BRAINCAKEThe Fight or Flight Response
When a mammal detects a threat, such as a predator, its body prepares either to fight or to run away. This is the fight or flight response. It is coordinated by the hypothalamus and involves both the nervous system and hormones.
1. Receptors detect the threat and impulses pass to the cerebrum, which recognises the danger and stimulates the hypothalamus.
2. The hypothalamus activates the sympathetic nervous system. Sympathetic neurones stimulate effectors directly, and also stimulate the adrenal medulla to release adrenaline into the blood.
3. The hypothalamus also releases corticotropin releasing factor (CRF) into the blood. This causes the anterior pituitary gland to release adrenocorticotropic hormone (ACTH), which stimulates the adrenal cortex to release corticosteroids such as cortisol.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
Key terms in this lesson
- adrenal medulla
- The inner part of the adrenal gland that secretes adrenaline and noradrenaline into the blood when stimulated by sympathetic neurones.
- pituitary gland
- An endocrine gland at the base of the brain, controlled by the hypothalamus, that secretes hormones controlling other endocrine glands and processes.
More in Hormonal Communication
- Insulin
- Glucagon
- Mechanism of Insulin Secretion
- Diabetes Mellitus
- Coordinating Nervous and Hormonal Responses
- Adrenaline and the Second Messenger Model
- The Cardiovascular Centre in the Medulla
- Control of Heart Rate
All 19 lessons in Hormonal Communication · All OCR A-level Biology topics