the role of Cholesterol Side Chain Cleavage Enzyme? |
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Definition
| It turns C27 Cholesterol into Pregnenolone |
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|
Term
| Where is 17α-hydroxylase not present in significant quantity? |
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Definition
| Zona Glomerulosa. This is why cortisol is produced in the Fasciculata and Reticularis. |
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Term
| What does cortisol bind to in the circulatory system? |
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Definition
| CBG - Cortisol Binding Globin |
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Term
| T/F: Cortisol is freely soluble in plasma. |
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Definition
|
|
Term
| What is the role of cortisol? |
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Definition
| It pays a major role in the conversion of protein into glycogen, supporting a catabolic reaction. It antagonizes insulin actions. It increases Ca2+ excretion and bone resorption. Essentially decreases Ca2+ levels. |
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|
Term
| What is the effect of cortisol in the kidneys? |
|
Definition
| Increases glomerular filtration and increases water excretion. Increases Ca2+ and phosphate excretion. |
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Term
| What are the hormonal controls of cortisol? |
|
Definition
Hypothalamus: CRH
Anterior Pituitary: ACTH
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|
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Term
| What receptor does ACTH bind to? |
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Definition
| It binds to the melanocortin-2 receptor expressed in the cortex in the zona fasciculata and reticularis. |
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|
Term
| What is the feedback related to cortisol? |
|
Definition
ACTH feedback inhibits on the hypothalamus diminishing CRH release.
Cortisol feedback inhibits ACTH and CRH receptors in the anterior pituitary. |
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|
Term
| When is the peak release of cortisol? |
|
Definition
|
|
Term
| What is the major function of Aldosterone? |
|
Definition
| Major mediator of salt balance and extracellular volume. |
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|
Term
| T/F: Zona Glomerulosa cells exhibit large amounts of 17alpha-hydroxylase. |
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Definition
| False. They exhibit very little. That is why cortisol is not synthesize in these cells. |
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|
Term
What is the major enzyme for Aldosterone synthesis?
Where is it typically found? |
|
Definition
Aldosterone Synthase
In the mitochondria of the glomerulosa cells |
|
|
Term
| What are the regulators of Aldosterone? |
|
Definition
Major: K+, and Angiotensin II
Minor: ACTH |
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|
Term
| T/F: The mineracorticoid receptor in the kidney binds both Cortisol and Aldosterone. |
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Definition
|
|
Term
| How does Aldosterone maintain higher effect on mineralcorticoid receptors in the kidney despite the larger concentration of cortisol? |
|
Definition
| Cortisol, in the kidney, is altered by 11beta-hydroxysteroid dehydrogenase, which converts cortisol into cortisone which exhibits low affinity for the mineracorticoid receptors in the kidneys. |
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|
Term
What is the effect of the following on Aldosterone?
Angiotensin II
Increased K+
ACTH |
|
Definition
| They all increase the amount of Aldosterone secreted. |
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|
Term
| What is the overall effect of Aldosterone on the kidneys with respect to Na+ and K+? |
|
Definition
Na+ is reabsorbed
K+ is excreted into the urine |
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|
Term
What is Addison's Disease?
What is the cause?
What are the symptoms? |
|
Definition
Primary Adrenal Cortex insufficiency; complete destruction of the adrenal cortex due to autoimmune disease, infection, and cancer.
Hypotension, Low Na+, High K+, general muscle weakness |
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|
Term
What is Cushing Snydrome?
What is the cause?
What are the symptoms? |
|
Definition
Chronic glucocorticoid production.
ACTH excess from pituitary tumor. Can be caused by excessive glucocorticoid administration in patients suffering from asthma, arthritis, lupus...
Thin arms and legs from protein catabolism. Moon faces, Loss of collagen in skin. |
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|
Term
| Where is epinephrine and norepinehprine synthesized and released? |
|
Definition
| In the chromaffin cells, derived from neural crest cells, of the Adrenal Medulla. |
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|
Term
| What are chromaffin cells analogous to? |
|
Definition
| Post-Ganglionic Sympathetic |
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|
Term
| What is the feedback on the neuroendocrine cells of the adrenal medulla? |
|
Definition
|
|
Term
| What is the first tissue that is exposed to the glucocorticoids and mineralcorticoids of the Adrenal Cortex? |
|
Definition
| The Adrenal Medulla, since veins perfuse directly from cortex to medulla. |
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Term
| What is the substrate for the synthesis for Catechoamine? |
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Definition
|
|
Term
| What is the enzyme responsible for turning Tyrosine into Dopa? |
|
Definition
|
|
Term
| What increases norepinephrine and epinephrine release? |
|
Definition
| Sympathetic stimulation and ACTH |
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|
Term
| What is the most critical role of catecholamines? |
|
Definition
| To ensure that there is sufficient glucose available for the CNS |
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|
Term
| What receptors do catecholamines bind to? |
|
Definition
| Alpha and Beta Adrenergic Receptors which are G-Protein coupled receptors |
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