Biology of Stress Flashcards Preview

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Flashcards in Biology of Stress Deck (12)
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1
Q

Definition of stress

A

A biological response to +ve/-ve triggers which leads to SNS and hypothalamic pituitary adrenal axis activation

2
Q

What is stress
What are the 2 most potent stressors
What 2 systems does it activate

A

P+ve/-ve triggers => physiological mechanism

Potent stressors

  • emotions (joy, anger, fear)
  • expectations

Activates SNS and hypothalamic pituitary adrenal (HPA) axis

3
Q

What 5 brain areas are involved in HPA

A
Amygdala
Hypothalamus
Pituitary gland
Prefrontal cortex
Hippocampus
4
Q

What is the function of the amygdala

How many can be found in the brain

A

Receives threat and danger info and conveys emotional info => other brain regions via corticotrophin releasing factor

1 found in each side

5
Q

What is the function of the hypothalamus and pituitary

A

Helps control emotional reactions, feeding, drinking

Emotional responses organised here trigger hormonal secretion in the pituitary

6
Q

What is the function of the hippocampus

How many can be found in the brain

A

Organises memory storage and memory retrieval in cortex

1 found in each side

7
Q

What is the function of the prefrontal cortex

A

Frontal most region of frontal cortex

Planning and organisation of behaviour based on use of working memory

8
Q

What is the function of the adrenal glands

What do they release and where from

A

ACTH released by pituitary acts on adrenal glands

Cortisol released from zona fasciculata into the blood

9
Q

Where are the cortisol binding sites found

A

Glucocorticoid receptors on

  • hypothalamus
  • hippocampus
  • pituitary
  • pre frontal cortex
10
Q

Describe the pathway in the HPA

What type of feedback loop is this

A

Amygdala receives threatening stimuli => CRF onto hypothalamus

Hypothalamus involved in emotional reaction => CRF onto pituitary

Pituitary => ACTH into bloodstream

Adrenal cortex => cortisol into bloodstream

Cortisol acts on glucocorticoid receptors and stimulates

  • prefrontal cortex
  • hippocampus

Cortisol acts on glucocorticoid receptors and inhibits

  • pituitary
  • hypothalamus

Hippocampus and prefrontal cortex fire AP on and inhibit hypothalamus

NEGATIVE FEEDBACK

11
Q

Compare the normal HPA function vs abnormal function in chronic stress

A

Baseline levels of cortisol always secreted but broken down by bloodstream enzymes

Constant barrage of glucocorticoids => death of receptors and cells
–ve feedback system fails => +ve feedback

12
Q

Describe the fight or flight response invovled in the stress response

A

Hypothalamus stimulates SNS

Adrenal medulla releases adrenaline
Peripheral SNS releases NA

Both lead to

  • increased HR, BP
  • iris contracts => larger pupil
  • decreased gut motility

PNS calms body down

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