Neurons
Do Now
Do Now
 How does this relate to the Nervous
System?

Homework Due Today
Read Section 31.1
 Answer question 1-3 on page 900

Homework

Describe the function of the nervous
system?

The functions of the nervous sustem are
to collect information about the body’s
internal and external environments,
process that information and respond to
it
Homework

Describe how your peripheral nervous
system and central nervous system were
involved in a simple activity you
performed today.
Homework
Name and describe the three types of
neurons
 Sensory neurons carry impulses from the
sense organs. Motor neurons carry
impulses from the brain and spinal cord
to muscles and glands. Interneurons
process the information from sensory
neurons and send commands to other
interneurons or motor neurons

Homework

The immune system of people with
multiple sclerosis attacks myelin sheaths
in the CNS. The myelin breaks down and
scar tissue may result. How do you think
this would affect the transmission of
signals from the CNS?
Homework

What happens when a neuron in
stimulated by another neuron?

If the stimulus is grat enough, an impulse
begins that travels rapidly along the axon
toward the axon terminals, where the
impulse may be passed on to other cells
Homework

How can the level of pain you feel vary if
a stimulus causes and all-or-none
response?

Although the response is all-or-none, the
frequency of action potentials can vary
depending on the strength of the stimulus
Homework Due Next Class
Finish Worksheet
 Define:

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Peripheral Nervous System
Central Nervous System
Axon
Myelin Sheath
Threshold
Synapse
Neurotransmitter
The Nervous System

The Nervous System
The Nervous System
The Nervous System responds to
information collected from internal and
external environments
 Comprised of Peripheral Nervous System
and Central Nervous System

Central Nervous System

Consists of the brain and spinal cord
Peripheral Nervous System

All nerves and supporting cells that
collect information about the body’s
internal and external environment
PNS/CNS
Constant communication is happening
between the 2 nervous systems
 You’re walking around in the dark and
can’t see anything. Your hands are
reaching for the light switch and your
PNS relays the message of what it is
touching to the CNS, which relays back to
the PNS as to what it is supposed to be
looking for.

Neurons

All impulses (messages) are transmitted
by cells called neurons
◦ Sensory
◦ Motor
◦ Interneurons
 Process sensory information and send commands
to other neurons
Structure of Neuron
Cell Body
Largest part of a neuron
 Houses the nucleus and most of
cytoplasm

Homework Due Next Class
Finish Worksheet
 Define:

◦
◦
◦
◦
◦
◦
◦
Peripheral Nervous System
Central Nervous System
Axon
Myelin Sheath
Threshold
Synapse
Neurotransmitter