The fight or flight response including the role of adrenaline.

The idea

Faced with a threat, the amygdala signals the hypothalamus, activating the sympathetic branch of the autonomic nervous system. This stimulates the adrenal medulla to release adrenaline into the bloodstream, causing rapid physiological changes. Heart rate rises, breathing quickens, pupils dilate, and stored glycogen converts to glucose for muscle energy. Digestion is suppressed as it is not needed for immediate survival. Once the threat passes, the parasympathetic branch returns the body to baseline. For evaluation, Taylor et al. (2000) argued the model is beta biased as females often show a tend and befriend response, while Gray (1988) noted the initial reaction is usually to freeze and scan for information.

What earns the marks

• Amygdala appraises the threat and sends a distress signal to the hypothalamus.
• Hypothalamus activates the sympathetic branch of the autonomic nervous system (the sympathomedullary pathway).
• Adrenal medulla releases adrenaline directly into the bloodstream, which is why the response is almost immediate.
• At least three physiological effects with a survival reason: raised heart rate to deliver oxygen, glycogen to glucose for energy, dilated pupils, suppressed digestion.
• Parasympathetic branch restores resting state once the threat ends.
• Evaluation: Taylor et al. (2000) on tend and befriend and beta bias; Gray (1988) on the freeze response; chronic activation linked to raised blood pressure and heart disease in modern life.

Common mistakes and how to put them right

• Confusing adrenaline with cortisol.

  Put it right: Adrenaline comes from the adrenal medulla in the acute response; cortisol comes from the adrenal cortex during prolonged stress.

• Describing the effects without saying why they help, when the adaptive reason is usually required for full explanation.

• Forgetting the parasympathetic 'rest and digest' return, so the answer implies arousal simply stops on its own.

• Writing the evaluation as 'it ignores women' instead of naming tend and befriend and identifying beta bias as the criticism.

Exam tips

• Learn the pathway as a chain of four links (amygdala, hypothalamus, sympathetic branch, adrenal medulla) so an outline writes itself.
• Pair each physical change with its function; a list of changes reads as description while a change plus purpose reads as explanation.
• In extended response questions, evaluation carries significant weight, so ensure concepts like tend and befriend, the freeze response, and the costs of chronic arousal are developed in depth rather than just listed.