Download Nervous System

The Nervous System
Controls activities using electrical signals.
Made up of: • Brain
• Spinal Cord
• Nerves
There are two parts to the nervous system:
1. Central Nervous System (CNS): Brain & Spinal
Cord – process incoming & outgoing messages
2. Peripheral Nervous System (PNS): Nerves –
connects all neurons to the central nervous system
The Peripheral Nervous System
Neurons are specialized cells that carry electrical messages
through the body very quickly.
Electrical messages (impulses) sent to and from the
brain travel through neurons inside nerves.
There are two types of neurons:
Sensory: Gather information from around the body and
send it to the brain. Receptors detect change inside
and outside the body.(Ex. Eyes)
Motor: Send messages from the brain to the rest of the
body. They cause a reaction to occur. (Ex. Muscles
to contract)
Neuron
How do sensory and motor neurons work together?
Sensory neurons are your receptors, like skin on your
fingers.
They sense changes (heat, pain) and send a message to
the brain.
The brain interprets the messages and sends a response
to do something in the motor neurons (move your hand
off of the stove).
Nerves are groups of neurons that work together to send
messages.
The Central Nervous System
Sends and receives electrical messages to and from the body.
Made up of:
• Brain
• Spinal Cord
The brain is the control center of the brain. It controls
voluntary and involuntary movements in the body.
Voluntary movements are actions under your control.
Involuntary movements are actions you do without
thinking.
Brain
Made up of three connected parts:
1. Cerebrum: Controls voluntary movement and detects
light, touch, odors, sound, taste, pain, hot
and cold.
Right hemisphere: controls imagination, creativity
Left hemisphere: controls speaking, reading, writing
2. Cerebellum: Controls your balance (keeps you upright).
3. Medulla: Controls involuntary movement: breathing,
blood pressure, heart rate.
Cerebrum
Cerebellum
Medulla
The Brain
The Spinal Cord
Passes information to and from the brain to
the rest of the body.
The spinal cord is surrounded by vertebrae
(protective bones).
The spinal cord allows the
brain to communicate with
the peripheral nervous
system.
A reflex is a reaction to a stimulus. Something
you do without really thinking about it. It is an
automatic response.
Ex. Blinking when someone gets near your
face.
Touching a hot stove and screaming!
Cerebrum
Central
Cerebellum
Medulla
Peripheral
Spinal cord
Spinal nerves
Cerebrum
Cerebellum
Medulla
Spinal cord
Spinal nerves