Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Clinical Biochem > Adrenal Gland Disorders > Flashcards

Adrenal Gland Disorders Flashcards

1
Q

Describe the structure of the adrenal gland

A
  • zona glomerulosa (outer cortex)
  • zona fasciculata (middle cortex)
  • zona reticularis (inner cortex)
  • adrenal medulla (centre of gland)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What hormone is produced by the zona glomerulosa ?

A

mineralocorticoid (aldosterone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the structure of the Zona glomerulosa ?

A
  • cells arranged in clumps
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the structure of the Zona fasciculata ?

A

cells arranged in cords alongside the blood sinusoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the structure of the Zona reticularis ?

A

network of smaller cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the structure of the adrenal medulla ?

A

loose network of neurosecretory cells surrounded by blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Function of the adrenal cortex

A

secretes 3 classes of steroid hormones
- glucocorticoids
- mineralocorticoids
- androgens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

function of the adrenal medulla

A
  • part of the sympathetic nervous system
  • produces catecholamines (adrenaline and noradrenaline
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What makes us the adrenal cortex ?

A
  • Zona glomerulosa
  • zona fasciculata
  • zona reticularis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What hormone is produced by the zona fasciculata ?

A

glucocorticoid (cortisol)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What hormone is produced by the zona reticularis ?

A

glucocorticoids & androgens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are external stimuli that affect the control of glucocorticoid secretion

A
  • hypoxia
  • hypoglycaemia
  • stress
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What internal stimuli is involved in the control of glucocorticoid secretion ?

A

diurnal rhythms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define Diurnal Rhythms

A
  • 24 hr cycle of physiological events that are synchronised with environmental cues such as the light-dark cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is the secretion of glucocorticoid stimulated ?

A
  • stimuli affects the hypothalamus
  • hypothalamus releases corticotrophin-releasing hormone
  • CRH acts on the pituitary gland
  • pituitary releases ACTH
  • ACTH acts on the adrenal cortex & triggers the release of glucocorticoids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What effect does cortisol have on the immune system ?

A

immune suppression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What effect does cortisol have on the liver ?

A

gluco-neogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What effect does cortisol have on muscle ?

A

protein catabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is another name for primary adrenal cortical hypofunction ?

A

Addison’s disease –> acute adrenal insufficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What effect does cortisol have on adipose tissue ?

A

lipolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are some clinical features of Addison’s disease ?

A

lethargy, weakness, weight loss, anorexia, hypotension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What causes Addison’s disease?

A
  • 90% of cases are autoimmune
  • remaining 10% can result from ; TB, tumour metastasis, amyloidosis, post adrenalectomy
  • withdrawal of glucocorticoids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the name of adrenal cortex hyper function the results in excess cortisol?

A

Cushing’s syndrome

20
Q

What is the name of adrenal hyperfunciton with results in excess mineralocorticoid ?

A

Conn’s Syndrome

21
Q

What causes Conn’s Syndrome?

A
  • adrenal adenoma = 75%
  • bilateral hyperplasia of zona glomerulosa
  • adrenal carcinoma
22
Q

What are some clinical features of Conn’s syndrome?

A

hypertension, muscle weakness, tetany, paresthesia

23
Q

Define tetany

A

muscle spasms

24
Q

Define Paresthesia

A

abnormal sensation –> tingling or prickling

25
Q

What are some clinical features of Cushing’s syndrome ?

A
  • moon face
  • proximal muscle wasting
  • purple striae
  • slow healing wounds
25
Q

What can cause Cushing’s disease?

A
  • antieror pituitary tumour creating excess ATCH –> Excess glucocorticoid released
  • Adrenal carcinoma or adenoma
  • ectopic ACTH - usually produced by a tumour located elsewhere
  • iatrogenic cushings = too much glucocorticoids being taken (medication)
26
Q

What are Catecholamines?

A

adrenaline and noradrenaline

27
Q

What do catecholamines influence ?

A
  • BP
  • cardiac output
  • fuel metabolism
  • sweating
  • pupil size
28
Q

What are the metabolic effects of adrenaline?

