Adrenaline is a hormone secreted by adrenal medulla during stress. This is called as emergency hormone because it initiates quick reation which makes the individual to think and respond quickly to the stress. The hormone increases metabolic rate. there occurs dialation of blood vessels going to heart and the brain. The blood vessels reaching skin and kidneys constrict inorder to provide more blood to the heart and the brain. they also increase fat metabolism thereby synthesising more energy.
This substage involves coordinating sensation and new schemas. For example, a child may suck his or her thumb by accident and then later intentionally repeat the action. These actions are repeated because the infant finds them pleasurable
