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BDS 2: Foundation Basic Sciences > L6 Adrenal Glands > Flashcards

L6 Adrenal Glands Flashcards

1
Q

Where are the adrenal glands located?

A

Pyramid shaped structure above each kidney.

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2
Q

Describe the structure of the adrenal glands.

A
  • Gland enclosed in a fibrous capsule
  • Adrenal medulla (inner layer)
  • Adrenal cortex (3 layers)
  • Rich blood supply directly from the aorta
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3
Q

Which structures are in control of the medulla and cortex?

A
  • Cortex is under the control of the anterior pituitary gland
  • Medulla is not under hormonal control and is therefore not a true endocrine gland
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4
Q

Describe the structure of the adrenal medulla.

A
  • Modified part of the symapthetic nervous system
  • Inner layer of the gland
  • Contains chromaffin cells which release adrenaline and noradrenaline when depolarised
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5
Q

What hormones are secreted from the adrenal medulla?

A

Secretes catecholamine hormones:

  • Adrenaline (80%)
  • Noradrenaline (20%)
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6
Q

What are the functions of catecholamines?

A

Prepares the body for acute stress (fight or flight).

Increase blood pressure, bladder weakness, increased heart rate, dry mouth, light headedness, sweating.

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7
Q

What are the cardiovascular effects of adrenaline?

A
  • Increased heart rate and stroke volume
  • Increased systolic blood pressure
  • Vasodilation of coronary and skeletal muscle BVs
  • Vasoconstriction of BVs to non-essential tissues e.g. GI tract, skin, kidneys
  • Bronchodilation to increase oxygen uptake
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8
Q

What are the metabolic effects of adrenaline?

A
  • Metabolic rate increases
  • Liver converts glycogen to glucose
  • Increased energy for immediate use
  • Blood flow changes, reduces digestive system activity and urine output
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9
Q

What are beta blockers?

A

Drugs which suppress the action of adrenaline by blocking beta receptors, used to treat hypertension.

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10
Q

What is the main function of the adrenal cortex and its hormones?

A

To deal with long-term stress e.g. exam anxiety.

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11
Q

What are the 3 zones of the adrenal cortex?

A
  • Zona Reticularis (inner): produces gondocorticoids (androgens)
  • Zona Fasciculata: produces glucocorticoids (cortisol) to control BGL
  • Zona Glomerulosa (outer): produces mineralocorticoids (aldosterone) to control sodium
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12
Q

What type of hormones are secreted by the adrenal cortex?

A

Steroid hormones

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13
Q

What causes the 3 zones of the cortex to be distinct from eachother?

A
  • Same cell types but different enzyme types present
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14
Q

What is the starting molecule for all steroid hormones?

A

Cholesterol

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15
Q

Describe androgen production.

A
  • Adrenal cortex is stimulated by ACTH from the anterior pituitary
  • Causes dehydroepiandosterone (DHEA) and (DHEA-S) production
  • These are precursors to testoserone, converted to testosterone in peripheral tissues
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16
Q

What are the effects of excessive adrenal androgens?

A
  • Masculinisation of women
  • Breast shrinkage, acne, irregular periods, facial hair
  • Plays a role in PCOS
  • Caused by ACTH overproduction
  • Treated with cyproterone acetate to block andorgen receptors
17
Q

Describe the effects of testosterone in men and women.

A

Men:

  • No identifiable function of adrenal andorgens as the testes already produce significant amounts of testosterone
  • Possible link with aggression in young boys

Women:

  • Kick starts puberty
  • Responsible for pubic hair growth and sex drive
18
Q

How is aldosterone produced?

A
  • A mineralocorticoid
  • Secretion is regulated by plasma levels of sodium and potassium via the renin-angiotensin system (RAAS)
  • Renin secreted when sodium in distal tubule is low
  • Renin converts angiotensinogen to angiotensin I
  • ACE (angiotensin converting enzyme) converts angiotensin I to angiotensin II
  • Angiotensin II stimulates aldosterone secretion in the adrenal cortex
19
Q

What is the function of aldosterone?

A
  • Conserves sodium when sodium is low and plasma potassium is high
  • Retains/increases blood volume
20
Q

What is cortisol?

A

A glucocorticoid, production stimulated by stress.

21
Q

When are cortisol levels highest?

A

At the start of the day, lowest at night.

22
Q

What are the metabolic actions of cortisol?

A

Metabolic effects:

  • Increases skeletal muscle catabolism, converts AAs to glucose
  • Increases lipolysis for energy source
  • Stimulates appetite

Cortisol causes fat stores and excess circulating fat to be relocated and deposited deep in the face and abdomen.

23
Q

What are the other functions of cortisol (non-metabolic)?

A
  • Anti-inflammatory actions
  • Immunosuppressive actions
  • Increases BGL
  • Can contirbute to emotional instability
24
Q

How is cortisol produced?

A
  • Hypothalamus releases corticotrophin releasing hormone (CRH) to the anterior pituitary
  • Anterior pituitary releases adrenocorticotrophic hormone (ACTH) to the adrenal cortex
  • Adrenal cortex secretes cortisol
25
Q

Give 3 examples of adrenal cortex hyperfunction.

A
  • Cushing’s syndrome
  • Conn’s disease
  • PCOS
26
Q

What is Cushing’s syndrome?

A
  • Excess cortisol
  • Can be caused by taking steroid hormones, or an adrenal or pituitary tumour
  • Muscle wastage, hypertension, hyperglycaemia, fat redistributed to face and abdomen
27
Q

What is Conn’s disease?

A
  • Rare
  • Excess mineral corticoids
  • Excess aldosterone
  • Retention of sodium, loss of potassium
  • Causes hypertension due to increased plasma volume
28
Q

What is PCOS?

A
  • Overproduction of adrenal androgens

- Facial hair in women

29
Q

Give an example of adrenal cortex hypofunction.

A

Addison’s disease:

  • Rare
  • Excess ACTH
  • Low cortisol, androgens and mineralocorticoids
  • Damage to adrenal or pituitary glands
  • Pigmentation of mucosal membranes (e.g. gingivae)
  • Progressive weakness, weight loss, lassitude
30
Q

Why are steroid hormones important in dentistry?

A
  • If a patient is on long-term systemic steroid medication they should recieve supplementary glucocorticoids when undergoing stressful treatement (i.e. dental procedures)
  • Treat patients on steroids earlier in the day when cortisol is highest

BDS 2: Foundation Basic Sciences (18 decks)

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