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Metabolic - Endocrinology > Y2 Endocrinology Revision > Flashcards

Y2 Endocrinology Revision Flashcards

1
Q

What are the subtypes of CD4+ cells?

A

Effector subsets: fight pathogens

  • Th1: IFN-gamma
  • Th2: IL-4 & IL-5
  • Th17: IL-17

Regulatory subsets: regulate the effectors

  • Tr1: IL-10
  • Th3: TGF-beta
  • CD25: IL-10 & TGF-beta
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2
Q

What are Th1 cells responsible for?

A
  • Fight intracellular pathogens, release IFN-gamma
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3
Q

What are Th2 cells responsible for?

A

Fight extracellular pathogens, secrete IL-4&5

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4
Q

What are Th17 cells responsible for?

A

Fighting extracellular bacteria and fungi, secrete IL-17

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5
Q

What are microfold (M) cells?

A
  • Specialised antigen uptake cells found in mucosa
  • Take up antigens by phagocytosis
  • M cells release antigens which are picked up by APCs which activate T-cells in GALT
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6
Q

What is the dominant antibody class in the mucosal immune system?

A

IgA

  • IgA is dimeric
  • sits on the luminal surface where is neutralizes pathogens
  • we produce 5g of IgA everyday
  • binds to receptor via J chain and transports across the cell, it uses J chain to stop getting washed away
  • coats membrane and stops pathogens binding
  • IgA doesn’t produce inflammation or activate compliment
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7
Q

What can take over if IgA is not present?

A

IgM – pentameric, also has a J chain

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8
Q

What is NOD2?

A
  • Protein encoded by the NOD2 gene on chromosome 16
  • recognises bacterial molecules and stimulates an immune reaction
  • expressed in Paneth cells, leads to expression of anti-microbial peptides
  • mutation in NOD2 linked to Crohn’s
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9
Q

What are aminosalicylates?

A

Drugs that dampen inflammation, mech. not well understood

  • Mesalamine is the active ingredient

examples:

  • Sulfasalazine
  • Mesalazine
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10
Q

What is methotrexate?

A

Immunosuppressor

  • inhibits DNA synthesis and cellular replication
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11
Q

What is infliximab?

A

MAB – binds to TNF-alpha and stops it working

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12
Q

Discuss gastroenteritis

A

Infectious diarrheoa, inflammation of gut
- antibiotics not recommended

usually viral:

  • norovirus
  • rotavirus

bacteria:

  • campylobacter
  • E.coli
  • salmonella

parasites:
- giardia lambila

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13
Q

What is the role of the appendix

A

GALT – storage area of flora

people without an appendix often get recurrent bouts of c.diff because they don’t have their flora In storage

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14
Q

What is absorbed in the duodenum?

A

Iron

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15
Q

What do goblet cells secrete?

A

Mucins

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16
Q

What is absorbed in the jejunum?

A

Sugars
Amino acids
Fatty acids

17
Q

What is absorbed in the ileum?

A

B12

Bile salts

18
Q

What are the 4 zones of the adrenal glands?

A
  1. Glomerulosa: Mineralocorticoids
  2. Fasciculata: Glucocorticoids
  3. Reticulans: Androgens
  4. Medulla: Catecholamines (80% adrenaline, 20% noradrenaline)
19
Q

What are steroid hormones derived from?

A

Cholesterol

20
Q

Discuss the HPA axis

A
  1. Hypothalamus (corticotropin releasing H)
  2. Pituitary (adrenocorticotropic H)
  3. Adrenal glands (cortisol)
21
Q

Where is aldosterone released from?

A

Adrenal glands

22
Q

Discuss adrenal insufficiency

A

Primary: problem with gland not releasing cortisol

Secondary: problem with anterior pituitary not releasing ACTH

Tertiary: hypothalamus not releasing CRH

23
Q

Discuss Addison’s disease

A
  • Primary adrenal insufficiency
  • Usually autoimmune
  • Diagnosed when cortisol <100mmol/L
  • check cortisol, inject ACTH and check again
24
Q

What is fludrocortisone?

A

Synthetic adrenocortical steroid – mineralocorticoid and glucocorticoid properties

1) Increases ion and water transport
2) Raises extracellular fluid volume and blood pressure
3) Lowers potassium levels.

25
Q

What are the consequences of prolonged steroid use?

A

Adrenal atrophy, lack of ACTH production

26
Q

Discuss Cushing’s syndrome

A
  • Prolonged exposure to elevated levels of glucocorticoids
  • most common cause is use of exogenous steroids e.g. for COPD

*test for urine cortisol – has to be 2x normal

27
Q

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

A

Syndrome = symptoms associated with hypercortisolism

Disease = ACTH producing adenoma in pituitary

28
Q

What is the dexamethasone suppression test?

A

Dexamethasone = synthetic cortisol

Given to patient, should cause cortisol levels to drop below 50nmol/L

*If not – Cushing’s

29
Q

What is the function of mineralocorticoids?

A

Salt and water balance

30
Q

What is a glucocorticoid?

A

*Cortisol is a glucocorticoid

Corticosteroids involved in the metabolism of carbs, proteins, fats

Have anti inflammatory properties e.g. hydrocortisone

31
Q

What is intrinsic clearance?

A

Theoretical max clearance of unbound drug by an eliminating organ

32
Q

What are the consequences of a lack of mineralocorticoids?

A

Fatal shock due to diminished cardiac output

33
Q

What converts corticosterone to aldosterone?

A

18-hydroxylase

34
Q

What are the actions of cortisol?

A
  • Increases gluconeogenesis
  • Induces glucagon activity to increase blood sugar
  • increases protein catabolism
35
Q

What is congenital adrenal hyperplasia?

A
  • Most commonly due to 21-Hydroxylase deficiency
  • Results in decreased cortisol and aldosterone
  • Excessive androgen production leading to masculinisation of female genitals

Other cause = 11B-Hydroxylase deficiency which causes increased androgens and increased mineralocorticoids

36
Q

What is the role of angiotensin II in the production of mineralocorticoids?

A

Converts cholesterol to pregnenolone

Converts corticosterone to aldosterone

38
Q

Which drugs have high glucocorticoid activity?

A

Dexamethasone

Betamethasone

39
Q

Which drugs have moderate glucocortioid activity?

A

Hydrocortisone, Triamcinolone, Prednisolone

40
Q

What is fludrocortisone?

A

Synthetic adrenocortical steroid possessing very potent mineralocorticoid properties and high glucocorticoid activity

Metabolic - Endocrinology (12 decks)

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