Question

the reason of brain portion that contains hunger pangs is

Answer 1

Hunger, thirst, body temprature, water balance, blood pressure etc. are some of the biological functions handled by Hypothalamus, which is situated in forebrain and is a part of the Limbic system of our body. It is almost the size of an almond. The hormones secreted by these glands regulate neurotransmitters like epinephrine and serotonin(which gives us feeling of fullness or satiety after eating) . Neurotransmitters like these are communication variables of our nervous system.

Answer 2

The part of brain which controls hunger, thirst, sleep and temperature is controlled by hypothalamus