Neuroendocrinology (recap) Flashcards

1
Q

Describe how the nervous system works

A

Nervous system uses neurotransmitters to relay messages from one nerve to another or from a nerve to a tissue

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2
Q

Describe how the endocrine system works

A

Endocrine system releases hormones into blood to circulate to
tissues

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3
Q

What do endocrine glands do?

A

Release hormones directly into the blood (ductless)

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4
Q

What is the effect of hormones on a tissue determined by?

A

The effect of a hormone on a tissue is determined by the plasma concentration and the number of active receptors

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5
Q

What is plasma hormone concentration determined by?

A
  1. Rate of secretion of hormone from endocrine gland
  2. Rate of metabolism or excretion of hormone
  3. Quantity of transport proteins
  4. Changes in plasma volume
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6
Q

What does the magnitude of hormone effect depend on?

A
  1. Concentration of the hormone
  2. Number of target receptors on the cell
  3. Affinity of the receptor for the hormone
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7
Q

What is ‘downregulation’?

A

Decrease in receptor number in response to high concentration of hormone (e.g., age & -receptors).

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8
Q

What is ‘upregulation’?

A

Increase in receptor number in response to low
concentration of hormone

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9
Q

What are the mechanisms of hormone action?

A
  1. Activation of genes to alter protein synthesis.
    * Steroid hormones.
  2. Activating ‘second messengers’ in the cell via G protein.
  3. Altering membrane transport.
    * Insulin via tyrosine kinase.
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10
Q

What are the ‘second messengers’ in the cell?

A
  • Cyclic AMP.
  • Ca2+.
  • Inositol triphosphate.
  • Diacylglycerol.
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11
Q

What is the relationship between the hypothalamus and the pituitary gland?

A

Hypothalamus controls secretions from pituitary gland

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12
Q

Where is ADH secreted from and what does it do?

A
  • Secreted from the posterior pituitary gland.
  • Reduces water loss from the body to maintain plasma volume.
  • Favours reabsorption of water from kidney tubules to capillaries.
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13
Q

What is ADH release stimulated by?

A

1) high plasma osmolality
2) low plasma volume
* Due to sweat loss without water replacement

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14
Q

How does ADH concentration change during exercise?

A

Increases during
exercise >60% VO2
max to maintain plasma
volume.

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15
Q

Where is aldosterone secreted from and what does it do?

A
  • Secreted from the adrenal cortex
  • Control of Na+ reabsorption and K+ secretion
  • Na+/H2O balance
  • Regulation of blood volume and blood pressure
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16
Q

What stimulates aldosterone release?

A
  • Increased plasma K+ concentration (negative feedback loop)
  • Decreased plasma volume
17
Q

Describe the renin-angiotensin-aldosterone system.

A

Decrease in plasma volume leads to decreased BP at the kidney, or an increase in sympathetic nerve activity. This causes renin to be released leading to angiotensin I (ACE converts to angiotensin II) which triggers aldosterone release increasing Na+ reabsorption.

18
Q
A