Stress Response: General Adaptation Syndrome, Cortisol and Appraisal

Stress is the response to a perceived demand. The MCAT tests Selye's three stages, the two body systems that carry the response, and Lazarus's idea that appraisal decides how stressful an event is.

General adaptation syndrome

Two pathways

The hypothalamus releases CRH, the anterior pituitary releases ACTH, and the adrenal cortex releases cortisol. Cortisol exerts negative feedback on the hypothalamus and pituitary. Chronic high cortisol impairs immunity and memory, partly through effects on the hippocampus.

Appraisal

Lazarus's model says stress depends on how an event is judged. In primary appraisal you judge whether the event is irrelevant, positive or threatening. In secondary appraisal you judge whether you have the resources to cope. Eustress is positive stress, such as a promotion, and distress is negative stress.

Common traps

• Placing cortisol in the SAM system. It belongs to the HPA axis.
• Saying the adrenal medulla makes cortisol. The cortex does.
• Calling exhaustion the first stage. Alarm comes first.
• Reversing the appraisals. Primary is the threat, secondary is the coping resources.

One-minute recap

Alarm, resistance, exhaustion. SAM is fast and uses epinephrine. HPA is slower and uses cortisol with negative feedback. Appraisal decides how stressful an event is.