The Nervous System

Health 7 – Mr. Green

Jobs of the Nervous System

1. Gathers information

2. Responds to information

3. Maintains homeostasis

Major Parts of the Nervous System

Brain - the main control center

Spinal Cord - the main highway

Nerves (Neurons) - the signal carriers

Let’s Think About Our Senses

• Your senses: sight, hearing, smell, touch,and taste are directly connected to yournervous system, and all are important…• Which of these 5 would you be most willingto give up? Why• Which of these 5 would you be least willingto give up? Why• Rank them from 1 to 5 (with 1 mostimportant to you)

Stimulus & Response

Stimulus (singular form, plural form would be stimuli)

– Any change (inside or outside the body)that brings about a response. Or anyinformation that your 5 senses gather and causesa change.

– Examples: bright light causes you to squint, a hot object causes you to pull back, dust causes you to sneeze.

Stimulus & Response

Response

- What you do as a response or reaction to a stimulus.

Homeostasis

The body’s way of keeping everything that is going on inside of it balanced and normal. When things happen outside of the body, or inside the body that throws that balance off, our body needs to respond to get everything back on track.

Example – Sweating when hot, shivering when cold.

Nerve Cell or Neuron

The cells that make up the different parts of the nervous system. They gather information (senses), transfer information, and carry out responses to information.

Types of Neurons

Sensory Neuron – Attach to our senses and gather information.

Motor Neuron – Get directions from the Central Nervous System and make us move as directed.

Interneuron – Make up brain and spinal cord and pass info back and forth between sensory, and motor neurons and the central nervous system.

Parts of the Neuron

Dendrites – Receive information from other cells.

Cell Body – Where nucleus is located.

Nucleus – Brain of the cell.

Axon – Part of the cell the nerve impulse or message travels down to leave the cell.

Axon Tips – Where nerve impulse is finally released.

Types of neurons

Nerve Impulse Action

Make-A-Nerve Activity

Each team gets 3 pipe cleaners. Your task is to use the 3 pipe cleaners to create your own nerve cell that includes a cell body, dendrites, axon and axon tips.

Each member of the group will present the cell to the class and name the 4 parts that you were asked to include.

Nerve Impulse Action

Nerve Impulse – Electrical messages being passed through the nervous system.

Synapse – Space between a neuron and the next neuron or next structure.

Neurotransmitters – Chemicals released into the synapse that allow nerve impulses to travel over the “gap”.

• New and different experiences help you build more and more neural pathways (connections between dendrites and axon tips in the brain)

• What role do schools play in developing these neural pathways

• What can you do to make sure your brain looks more like the pic on left & less like pic on the right?

Nervous System BreakdownThe nervous system can be divided into two main segments

Central Nervous System (CNS)

Peripheral Nervous System (PNS)

Central Nervous System

Made up of the brain and the spinal cord

http://teacherweb.com/TX/FriendswoodJrHigh/Webb/Nervous-System-powerpoint.pdf