Adrenaline (Edexcel GCSE Biology): Revision Notes

Adrenaline

• Produced by adrenal gland which secrete this hormone which prepares body for action
• 'Fight/flight' response whether to fight back or run away by for example by an attack of an enemy- activates process that increases O2 and glucose supply to cells.

Increases breathing rate/deeper breaths	More O2 into body
Increases heart rate	Adrenaline binds specific receptors to the heart so heart pumps contracts more forcefully and faster More blood to muscles (more glucose and O2 for respiration)
Increases blood pressure	Causes vasodilation so more blood can be pumped around
Increases blood flow to muscles	Blood diverted away from intestine Makes us have 'butterflies' in stomach/go pale
Increases blood sugar levels by stimulating liver to change glycogen to glucose	In the liver stored carbohydrate is changed to glucose and released into blood which is absorbed by muscle cells for respiration.

When body detects stressful situation… Sends nervous impulses to adrenal glands which secretes adrenaline