Th Stress Response Flashcards Preview

ESA 1 - Body Logistics > Th Stress Response > Flashcards

Flashcards in Th Stress Response Deck (9)
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1
Q

What is stress?

A

A state of real or perceived threat to homeostasis.

2
Q

What is the stress response?

A

Maintenance of homeostasis in the presence of averse stimuli (stressors), requiring activation of:

  • endocrine system
  • nervous system
  • immune system
3
Q

What are the effects of the stress response?

A

Activation of the stress response initiates behavioural and physiological changes that improve an individual’s chance of survival when faced with homeostatic challenges.

Behavioural effects inc.:

  • increased awareness
  • improved cognition
  • euphoria
  • enhanced analgesia

Physiological adaptations inc.:

  • increased cardiovascular tone, respiratory rate and intermediate metabolism
  • inhibition of general vegetative functions such as feeding, digestion, growth, reproduction and immunity
4
Q

Where are the principal effectors of the stress response localised?

A

Hypothalamus
Anterior pituitary
Adrenal gland

5
Q

What are the effects of hormones released by the adrenal gland in the stress response?

A
  • Cortical hormones:
    Glucocorticoids (cortisol)
    Mineralocorticoids (aldosterone)
  • Effects:
    Increase BP
    Release glucose into bloodstream
    Inhibit non-emergency services
6
Q

Describe the hypothalamo-pituitary-adrenal axis.

A
  1. Hypothalamus releases CRH (corticotropin releasing hormone).
  2. CRH stimulates ACTH (adrenocorticotropic hormone) release from the AP.
  3. ACTH stimulates cortisol release from the adrenal cortex.
  4. Cortisol stimulates response from systemic effectors and inhibits ACTH and CRH release - negative feedback loop.
7
Q

What is special about the adrenal medulla?

A

Contains neurocrine Chromaffin cells (innervated by preganglionic sympathetic neurons). Release adrenaline and noradrenaline into the bloodstream.

8
Q

Which hormones mediate the short term stress response?

A

Adrenaline & noradrenaline:

  1. Glycogen breakdown to glucose - increased blood glucose
  2. Increased BP and heart rate
  3. Increased respiratory rate
  4. Increased metabolic rate
  5. Change in blood flow patterns leading to increased alterness and decreased digestive, excretory and reproductive system activity.
9
Q

Which hormones mediate the long term stress response?

A

HPA axis-mediated release of:

  • mineralicorticoids:
    1. Sodium and water retention by kidneys
    2. Increased blood volume and BP
  • glucocorticoids:
    1. Proteins and fats converted to glucose or broken down for energy
    2. Increased blood sugar
    3. Suppression of immune system