A
  • increase glycogen breakdown
  • gluconeogenesis
  • lipolysis
  • increase release of amino acids, lactate & pyruvate
29
Q

What is Pheochromocytoma ?

A
  • adrenal medulla hyperfunction
  • catecholamine secreting tumour
30
Q

What are some clinical features of pheochromocytoma ?

A
  • hypertension
  • vasomotor signs
31
Q

What are vasomotor signs ?

A

anxiety, sweating, palpitations, tremors and abdominal pain

32
Q

How is Cushing’s syndrome Diagnosed ?

A
  1. screening tests
  2. establish cause
33
Q

What are the 3 screening tests for Cushing’s?

A
  • 24h urine free cortisol
  • overnight dexamethasone suppression test
  • 48h low dose dexamethasone suppression test
34
Q

Describe the overnight dexamethasone suppression test

A
  • 1mg of Dexamethasone @ 11pm
  • 9am cortisol –> normal response = <50nmol/L
  • failure of suppression - Cushing’s syndrome (also pseudocushings & stress?)
35
Q

What is dexamethasone ?

A
  • a synthetic glucocorticoid
36
Q

What is the function of Dexamethasone ?

A
  • suppresses pituitary ACTH
  • dexamethasone leads to suppression of cortisol
37
Q

Describe the 48hr low dose dexamethasone suppression test

A
  • 0.5 mg dexamethasone every 6hrs for 2 days
  • 9am cortisol day 2
  • normal response - <50nmol/L
  • fewer false positives than overnight test
38
Q

What are the functions of Glucocorticoids?

A
  • increase hepatic glujconeogeneis & hepatic glycogen storage
  • increase breakdown of plasma & muscle protein to AA’s
  • increase release of glycerol & FFA’s from adipose tissue
  • anti-inflammatory
39
Q

Describe how you can measure Cortisol

A
  • diurnal variation - levels high in morning & low/undetectable at night
  • part of stress response
  • some anti-inflammatory drugs may interfere in measurement
40
Q

How do you measure Aldosterone ?

A
  • measure after patient has been supine overnight & then upright
  • varies greatly with posture
  • usual to measure with renin
41
Q

What are some biochemical signs of Adrenal Hypofunction?

A
  • hyponatraemia
  • hyperkalaemia
  • hyperuricaemia
  • hypoglycaemia
42
Q

What’s the diagnostic approach for adrenal hypofucntion ?

A
  • 9am cortisol
  • usually have to perform short synacthen test
  • then you need to establish primary or secondary - measure ACTH
  • ACTH High = primary
  • ACTH Low = secondary
43
Q

Describe a Synacthen test

A
  • measure baseline cortisol
  • give synacthen
  • measure cortisol
  • cortisol should increase to a value >550 nmol/L
44
Q

What are some biochemical signs of Conn’s Syndrome?

A
  • hypokalaemia
  • urinary potassium innaproriately high
  • high aldosterone & low renin
45
Q

Describe Congenital Adrenal Hyperplasia

A
  • inherited metabolic disorder of adrenal hormone secretion
  • autosomal recessive
  • 21-hydroxylase deficiency - can be partial or incomplete
  • 21-hydorxylase deficiency = increase in 17-hydroxyprogesterone
46
Q

What are some clinical signs of classical Congential Adrenal Hyperplasia ?

A

Lack of cortisol & aldosterone
–> adrenal crisis
-dehydration
-shock
-death

47
Q

Describe Non-Classical CAH

A
  • milder non-life threatening
  • partial enzyme deficiency
  • low cortisol, normal aldosterone & androgens
  • premature pubic hair, menstrual irregularities, acne & fertility problems later
48
Q

Describe diagnostic testing for CAH

A
  • Hormone measurement - 17-OHP
  • clinical evaluation
49
Q

What are some treatments for CAH ?

A
  • glucocorticosteroid
  • mineralocorticoid (classical form)
50
Q

What is a possible treatment for a Pheochromocytoma ?

A
  • surgical resection
  • beta-blocker to control BP

Clinical Biochem (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions