Transcript Module 3

Neural and Hormonal Systems
Will Explain Why We FEEL……
Nervous
Strong
Pain
Sick
It all Starts with the Neuron
Neuron Structure
Neurons do NOT touch each other- the
space in between is call the synapse.
How a Neuron Fires
It is an electrochemical process
• Electrical inside the neuron
• Chemical outside the neuron (in
the synapse in the form of a
neurotransmitter).
• The firing is call Action Potential.
The All-or None Response
• The idea that
either the
neuron fires or
it does not- no
part way firing.
• Like a gun
Steps of Action Potential
• Dendrites receive neurotransmitter from another
neuron across the synapse.
• Reached its threshold- then fires based on the
all-or-none response.
• Opens up a portal in axon, and lets in positive ions
(Sodium) which mix with negative ions (Potassium)
that is already inside the axon (thus Neurons at
rest have a slightly negative charge).
• The mixing of + and – ions causes an electrical
charge that opens up the next portal (letting in
more K) while closing the original portal.
• Process continues down axon to the axon
terminal.
• Terminal buttons turns electrical charge into
chemical (neurotransmitter) and shoots message
to next neuron across the synapse.
Action Potential
How Neurons Communicate
Neurotransmitters
• Chemical messengers released by
terminal buttons through the
synapse.
• We should know at least 4 types
and what they do.
Acetylcholine
• Its function is motor movement and
maybe memory.
To much and you will….
Not enough and you will….
Lack of ACH has been linked to
Alzheimer’s disease.
Dopamine
• Its function is motor movement and
alertness.
Lack of dopamine is
associated with
Parkinson’s disease.
Overabundance is
associated with
schizophrenia.
Serotonin
• Function deals with mood control.
Lack of serotonin has
been linked to
depression.
Endorphins
• Function deals with pain
control.
We become addicted
to endorphin causing
feelings.
Agonists and Antagonists
Types of Neurons
Sensory Neurons
Motor Neurons
Inter Neurons
Sensory Neurons
(Afferent Neurons)
• Take information from the senses
to the brain.
Inter Neurons
• Take messages
from Sensory
Neurons to other
parts of the brain
or to Motor
Neurons.
Motor Neurons
(Efferent Neurons)
• Take information from brain to the
rest of the body.
Divisions of the Nervous System
Sympathetic Nervous System
Flight or Fight Response
A Simple Reflex
A Simplified Neural Network
Neurons that learn to work
together as a team.
The Endocrine System
A system of glands that secrete
hormones.
Similar to nervous system,
except hormones work a lot
slower than neurotransmitters.
Hormones
Neurotransmitters
The Major Endocrine Glands