II. How the Nervous System Works

A. Definition Nervous system never rests (even when asleep) Controls body functions, emotions, movements, thinking & behavior All parts of nervous system are protected (skull protects brain; vertebrae protects spinal cord)

B. Parts of the Nervous System Central Nervous System (CNS)– includes brain & spinal cord Spinal cord: consists of nerves that run down back & transmits messages between body & brain Peripheral Nervous System (PNS)- includes smaller nerves that branch out from spinal cord Takes info from body’s organs to CNS & return info to organs

C. Parts of the PNS Somatic Nervous System (SNS): controls voluntary activities Autonomic Nervous System (ANS): controls involuntary activities Has two parts: Sympathetic Nervous System– prepares body for dealing with emergencies or strenuous activity Parasympathetic Nervous System– saves energy to help body recover from strenuous activity

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III. Parts of the Brain

A. The Hindbrain 1. Location- Rear base of the skull 2. Includes: Cerebellum- behind spinal cord Helps control posture, balance, and voluntary movements Medulla- controls breathing, heart rate, and a variety of reflexes Pons- functions as bridge between spinal cord & the brain Produces chemicals the body needs for sleep 7

B. The Midbrain 2. Includes: Location- Small part of the brain above pons (part of the brain stem) 2. Includes: Reticular Activating System (RAS) spans across these structures Alerts the rest of brain to incoming signals & is involved in sleep/wake cycle 8

C. The Forebrain Location- Covers brain’s central core Includes: Thalamus- Station for info traveling to & from Hypothalamus- Controls hunger, thirst, & sexual behavior 2. High thinking processes are also housed in forebrain Cerebral cortex- outer layer of forebrain Gives you the ability to learn & remember Cerebrum- inside layer of the forebrain 9

D. The Limbic System Location- Found in core of forebrain 2. Role- Controls emotions & motivations Includes hypothalamus; amygdala (controls violent emotions); thalamus; & hippocampus (important in the formation of memories) Covering all these parts is cerebrum 10

E. Cerebrum Consists of 2 hemispheres, or halves 2. The hemisphere is connected by a band of fibers called corpus callosum (carries messages between two) 3. Each hemisphere has deep grooves that mark regions known as lobes Occipital Lobe: Controls vision Parietal Lobe: Concerned with info from senses all over body Temporal Lobe: Concerned with hearing, memory, emotion, & speaking Frontal Lobe: Organization, planning, & creative thinking. Both hemispheres have same 4 lobes 11