Neural and Hormonal Systems

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Neural and Hormonal Systems
Will Explain Why We FEEL
Nervous
Strong
Sick
Pain
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It all Starts with the Neuron
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Neuron Structure
Neurons do NOT touch each other- the space in
between is call the synapse.
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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.

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The All-or None Response

• The idea that either the neuron fires or it does
  not- no part way firing.
• Like a gun

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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.

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Action Potential
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How Neurons Communicate
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Neurotransmitters

• Chemical messengers released by terminal buttons
  through the synapse.
• We should know at least 4 types and what they do.

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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 Alzheimers
disease.
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Dopamine

• Its function is motor movement and alertness.

Lack of dopamine is associated with Parkinsons
disease.
Overabundance is associated with schizophrenia.
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Serotonin

• Function deals with mood control.

Lack of serotonin has been linked to depression.
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Endorphins

• Function deals with pain control.

We become addicted to endorphin causing feelings.
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Agonists and Antagonists
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Sensory Neurons(Afferent Neurons)

• Take information from the senses to the brain.

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Inter Neurons

• Take messages from Sensory Neurons to other parts
  of the brain or to Motor Neurons.

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Motor Neurons(Efferent Neurons)

• Take information from brain to the rest of the
  body.

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Divisions of the Nervous System
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Sympathetic Nervous System

• Flight or Fight Response

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The Endocrine System
A system of glands that secrete hormones. Similar
to nervous system, except hormones work a lot
slower than neurotransmitters.
Hormones
Neurotransmitters
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The Major Endocrine Glands