Lecture 1- Introduction To Endocrinology Flashcards

1
Q

Primary endocrine glands

A

Their main function is to secrete hormones e.g. pituitary, thyroid, adrenal glands and the pancreas

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2
Q

Secondary endocrine glands

A

Their main function is not to secrete hormones, but contain cells which to e.g. kidneys, stomach and liver

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3
Q

Exocrine glands

A

Secrete products into ducts that carry secretions unto body cavities, lumen of organ or to outer surface of body i.e. target organ

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4
Q

Endocrine hormone

A

Secrete hormones directly into the blood that act on distant cells

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5
Q

Paracrine hormone

A

Acts locally on neighbouring cells

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6
Q

Autocrine hormones

A

Acts on the same cell that secreted the hormone

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7
Q

Diurnal

A

Secreted daily

- cortisol is an example which is high in the morning and low at night

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8
Q

Melatonin

A

Secreted with a daily (circadian) rhythm

  • secretion peaks at night
  • controls sleep patterns
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9
Q

Positive feedback

A

Rate of process increased and product increases

E.g. oxytocin which stimulates and enhances labour contractions

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10
Q

Negative feedback

A

Rate of process decreased as the formation of the product increases

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11
Q

Acromegaly

A

Excess of growth hormone during adulthood
-symptoms include swollen hands/feet (squashed nerves = carpal tunnel syndrome); abnormal periods and erectile dysfunction; sleep apnoea

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12
Q

Down regulation

A

If a hormone is present in excess the number of target cells may decrease, decreasing sensitivity to hormone

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13
Q

Upregulation

A

If a hormone is deficient, the number of target cell receptors may increase, to increase sensitivity to hormone

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14
Q

Hypothyroidism

A

Low T3 and T4; high TSH

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15
Q

Hyperthyroidism

A

High T3 and T4; low TSH

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16
Q

Cushing’s syndrome

A
  • Overproduction of ACTH from pituitary

- Overproduction of cortisol from the adrenal glands

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17
Q

Addison’s disease

A

Lack of cortisol and aldosterone

  • due to autoimmune destruction of adrenal gland
  • symptoms include weight loss; dizzy spells; hyperpigmentation due to build up to ACTH which stimulates production of melanin by melanocytes); frequent urination due to lack of aldosterone (less sodium reuptaken in the kidneys)
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18
Q

Cholesterol

A

Precursor to steroid hormones

19
Q

Thyrotoxicosis

A

Excess thyroxine (T4) production

20
Q

Hypoglycaemia

A

Insulin excess, low blood sugar

21
Q

Insulin and cytokines act via which kind of receptor?

A

Intracellular (phosphorylation of intracellular proteins)

22
Q

Steroid, thyroid hormones and vitamin D act via which type of receptor?

A

Intracellular (nuclear receptors)

23
Q

Catecholamines, NO and peptide hormones act via which type of receptor?

A

Extracellular (g protein coupled receptors GPCRs)

24
Q

What is the main action of intracellular receptors for hormones?

A

Phosphorylation of intracellular proteins

25
Q

What is the main action of a GPCR leading to the specific hormone response?

A

Increase of intracellular cAMP

26
Q

What is the effect to of insulin on glucose uptake?

A

Increased into fat and muscle

27
Q

Hormone

A

A regulatory substance produced in an organism and transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action

28
Q

Catecholamines

A

Water soluble e.g. adrenaline/ noradrenalin/ melatonin

29
Q

Peptides

A

Water soluble e.g. insulin/ PTH

30
Q

Steroids

A

Lipid soluble e.g. cortisol/ sex steroids/ vitamin D

31
Q

Action of lipid soluble hormones

A
  1. Diffuses through the blood and plasma membrane into a cell
  2. Hormone binds to receptor in cystic or nucleus
  3. Alters gene expression
  4. Activates or suppresses the production of protein
32
Q

Action of water soluble proteins

A
  1. Diffuses through blood and binds to receptor on exterior plasma membrane of target cell
  2. Hormone receptor compels activates the membrane protein (G protein)
  3. Activated G protein activates adenylyl cyclise
  4. This converts ATP to cAMP in the cystol (Ca 2+ is another secondary messenger)
  5. cAMP activates protein kinases (phosphorylates target cellular proteins)
  6. Produces physiological response- activation/suppression
  7. Phosphodiesterase deactivates cAMP
  8. Works with low concentration of hormone as second messenger causes cascade effect
33
Q

Permissive effect

A

The response only occurs when there is a recent or simultaneous presence of a second hormone

34
Q

Synergistic effect

A

Effect of two hormones acting together is greater than the sum of their individual effects

35
Q

Antagonistic effect

A

When one hormone opposes the actions of another hormone

36
Q

Gigantism

A

Caused by an adenoma (tumour of the pituitary gland)

  • excessive growth hormone in children
  • symptoms include large hands/feet; prominent jaw and forehead; flat nose/larger head/lips
37
Q

What is insulin’s effect on glycogen?

A

Increase in glycogen synthesis

38
Q

What is insulin’s effect on triglycerides?

A

Increase storage in adipose tissue

39
Q

What is insulin’s effect on proteins?

A

Increased protein synthesis

40
Q

What is insulin’s effect on the liver?

A

Decreases hepatic gluconeogenesis

41
Q

What are the two main disorders associated with insulin deficiency?

A

Type I and type II diabetes

42
Q

Excess insulin causes what condition?

A

Hypoglycaemia

43
Q

Ghrelin

A

Increases food uptake

44
Q

Where is ghrelin produced?

A

Stomach