The big pink part of the brain is the medulla oblongata. Which regulates our unconscious functions.

The blue part is the RAS: reticular activating system. It activates the brain in danger situations and helps to regulate sleep and attention.

The yellow part is the Thalamus. It's sensory information and it regulates emotional aspects of behavior.

The little pink part of is the hypothalamus. It's the endocrine system. It regulates hunger,thirst,temperature control and sexual behavior