1. 6.2 The Brain (cont.) Human brain weighs 1,350 grams (3 pounds)
Has consistency of Jell-O

2. Major Parts of the Brain
1. Forebrain
Largest part of the brain
Refers to the right and left hemispheres
Responsible for infinite number of functions
Covered by a thin layer of cells called the CORTEX (which is then divided into the 4 lobes of the brain

3. Limbic System
Includes ½ dozen interconnected structures that make up the core of the forebrain
Involved in motivational behaviors such as obtaining food, sex; emotions like fear, anger, aggression; storing of memories

4. Limbic System
Hypothalamus: hunger, thirst, sex, fight or flight, hormone secretion
Thalamus: receives sensory info, processes then relays info to cortexes
Amygdala: forms, recognizing, and remembering emotional experiences and facial expressions
Hippocampus: saves many kinds of fleeting memories

5. Major Parts of the Brain
2. Midbrain
Centered underneath the two hemispheres of the Forebrain
Involved in visual and auditory reflexes
Reticular formation (RF) extends from Midbrain to spinal cord, and it alerts/arouses the forebrain for incoming info from the senses

6. Major Parts of the Brain
3. Hindbrain: Its structures and functions are in the most primitive of brains and have remained unchanged over evolutionary time

7. 3. Hindbrain: structures
Pons: bridge between spinal cord and brain; makes sleep chemicals
Medulla: at top of spinal cord; controls vital reflexes---heart rate, breathing, etc
Cerebellum: at very back and underneath the brain; coordinates movements, timed motor responses