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Neurons
I bet your neurons are all fired
up now!
The Nervous System
Neuron =
• Example:

Nerve =
•
Example:
Types of Neurons
•
- carry
outgoing messages from the brain and spinal
cord to the muscles and glands
– Example:
•
- neurons
within the brain and spinal cord that
communicate internally and between
sensory inputs and motor outputs
– Example:
•
-
carry messages from tissues and sensory
organs to the brain and spinal cord for
processing
– Example
Think Pair Share
• Explain which neuron’s are at
work when you swat a mosquito
• Which neurons are at work when
you pick up a fork?
Neurons
How neurons communicate
Electro-Chemical process
1. Electrical – within a neuron
–
– brief electrical charge
that sends a message down the neuron
•
Information is pushed through the axon based on process of
positive and negative charges of electrical atoms (ions)
2. Chemical – between neurons
–
travel across the
:
different ones send different messages on to the
next neuron
•
Neurotransmitters can either excite (fire) or inhibit (prevent
firing)
Step 1 :
70mv)
–
–
Step 2:
How does a neuron fire
membrane
– neuron is charged and ready to fire (-
– positive outside, negative inside
– gates do not allow sodium ions to pass through the cell
– the minimum energy needed to generate an action potential
(-55mv)
–
- the process of making a neuron more likely to generate an action
potential (excitatory neurotransmitters binding to receptors) must be
greater than
–
– the process of making the neuron less likely to generate an action
potential (inhibitory neurotransmitters binding to receptors)
Step 3:
– brief electrical charge that travels down the neuron
–
rushes in creating a positive charge on the
inside of the cell membrane.
–
– neurons can only send message in one direction at the
same speed and strength
–
flows out of the cell membrane, reversing
the polarity
Step 4:
the recharging period that must occur to ready a
neuron to generate another action potential
–
Sodium/Potassium pumps push
back to resting potential
out and
in bringing axon
Action Potential
Electrical Transmission –
The Action Potential
http://www.outreach.mc
b.harvard.edu/animatio
ns/actionpotential_shor
t.swf
Between Neuron Communication
•
– the chemical messengers that
carry information across the synapse between one neuron and
then next are released from terminal buttons on the sending
neuron Can be:
–
– make the neuron receiving neuron
more likely to generate an action potential
–
– make the neuron receiving
neurotransmitters less likely to generate an action potential
– the small gap between neurons which
neurotransmitters travel across to send a message to the
receiving neuron’s dendrites
•
– the process of the sending neuron’s terminal
buttons taking back excess neurotransmitters from the synaptic
gap
•
How do neurons communicate with
each other?
The chemical process
How Neurons Communicate
Synaptic Transmission
http://learn.genetics.utah.edu/
content/addiction/crossingdivi
de/
Think Pair Share
1. Put the following terms in order as they occur.
2. Identify which are part of the “electro” (E) part and
which are part of the “chemical part” (C)
3. Briefly describe the electro-chemical process of
neural transmission:
– Resting potential
– Synapse
– Action potential
– Repolarization
– Refractory period
– All-or-None
– Threshold
– Excitation
– Inhibition
– Reuptake
– Depolarization
Drugs can be…..
• Agonists• Antagonists• Reuptake Inhibitors-
Acetylcholine (ACH)
• Too much and you will______
• Too little and you will_______
•
disease – lack
of AcH
• Black widow –
AcH
• Botox –
AcH
• Curare –
AcH
Dopamine
Serotonin
•
•
Endorphins
Norepenephrine
•
GABA
• Inhibition of Brain
Activity
– Major
neurotransmitter -
Glutamate
• Excitation of Brain
Activity
– Major
neurotransmitter -
Agonists and Antagonists
http://thebrain.mcgill.ca/flash/i/i_03/i_03_m/
i_03_m_par/i_03_m_par_cocaine.html#dro
gues
Agonist and Antagonists
Examples:
Agonists:
Opiate Drugs (Heroin, Morphine) Black Widow Spider Venom –
Alcohol
Antagonists – Botulin, Curare
The Nervous System
Central Nervous System
• Brain
• Spinal chord
Peripheral Nervous System
• All nerves that are
not encased in bone.
• Everything but the
brain and spinal
cord.
•
•
Somatic Nervous System
• Controls
• Uses
neurons.
• What are two
examples of you
using your Somatic
Nervous System
Autonomic Nervous System
• Controls the
–
•
• What are two examples
of you using your
Autonomic Nervous
System
Sympathetic Nervous System
•
– Arouses and expends
energy
• Causes:
• What are two examples
of you using your
Sympathetic Nervous
System
Parasympathetic Nervous System
•
– Automatically slows the body
down after a stressful event.
• Causes:
• What are two examples of
you using your
Parasympathetic Nervous
system
Reflexes
• Reflex –
A Simple Reflex
Think Pair Share
• Which part of your nervous system and which
neurons would you rely on most heavily to
cross the street?
• Which part of your nervous system and which
type of neuron’s would you use when Ms.
Short arrives at your class and calls you out to
the hall, then sends you back to class.
A Simplified Neural Network
Neural Network –
Neurons learn to work together as a team.
Neurons that fire together, wire together =
learning
The Endocrine System
•A system of glands that secrete
hormones.
•Similar too Neurotransmitters
Neurotransmitters Hormones
Neurotransmitters
Location
Speed
Hormones
Pineal Gland –
Master Gland:-
Parathyroid hormone
Figure 3A.11 The endocrine system
© 2011 by Worth Publishers