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1. PARTS OF THE NERVOUS SYSTEM AND THEIR FUNCTIONS

4. The Central Nervous System

5. The 2 Division of the Peripheral Nerves 1.Somatic Division- Communicates with the skin and skeletal muscles. 2.Autonomic Division- communicates with smooth muscles, heart muscle and glands.

6. The 2 Groups of Nerves in the Autonomic Division 1.Sympathetic Nerves- which speed up or slow down some body processes. 2.Parasympathetic Nerves- which have the opposite effect on the same body processes.

7. Neurons

8. A nerve cell or neuron is the basic unit of structure and function of the nervous system. There are three types of neurons: 1.Sensory Neurons- connect the sense organs to the central nervous system.

9. 2.Motor Neurons- carry messages from the central nervous system to muscles and glands throughout the body. 3.Interneurons or associative neurons- carry information between two neurons (sensory and motor neurons).

10. 3 Main Parts of Neurons The cell body, the dendrites and the axon. The cell body has a tiny tubelike branches called dendrites, which receive messages from the environment. The axon also called nerve fiber, is a tubelike extension of the cell body.

12. The Spinal Cord The spinal cord is a part of the central nervous system. It begins at the base of the skull and extends throughout most of the backbone, or vertebral column.

13. Structure The spinal cord is a cylinder of nerve tissue as a finger and about 45 cm long. Gray matter contains the cell bodies of motor and connector neurons. White matter contains the axons of neurons that run lengthwise through the spinal cord. The spinal cord is surrounded by membranes called meninges.

14. Function Sensory messages from the sensory organs pass upward through the spinal cord to the brain. Motor signals from the brain pass downward through the spinal cord to the neurons that lead to the glands or muscles. The spinal cord some information coming from the senses and provide motor responses that don’t come from the brain. This is called a reflex action.

15. The Brain

16. BRAIN The brain is a mass of billions of neurons. These neurons are surrounded by cells called glia which support and supply them with nutrients. Three main parts of the brain 1. The brain stem= is the lowest section of the brain which connects it to the spinal cord. 2. The cerebellum= is at the back of the brain stem and is linked to it by nerve tracts. 3. The cerebrum= it is the largest part of the brain.

17. The cerebrum is divided into sections or lobes. The four lobes are: 1. frontal 2. temporal 3. parietal 4. occipital

18. Function of the brain The brain is the body’s control center. It receives messages from and sends messages to all organs and tissues of the body. It controls both voluntary and involuntary activities. The brain gives us the ability to learn, to reason and to feel.

19. Questions: What are the functions of nervous system? How is the brain is like a computer? Why is the brain is important? What are the 2 divisions of Peripheral nerves? What are the 4 lobes of the cerebum?