S9) The Adrenal Glands & Disorders Flashcards Preview

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Flashcards in S9) The Adrenal Glands & Disorders Deck (51)
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Describe the macroscopic and microscopic structure of the adrenal glands


What are the three areas in the adrenal cortex?

- Zona glomerulosa

- Zona fasiculata

- Zona reticularis 


Identify and describe the hormones in the different regions of the adrenal cortex


Steroid hormones are lipid soluble.

Describe their formation and function

- Formation: synthesised from cholesterol in adrenal glands and gonads

- Function: bind to receptors of the nuclear receptor family to modulate gene transcription 


Provide five examples of steroid hormones

- Glucocorticoids

- Mineralocorticoids

- Androgens

- Oestrogens

- Progestins 


Corticosteroids exert their actions by regulating gene transcription. 

In six steps, outline this process

⇒ Corticosteroids readily diffuse across plasma membrane

⇒ Bind to glucocorticoid receptors

⇒ Binding dissociates chaperone proteins 

⇒ Receptor-ligand complex translocates to nucleus

⇒ Dimerisation with other receptors can occur

⇒ Receptors bind to GREs / other transcription factors 


Aldosterone is the most abundant mineralocorticoid. 

Describe its function and transport

- Transport: carrier protein (mainly serum albumin or transcortin)

- Function: central role in regulation of plasma Na+, K+ and arterial blood pressure


Aldosterone is a central component of renin-angiotensin-aldosterone system.

In light of this, explain its specific actions 

- Promotes expression of Na+/K+ pump increasing reabsorption in distal tubules and collecting ducts of nephron

- This influences water retention, blood volume & therefore blood pressure


Outline all the cellular and hormonal mechanisms involved in RAAS


What is hyperaldosteronism?

Hyperaldosteronism is a physiological state/condition wherein there is an excessive production of aldosterone


Distinguish between the two forms of hyperaldosteronism

Primary – defect in adrenal cortex (high aldosterone:renin ratio) 

- Secondary – over-activation of RAAS (low aldosterone:renin ratio) 


Identify two causes of primary hyperaldosteronism

- Bilateral idiopathic adrenal hyperplasia (most common)

- Aldosterone-secreting adrenal adenoma (Conn’s syndrome


Identify two causes of secondary hyperaldosteronism

- Renin producing tumour e.g. juxtaglomerular tumour (rare)

- Renal artery stenosis 


Identify 5 clinical signs of hyperaldosteronism

- High blood pressure

- Left ventricular hypertrophy

- Stroke

- Hypernatraemia

- Hypokalaemia


The treatment for hyperaldosteronism depends on its form.

Describe the possible options

- Aldosterone-producing adenomas removed by surgery

- Spironolactone (mineralocorticoid receptor antagonist) 


Cortisol is the most abundant corticosteroid & accounts for ~95% of glucocorticoid activity.

Describe its formation and transport

- Formation: synthesised and released by zona fasiculata in response to ACTH

- Transport: carrier protein in plasma (transcortin)


Cortisol is the most abundant corticosteroid & accounts for ~95% of glucocorticoid activity.

Describe its function and regulation

- Function: cortisol receptor exerts its actions by regulating gene transcription 

- Regulation: negative feedback to hypothalamus inhibits CRH & ACTH release



Cortisol can act in 6 different ways.

Identify these

- Increased proteolysis in muscle

- Increased lipolysis in fat

- Increased gluconeogenesis in liver 

- Resistance to stress

- Anti-inflammatory effects

- Depression of immune response 


Cortisol is useful medication for allergic reactions

Describe its anti-inflammatory effects

- Inhibits macrophage activity

- Mast cell degranulation


Explain the resistance of cortisol to stress

- Increased supply of glucose

- Raise BP by making vessels more sensitive to vasoconstrictors


Identify one use of cortisol due to its ability to depress the immune response

Cortisol is prescribed to organ transplant patients 


Outline the HPA axis


Explain how the glucocorticoid actions on metabolism lead to the following:

- Increased glucose production

- Breakdown of protein

- Redistribution of fat



What is Cushing's syndrome?

- Cushing’s Syndrome is a clinical condition arising due to chronic excessive exposure to cortisol 

- It leads to the re-distribution of fat especially in abdomen, supraclavicular fat pads, dorso-cervical fat pad, (buffalo hump), & on face (moon face)


Describe the aetiology of Cushing's syndrome in terms of its endogenous and exogenous causes


Identify some signs and symptoms of Cushing's syndrome

- Plethoric moon-shaped face

- Buffalo hump

- Abdominal obesity

- Purple striae

- Acute weight gain

- Hyperglycaemia

- Hypertension


Identify two examples of steroid drugs

- Prednisolone

- Dexamethasone 


Steroid drugs have anti-inflammatory & immunomodulatory effects, thus are used to treat inflammatory disorders.

Provide some examples of these conditions

- Asthma

- Inflammatory bowel disease

- Rheumatoid arthritis

- Other auto-immune conditions 


Describe the possible side effects due to steroid drugs

Side-effects are the same as the effects of higher levels of cortisol, plus can also have mineralocorticoid effects 


How might one stop steroid drug usage?

Steroid dosage should be reduced gradually and not stopped suddenly