Physio L6 Adrenal Cortex Flashcards

1
Q

Aldosterone binds to which plasma protein?

A

Steroid-binding protein (SBP)

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2
Q

What are the target cells of Aldosterone?

A

Principal cells of DCT and CT

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3
Q

Name of aldosterone receptor? What is the final response?

A

Mineralocorticoid receptor (MR), synthesis of Aldosterone-induced proteins (increase Na+ reabsorption)

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4
Q

Effect of aldosterone on H+, which cells are involved?

A

Increase H+ excretion in intercalated cells of DCT & CT

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5
Q

What are the secondary effects of aldosterone?

A

1) Exocrine glands (mammary, gastric, sweat, salivary): increase Na+ reabsorption and excretion of K+
2) Small intestine: increase Na+ absorption, decrease K+ absorption.

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6
Q

What is the major regulator of Aldosterone secretion?

A

K+ concentration (1% increase increases Aldosterone by direct action on ZG)

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7
Q

What are the secondary regulators of aldosterone secretion?

A

1) Na+ concentration (hyponatremia—> secretion); direct effect on ZG
2) RAAS (stimulates secretion)
3) ECF volume
4) ACTH (mild stimulation)

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8
Q

What is Conn’s syndrome? What causes it?

A

Primary hyperaldosteronism: caused by adrenal adenoma or bilateral hyperplasia of ZG

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9
Q

Clinical presentation of Conn’s?

A

1) Reduced K+ (muscle weakness, ECG abnormalities, nephropathy)
2) Excessive loss of H+ —> metabolic alkalosis
3) Less ionized Ca2+ —> Tetany
4) No LL edema

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10
Q

Differentiate between primary and secondary hyperaldosteronism

A

Primary —> no LL edema due to “aldosterone escape phenomenon”
Secondary —> Edema present

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11
Q

Explain the Aldosterone escape phenomenon and its causes

A

It is the escape of kidney tubules from Na+ retention in-spite of excess aldosterone.
It is due to expansion of ECF volume leading to release of ANP which will cause loss of Na+ and H2O while also inhibiting RAAS.

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12
Q

General features of cortisol

A

1) only 10% is free (80% binds SBP & 10% binds Albumin)
2) Aligned with circadian rhythm
3) Its essential for life (since its part of cortex, only medulla is non-essential)

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13
Q

What are the metabolic functions of Cortisol?

A

1) CHO: hyperglycemic (Increased liver gluconeogensis, decreased insulin sensitivity, inhibit glucose uptake)
2) Lipids: lipolytic (increase FFA)
3) Proteins: Catabolic except in Liver anabolic
4) Minerals: increase Na+ & H2O retention

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14
Q

What are the actions of cortisol on body systems?

A

1) CNS: Decreases REM sleep (insomina), causes excitability
2) CVS: Permissive effect on catecholamines (vasoconstriction—>increases BP)
3) Renal: Na+ & H2O retention, however it inhibits Aldosterone (hence can be used to for H2O removal)
4) GIT: increase HCL secretion (Peptic Ulcer)

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15
Q

What is the difference between cushing’s disease and syndrome?

A

Disease (secondary) is caused by Pituitary adenoma, while syndrome (primary) is caused by adenoma of ZF

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16
Q

Define Addison’s disease and its cause

A

It is the hypofunction of all adrenal cortex hormones caused by bilateral destruction by Autoimmune condition, tumor or TB

17
Q

What is a characteristic presentation other than the effects of hormone deficiency occurs on Addison’s?

A

Dark skin pigmentation due to increase ACTH (which has MSH like action)