The Nervous SystemMiss Charney

Northville Central School

Nervous System Functions Receives information

about what is happening to your body Stimulus - change or

signal that makes the body react

Directs the way in which your body responds to the information Response - what your

body does in a reaction

Neurons Cells that carry information

through your nervous system

Nucleus - directs the actions of the neuron

Dendrites - carry impulses toward the neuron’s cell body (can have many)

Axon - carries impulses away from the cell body (can have only one)

Types of NeuronsMotor Neuron: sends impulses to

a muscle or gland

Sensory Neuron: picks up stimuli from the internal or external environment and converts the stimulus into a nerve impulse

How An Impulse TravelsSynapse: the junction where one

neuron can transfer an impulse to another

How An Impulse Travels

How An Impulse Travels1. Nerve impulses begin when receptors

pick up stimuli from the environment2. Receptors trigger nerve impulses in

sensory neurons3. Nerve impulses pass to interneurons in

the brain4. Your brain interprets the impulses5. Impulses travel along thousands of

motor neurons6. Motor neurons send the impulses to

muscles, which carry out the response

Parts of the Nervous System

Central Nervous System Control center of the body

Brain: located in the skull, is the part of the CNS that controls most functions in the body

Spinal Cord: thick column of nervous tissue the links the brain to most of the nerves in the peripheral nervous system

Parts of the Brain Cerebrum: largest

part of the brain Interprets input from the

senses, controls movement, and carries out complex mental processes such as learning and remembering

Left half - mathematical skills & logical thinking

Right half - creativity & artistic ability

Parts of the BrainCerebellum: second

largest part of the brainCoordinates actions of

your muscles and helps you to keep balance

Parts of the BrainBrain Stem:

between the cerebellum and the spinal cordControls your body’s

involuntary actions such as breathing and heart rate

Peripheral Nervous System

network of nerves branching out from the CNS and connect to body

Somatic Nervous System: control voluntary actions such as using a fork or tying your shoes

Automatic Nervous System: control involuntary actions

Reflexes Automatic response that

occurs very rapidly and without conscious control

Reflex Pathway:1. Sensory neurons in your

fingertip detect a pain stimulus2. Nerve impulses travel to your

spinal cord3. Nerve impulses return to motor

neurons in your hand, and you pull your hand away

4. As you pull your hand away, nerve impulses travel to your brain. You feel the pain