Ch. 22 section 2 Divisions of the Nervous System CNS PNS brain spinal cord cerebrum cerebellum brainstem reflex concussion somatic nervous system autonomic nervous sytem

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Objectives: 1. Describe the structures and function of the central and peripheral nervous system. 2. Explain what a reflex is. 3. Identify two ways in which the nervous system can be injured.

nervous system has two divisions: central nervous system: brain and spinal cord peripheral nervous system: nerves located outside of the CNS

A. Central Nervous System  1. control center of the body   a. all info is brought to CNS   b. brain: controls most fxns of the body   c. spinalcord: thick column of nerve tissue -links brain to nerves in the PNS

B. The Brain  1. 100 billion neurons (all interneurons)  2. 3 layers of connective tissue  3. skull, layers of connective tissue, and fluid (protect brain from injury)

4. 3 main parts of the brain:  a. cerebrum:  -largest part of brain  -interprets input from senses  -controls the movement of skeletal muscles -carries out complex mental processes (learning, remembering, making judgments) -divided into left and right halves

left brain: controls the left side of the body  -mathematical skills, speech, writing, and logical thinking

right brain: controls the left side of the body  -creativity and artistic ability

b. cerebellum:  -coordinates actions of your muscles  -helps keep your balance

c. brainstem:  -controls the body's involuntary actions  -regulates your breathing and heartbeat

C. The Spinal Cord  1. link between brain and PNS  2. has also connective tissue and water fluid like the brain  3. vertebral column protects cord

C. Peripheral Nervous System 1. How Spinal Nerves Fxn: -like a two way highway 2. Somatic Nervous System -control voluntary actions 3. Autonomic Nervous System -control involuntary actions