The Neuron. A neuron has a large cell body that contains the nucleus, threadlike extensions called dendrites, and an axon.

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1 Nervous System

2 - How the Nervous System Works The Neuron A neuron has a large cell body that contains the nucleus, threadlike extensions called dendrites, and an axon.

3 - How the Nervous System Works How a Nerve Impulse Travels For a nerve impulse to be carried along at a synapse, it must cross the gap between the axon and the next structure. The axon Bps release chemicals that carry the impulse across the gap.

4 - Divisions of the Nervous System Central Nervous System The central nervous system is the control center of the body. It includes the brain and spinal cord.

5 - Divisions of the Nervous System Peripheral Nervous System The peripheral nervous system consists of a network of nerves that branch out from the central nervous system and connect it to the rest of the body. The peripheral nervous system is involved in both involuntary and voluntary acbons.

6 Divisions of the Nervous System Central nervous system (CNS) Brain and spinal cord Integration and command center Peripheral nervous system (PNS) Paired spinal and cranial nerves carry messages to and from the CNS

7 Sensory input IntegraAon Motor output Figure 11.1

8 Central nervous system (CNS) Brain and spinal cord IntegraAve and control centers Peripheral nervous system (PNS) Cranial nerves and spinal nerves CommunicaAon lines between the CNS and the rest of the body Sensory (afferent) division SomaAc and visceral sensory nerve fibers Conducts impulses from receptors to the CNS Motor (efferent) division Motor nerve fibers Conducts impulses from the CNS to effectors (muscles and glands) SomaAc sensory fiber Visceral sensory fiber Skin Motor fiber of somaac nervous system Stomach Skeletal muscle Somatic nervous system SomaAc motor (voluntary) Conducts impulses from the CNS to skeletal muscles Autonomic nervous system (ANS) Visceral motor (involuntary) Conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands Fight or Flight Sympathetic division Mobilizes body systems during acavity Parasympathetic division Conserves energy Promotes house- keeping funcaons during rest Rest and Digest Structure FuncAon Sensory (afferent) division of PNS Motor (efferent) division of PNS SympatheAc motor fiber of ANS ParasympatheAc motor fiber of ANS Heart Bladder

9 There are three main regions of the brain that receive and process informabon. These are the cerebrum, the cerebellum, and the brain stem. - Divisions of the Nervous System The Brain

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12 What s the name of this region? What s this called?

13 - Divisions of the Nervous System Building Vocabulary Key Terms: central nervous system cerebrum autonomic nervous system peripheral cerebellum nervous reflex system brain concussion stem brain spinal somabc cord nervous system Examples: The The Nerves central cerebrum of the nervous autonomic is the division system nervous is of the the system division nervous control of system the nervous made system up involuntary of the made brain acbons. up and of the spinal brain cord. and spinal cord. The peripheral nervous system is the division of the The cerebellum blink, which coordinates is a reflex, is the a response acbons of that your happens muscles nervous and system made up of all nerves outside the central automabcally. helps you to keep your balance. nervous system. The A concussion brain stem, is a which bruiselike lies between injury of the cerebellum brain. and The spinal brain cord, is controls the part your of the body s central involuntary nervous system acbons that is located those that in the occur skull automabcally. and that controls most funcbons in the body. The spinal nerves cord of the is somaac the thick nervous column system of nervous control Bssue that links voluntary the brain acbons to most such as of the using nerves a fork in or the tying peripheral your shoes. nervous system.