Download The Nervous System - ESC-2

The Nervous System
Central Nervous System
Peripheral Nervous System
Procedure
1. A starting person will be chosen and
will be given an object.
2. Once the teacher gives the signal, the
start person will pass the object to
their right.
3. Each student will take the object and
pass it to their right until it makes it
back to the starting person.
Procedure
4. DO NOT THROW THE OBJECT!
5. A time will be recorded for each trial
6. Repeat the process 2 more times and
record the times in your spiral.
Questions
• In your spiral, answer the following
questions about the demonstration.
Functions of the Nervous
System
• Your nervous system controls the
actions and reactions of the body in
response to stimuli.
– receives information
– responds to stimuli
– maintains homeostasis
Maintaining Homeostasis
• The nervous system maintains
homeostasis by directing the body to
respond correctly to the information it
receives.
– When you are hungry, your brain tells you
to eat
Central
Nervous
System
Vocabulary
Word!
• central nervous system –
composed of the brain and
spinal cord.
– brain – receives and
processes information from
inside and outside your
body.
– spinal cord – thick column of
nerve tissue that links the
brain to nerves in the rest of
your body.
Peripheral Nervous System
Vocabulary
Word!
• peripheral nervous system network of nerves that
connects your rain to the rest
of your body.
• Made up of 43 pairs of nerves
– 12 begin in the brain
– 31 begin in the spinal cord
• One nerve in each pair goes to
the right side and one to the left
Organs of the Nervous System
• The nervous system consists of:
– brain
– spinal cord
– nerves
– neurons
– sense organs
Vocabulary
Word!
brain
• brain – receives and processes
information from inside and outside
your body.
• The skull, layers of connective tissue,
and fluid protect the brain from injury
Vocabulary
Word!
cerebrum
• cerebrum – largest part of the brain that
controls thinking, problem solving, the
senses and memories.
– reads input from the senses
– controls skeletal muscles
– In charge of learning, remembering and
making judgments
Cerebrum
• Right side
– controls left side of body
– controls creativity and artistic ability
• Left side
– controls right side of body
– Controls math, speech, writing, and logic
Vocabulary
Word!
cerebellum
• cerebellum - second largest part of
your brain that coordinates your
muscles and controls your balance.
Vocabulary
Word!
brain stem
• brain stem – connects your brain to
your spinal cord and controls
involuntary actions like breathing,
digesting and heartbeat.
Vocabulary
Word!
spinal cord
• spinal cord – a
bundle of nerves
that links your brain
and peripheral
nervous system.
• Protected by bone,
connective tissue
and fluid
Receiving Information
• Because of your nervous system, you
are aware of what is happening in the
environment around you.
• Your brain is also aware of your
internal conditions like temperature
and glucose level.
Responding to Stimuli
• After receiving information, your
nervous system analyzes the data and
causes a response.
– Putting your hand in front of your face if a
ball is coming at you.
– Increasing your heart rate when
exercising.
Responding to Stimuli
• Your nervous system works by
receiving information from inside or
outside the body and turning that info
into an electrical signal.
• The messages are sent out along
special cells called neurons.
Vocabulary
Word!
neuron - a cell that moves messages in
the form of fast-moving electrical energy
called impulses.
The Neuron
• Neurons are cells
that carry information
around your body.
• Nerve impulse - The
message a neuron
carries
The Neuron
• The cell body of the neuron has two
extensions
– dendrite – carries impulses to the cell
body. A neuron can have lots of dendrites.
– axon – carries impulses away from the cell
body. A neuron only has one axon.
• The nerve impulse begins in the
dendrite, moves to the cell body then
moves down the axon.
The Neuron
signal goes from axon to dendrite
Kinds of Neurons
• Different kinds of neurons perform
different functions
– sensory neurons
– motor neurons
Sensory Neuron
• sensory neuron –
gathers information
from the internal or
external environment
and converts each
stimulus into a nerve
impulse.
• The impulse travels
along the sensory
neuron until it reaches
an interneuron in the
brain or spinal cord
• sensory impulse
travels at 76.2 m/s
Motor Neuron
• motor neuron –
moves nerve
impulses from the
brain and spinal
cord to the rest of
the body.
• Motor impulse
travels at 119 m/s
How a Nerve Impulse Travels
• Millions of nerve impulses travel your
body each day.
• The nerve impulse travels along the
neuron in the form of electrical and
chemical signals.
How a Nerve Impulse Travels
• synapse - tiny space between a the
axon of one neuron and the dendrites
of the next.
• A nerve impulse must jump this gap.
• Axon tips release a neurotransmitter
that allows the impulse to travel the
gap.
How a Nerve Impulse Travels
Drugs and alcohol can affect the
neurotransmitters
• depressants, like alcohol and
marijuana slow reaction time
• stimulants, like meth, speed up
reaction time
The Path of a Nerve Impulse
https://www.youtube.com
/watch?v=dSkxlpNs3tU
Reflex
• reflex - is an automatic response that
occurs very rapidly and without
conscious control.
• Reflexes protect us from pain and
injury.
Reflexes
the senses
• The senses gather information for
the nervous system.
– sight
– touch
– hearing
– taste
– smell
Body systems that work with
the nervous system;
• The nervous system works with
every system in the body.
Comparing Cells to the Body
• The cell part that controls the cell is the
nucleus