Nervous System

Important Vocabulary Neuron Central nervous system Dendrite Peripheral nervous system Axon Cerebrum Sensory neuron Cerebellum Interneuron Brain stem motor neuron reflec Synapse

EXPLORE ACTIVITY pg. 677 What did you find out about their heights? How were your eyes tricked?

Response to Stimuli Any change inside or outside your body that brings a response is called a stimulus Stimuli Our bodies have internal control systems that maintain homeostasis Breathing, heartbeat,digestion

Neurons Neuron: the working unit of the nervous system A neuron is made up of a cell body and branches called dendrites Dendrites receive messages and send them to the cell body An axon carries messages away from the cell body Messages carried by a neuron is called an impulse https://www.youtube.com/watch?v=cUGuWh2UeMk&list=PLLEfSFm6js-_SjqVDF3bcG6lox9O43h_L

Types of Neurons Sensory: receive information and send impulses to the brain or spinal cord Interneurons: relay impulses from the sensory to motor neurons. There are more of interneurons than any other type Motor: conduct impulses from the brain or spinal cord to muscles or glands throughout your body.

https://www.youtube.com/watch?v=C4Gt322-XxI

Synapse Since neurons don’t touch each other, how does an impulse move from one another? Synapse: small space where an impulse moves from one neuron to another. When impulse reaches the end of the axon, a nerve transmitting chemical is released by the axon This chemical diffuses across the synapse and starts an impulse in the dendrite or cell body of the next neuron

CNS AND PNS

Central Nervous System Made up of the Brain Spinal cord All body activities are coordinated If steps on your foot, your whole body reacts

The Brain Made up of 100 billion neurons Divided into 3 parts Cerebrum Cerebellum Stem Cerebrum: divided into two large sections called hemispheres Impulses from the senses are interpretted, Memory is stored Voluntary muscle control center

The Brain Cerebellum Behind and under the cerebrum Coordinates voluntary muscle movement Maintains balance and muscle tone Stem Extends from the cerebrum and connects the brain to the spinal cord Parts: midbrain, pons, medulla Controls heartbeat, breathing, blood pressure

Peripheral Nervous System Brain and spinal cord are connected to the rest of your body by the peripheral nervous system Made up of 12 pairs of cranial nerves from your brain 31 pairs of spinal nerves from your spinal cord These nerves link your CNS with all parts of your body Spinal Nerves: made up of bundles of sensory and motor neurons Somatic System and autonomic system

Somatic and Autonomic System Somatic: consists of the cranial and spinal nerves that go from the CNS to your skeletal muscles Connect the central nervous system to the organs, muscles, and skin It is like a passageway from the environment to the central nervous system processing sensory information that arrives via external stimuli including hearing, touch and sight Autonomic: controls heartbeat rate, breathing, digestions and gland functions When salivary glands release saliva

Reflex

Drugs and the Nervous System

Activity 25-1 p. 685