The Fight or Flight Response

Question 1

Outline the fight or flight response

Answer 1

The way in which an animal responds when stressed. The body becomes physiologically aroused in readiness to fight an aggressor or in some cases flee.

Question 2

Describe the role of the amygdala and hypothalamus in the fight or flight response

Answer 2

• When faced with a threat, the amygdala is mobilised. The amygdala associates sensory signals with emotions associated with fight or flight (fear/anger)
• The amygdala sends a distress signals to the hypothalamus, which communicates to the rest of the body through the sympathetic nervous system.

Question 3

How does the body’s state changed when stressed?

Answer 3

When a stressor is perceived, the first thing that happens is the ANS changes from its normal resting state (parasympathetic state) to the physiologically aroused (sympathetic state)

Question 4

What are the 2 main systems in the stress response?

Answer 4

• The sympathetic nervous system
• The hypothalamic-pituitary adrenal axis

Question 5

Outline the sympathetic nervous system as a stress response

Answer 5

• Response to acute (sudden) stressors
• When the SNS is triggered, it behind the process of preparing the body for the rapid action for fight or flight.
• SNS sends a signal to the adrenal medulla, responds by releasing adrenaline and noradrenaline into the bloodstream
• Fight or flight response is produced

Question 6

Describe adrenaline as a part of the response to acute stressors

Answer 6

• Adrenaline circulates through the body, causes physiological changes. Heart beats faster, pushing blood to muscles, heart and other vital organs, and blood pressure increases. Breathing becomes more rapid to take in as much oxygen as possible.
• Adrenaline also triggers release of glucose and fats, supplying energy to parts of the body associated with the fight or flight response

Question 7

What happens after the acute stressor passes?

Answer 7

The parasympathetic branch dampens down the stress responses

Question 8

Outline the hypothalamic-pituitary adrenal axis as a stress response (HPA axis)

Answer 8

• Response to chronic (ongoing) stressors
• If brain continues to perceive something as threatening, the second system kicks in.
• As adrenaline subsides, the hypothalamus actives a stress response system (HPA axis)
• HPA axis relies on a series of hormonal signals to keep SNS working.

Question 9

Describe the hypothalamus as a part of the response to chronic stressors (1)

Answer 9

In response to the continues threat, the hypothalamus releases a chemical messenger, CRH, which is releases into the bloodstream.

Question 10

Describe the pituitary gland as a part of the response to chronic stressors (2)

Answer 10

• On arrival at the pituitary gland, CRH causes the pituitary to produce and release ACTH.
• From the pituitary, ACTH is transported in the bloodstream to its target site in the adrenal glands

Question 11

Describe the adrenal gland as a part of the response to chronic stressors (3)

Answer 11

• ACTH stimulates the adrenal cortex to release various stress-related hormones (glucose and cortisol).
• Cortisol is responsible for effects in the body that are important in the fight or flight response. Either positive (burst of energy and lower sensitivity to pain) or negative (impaired cognitive performance and a lowered immune response)