Nervous System

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Nervous System
Communication Network Control Center

• Chapter 16 Lesson 1 2

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Functions

• Controls all of your bodys actions and functions
• Senses changes in out of body
• Allows the body to respond quickly

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Structures
CNS
PNS
Receives analyzes info from PNS and responds
Gathers info from in/outside of body
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Central Nervous System

• Maintains all bodily functions to keep you alive
• Dependent on environment youre in
• Temperature, appetite, breathing
• Source of thoughts, emotions, memories
• Brain
• 100 billion neurons (nerve cells)
• 29 ounces of blood pass through every minute
• Right controls left side of body, left controls
  right
• Spinal cord
• Stops growing at 5 yrs old
• Can work independently of brain by sending our
  responses directly to muscles

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Peripheral Nervous System

• Nerves that branch out in pairs from CNS to rest
  of body (muscles, skin, internal organs, glands)
• Gathers info from inside and outside of body
• CNS receives and analyzes info and initiates
  response
• 2 Subdivisions
• Autonomic Nervous System
• Involuntary functions
• (sweating, digestions, heart rate)
• Somatic Nervous System
• Voluntary responses
• (holding a pencil) skeletal muscles

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PNS
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Neurons

• Neurons (nerve cells)
• Cant replace themselves
• If it is damaged or degenerates the cell dies

Nerves
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3 Types of Neurons

• Sensory
• Messages go from sense receptors (ex. Skin) to
  the CNS
• Stomach hunger pains
• Esophagus pharynx gag reflex
• 5 senses see, taste, touch, hear, smell
• Motor
• Messages go from CNS to muscles or glands
• Interneurons
• Form electrical connections within the CNS itself

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TB Page 365
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Parts of a Neuron
Dendrites receive impulses from a neuron
Cell Body contains nucleus which processes
impulses
Axon send impulses to another neuron Lengths of
axons
fraction of an inch to several feet
Neurotransmitters chemicals that are used to
allow cells to communicate with one another
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Neurotransmitters
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Axon
Neurotransmitters
Dendrite
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What is a nerve? A bundle of axons
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Spinal Cord

• Protected by
• Vertebrae (bones)
• Cerebrospinal fluid (shock absorber)
• Connective membranes (spinal meninges)

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Brain

• Receives and process messages
• Protected by bones membranes
• Functions
• Produces electrical chemical signals

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3 Parts of the Brain1. Cerebrum

• 2 halves cerebral hemispheres
• Right controls left ½ of body and left controls
  right
• Left language, logic, math, analysis, critical
  thinking
• Right imagination, visual, emotions
• Functions
• Conscious thought and
• intellectual activities such as
• calculating,analyzing, concluding,
• identifying

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2. Cerebellum

• Functions
• Posture, balance, coordinates skeletal muscle
  movement

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3. Brain Stem

• 3 inch long stalk of nerve cells and fibers
• Functions
• Involuntary Breathing, heartbeat eye reflexes
  (pupils dilate)

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Peripheral Nervous System

• Peripheral Located away from the center
• Nerves that fan out from the CNS to muscles,
  skin, internal organs, glands
• 2 subdivisions
• Autonomic NS
• Involuntary Responses sweating, digestion, heart
• Somatic NS
• Voluntary Responses skeletal muscles

PNS
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Autonomic Nervous System
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Care

• Exercise, nutrition, rest/sleep
• Avoid illegal drugs alcohol
• Avoid Injury
• Wear helmet, seat belt
• Careful when diving

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Problems

• Head Injuries
• Concussion temporary disturbance of brains
  ability to function
• Most common, mildest kind of injury
• Contusion bruise that may cause swelling
• Can result in coma (state of unconsciousness)

The force of a sudden, hard blow or a quick stop
may cause your brain to slide forcefully against
the inner wall of your skull and become bruised.
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• Spinal Cord Injuries
• Can cause paralysis
• Paraplegia paralysis of the legs
• Quadriplegia Injury at the neck, paralysis of
  arms legs

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Degenerative Diseases

• Degenerative
• Breakdown/deterioration of function or structure
• 1. Parkinsons Disease
• Gradually involves more more nerves in brain
• Result uncoordinated muscular movement

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Degenerative Diseases

• 2. Alzheimers Disease
• Mental deterioration
• Gradually lose
• Memory
• Powers of judgment
• Speech
• Body coordination

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Other

• Epilepsy seizure
• Reoccurring seizures
• Sudden episodes of uncontrolled electrical
  activity of the brain
• Can results from
• Chemical imbalance, head injury, brain infection,
  stroke, tumor, withdrawal from drugs/alcohol