Transcript Nervous System - Effingham County Schools

Nervous System
Major Function
• To control all activities of
the body
Diversity of Nervous Systems
Simple, slow moving animals like hydra have neurons arranged in a network
of bipolar neurons called a nerve net.
Basic Tasks of the Nervous System
Sensory Input:
Monitor both
external and internal
environments.
Integration: Process
the information and
often integrate it with
stored information.
Motor output: If
necessary, signal
effector organs to
make an appropriate
response.
The Central Nervous System
• The CNS or central
nervous system consists
of the brain and spinal
cord
The Brain- The control
Center, Coordinates all
body functions
Spinal Cord – transmits
messages between the
brain and the rest of the
body.
Peripheral Nervous System
• Consists of nerves
that relay messages
between the CNS
and the rest of your
body
You have a nerve along your whole arm.
The “funny bone” is the only place on
the arm where the nerve is not
protected.
The “funny bone” is on the elbow.
Neurons
• Nerve cell that
transports signals
• Cell body: functional
portion
• Dendrites: short
extensions that receive
signals
• Axon: long extension
that transmits impulses
away
Neuron
Myelinated Neurons
• Many vertebrate peripheral neurons have an insulating sheath around
the axon called myelin which is formed by Schwann cells.
• Myelin sheathing allows these neurons to conduct nerve impulses
faster than in non-myelinated neurons.
• These nerves transmit
information relating to
smell, taste, sight,
sound, touch, and
balance back to the
brain
The Nervous System
• The nerves in the
human hand
1. Motor nerve fibers
– allow movement
2. Sensory nerve
fibers allow you to
feel…
The Brain
• Brain is the control
center of the
Nervous System
* The Brain has three main parts…
1. The Cerebrum
2. The Cerebellum
3. The Brain Stem
* The Cerebrum is the largest part of
the brain.
1. The cerebrum controls your thinking.
2. The cerebrum controls your memory.
3. The cerebrum controls your speaking.
4. The cerebrum controls your movement and identifies
the information gathered by your sense organs.
The Brain
• Cerebrum- Largest
part of the brain;
made of several
parts.
Cerebrum Parts Include…
Hypothalamusregulates temperature of
blood, appetite and
emotions.
Cerebral CortexInterprets signals from
the eyes, ears, hands,
and nose; controls
muscle movement, and
is responsible for
intelligence.
* The cerebellum is below and to the
back of the cerebrum.
1. The cerebellum controls you balance.
2. The cerebellum controls your posture.
* The Brain Stem connects the brain to
the spinal cord.
* The nerves in the brain stem control
your heartbeat, breathing, and blood
pressure.
The Brain
• Brain Stem- Controls
breathing and heart
beat.
• Cerebellum- controls
sense of balance and
coordinates the actions
of muscles.
Nervous System Disorders
Multiple Sclerosis- Disorder in which the
myelin surrounding neurons deteriorate
making it hard for signals to travel from one
neuron to the next.
Symptoms include: loss of
motor skills, blindness,
numbness, and loss of
balance.
Caused by white
blood cells attacking
the nervous system
Nervous System Disorders
Alzheimer Disease- Degeneration of nervous
tissue that can cause memory loss, loss of
verbal communication, and motor skills.
Nervous System Disorders
Huntington’s Disease- genetic disorder that
affects muscle coordination and causes
involuntary twitching.
Tourette’s Syndrome- irregular movements
of the head, neck, or shoulders. They also
may be more complex motor behaviors such
as snorting, sniffing, and involuntary
vocalization
Did you Know?
• There are more nerve cells in the human
brain than there are stars in the Milky Way.
• If we lined up all the neurons in our body it
would be around 600 miles long.
• There are 100 billion neurons in your brain
alone.
• A newborn baby's brain grows almost 3
times during the course of its first year.
Did you know?
• The left side of human brain controls the right side
of the body and the right side of the brain controls
the left side of the body.
• Only four percent of the brain's cells work while
the remaining cells are kept in reserve.
• Neurons are the largest cells in the human body.
(They can be up to 3 feet long)
• The Nervous System can transmit impulses as fast
as 100 meters per second.