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 otherthe space in between is call the
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