Brain Structure and Function

Brain Structure

• The brain is composed of three main parts: hindbrain, midbrain, and forebrain
• The hindbrain is located at the rear base of the skull and is involved in basic life processes
• The hindbrain includes the cerebellum, medulla, and pons
• The cerebellum helps control posture, balance, and voluntary movements
• The medulla controls breathing, heart rate, and various reflexes
• The pons functions as a bridge between the spinal cord and brain and produces chemicals for sleep

Midbrain

• The midbrain is a small part of the brain above the pons that integrates sensory information
• The medulla, pons, and midbrain compose most of the brain stem
• The reticular activating system (RAS) spans across these structures, alerting the brain to incoming signals and involved in the sleep/wake cycle

Forebrain

• The forebrain covers the brain's central core and includes the thalamus, which integrates sensory input
• The thalamus is a relay station for sensory information to the cortex
• All sensory information except smell enters the thalamus and is sent to the appropriate areas in the cortex
• The hypothalamus controls functions such as hunger, thirst, and sexual behavior, as well as body temperature reactions

Higher Thinking Processes

• The cerebral cortex and cerebrum surround the hindbrain and brain stem
• The cerebral cortex gives the ability to learn, store complex information, and project thinking into the future
• The cortex is the site of conscious thinking processes and is less than one-fourth inch thick

Limbic System

• The limbic system is composed of structures that regulate emotions and motivations
• The limbic system includes the hypothalamus, amygdala, thalamus, and hippocampus
• The amygdala controls violent emotions such as rage and fear
• The hippocampus is important for forming new memories

Brain Lobes

• The cerebrum is divided into two hemispheres, connected by the corpus callosum
• Each hemisphere has deep grooves marking regions or lobes
• The occipital lobe processes visual signals, and damage can cause visual problems
• The parietal lobe is concerned with sensory information from the body
• The temporal lobe is concerned with hearing, memory, emotion, and speaking
• The frontal lobe is concerned with organization, planning, and creative thinking