The Nervous System

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Control Coordination

• The Nervous System
• Neurons
• Central Nervous System
• Brain
• Spinal Cord
• Peripheral Nervous System
• The Senses

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Organization in the Body
A collection of systems
Several organs working together each system has
one major role
A distinct body part that carries out one or more
main functions
A group of similar cells that carry out a
specialized job
The basic building block of all living things,
plant or animal
Specialized structures inside a cell that have
specific functions
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The Nervous System

• Helps the body adjust to changes in your
  environment

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The Nervous System

• Stimulus
• Any change inside or outside your body that
  brings about a response
• Homeostasis
• Regulation of steady conditions inside the body

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The Nervous System

• Central Nervous System Brain Spinal Cord
• Peripheral Nervous System Nerves to rest of body

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Neurons

• Building blocks of the nervous system 
• 100 billion neurons in your brain alone
• 30,000 on a pinhead
• They communicate with each other thousands of
  times a second.
• Bundles of neurons make up NERVES

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3 Types of Nerve Cells

• Sensory Neurons
• Receive information form a sensory receptor and
  send impulses to the CNS
• Interneurons
• Relay impulses from sensory neurons to motor
  neurons
• Motor Neurons
• Carry impulse from the CNS to muscles and glands
  through out the body

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Parts of a Neuron

•  3 MAIN PARTS
• Dendrites - receive messages from other neurons
• Cell Body nucleus is found here
• Axon - sends messages to other neurons

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Parts of a Neuron
Dendrites
Cell Body
Axon
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Synapse

• Space between each neuron
• Neurotransmitters are the messengers that travel
  across each synapse
• They are chemical signals that neurons use to
  talk to each other, which is what makes your
  brain work. They help determine how you feel,
  think and act.

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Neurotransmitters

• Serotonin - involved in mood (such as helping you
  to feel happy), sleep, mental health, blood
  pressure and heartbeat.
• Dopamine - important in helping to regulate
  physical movement, pleasure, and thought.
• Missing in patients with Parkinson's Disease.

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Neurotransmitters

• Acetylcholine - involved in regulating muscles,
  memory, mood, sleep, and organs (like the heart).
• Lowered amounts associated with Alzheimers
  Disease

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Central Nervous System(C.N.S.)
BRAIN
SPINAL CORD
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Cerebrum

• Largest part of the brain
• Interprets impulses from the senses
• Responsible for
• thinking and learning
• creativity
• five senses
• memory and emotion
• problem-solving
• decisions

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Cerebellum

• Coordinates voluntary muscle movement
• Helps maintain balance
• When a ball is thrown to you, the cerebellum
  coordinates the proper response to prevent injury

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Brainstem

• Controls involuntary actions
• Connects the brain to the spinal cord
• Regulates heart rate, breathing, swallowing,
  blinking, and more 
• Made up of
• the midbrain
• pons
• medulla

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Spinal Cord

• Made up of bundles of neurons
• Carries impulses to and from the brain
• Together, the brain and spinal cord make up the
  Central Nervous System (C.N.S.)
• Fun fact
• The spinal cord is about 45 cm long in men and 43
  cm long in women.

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Peripheral Nervous System(P.N.S.)

• Connects the C.N.S. with the rest of the body
• sensory nerves take impulse from stimulus
  (sensory receptors) to the the CNS
• motor nerves take impulse from the CNS to the
  muscles and glands that take action.

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Reflex

• REFLEX
• An involuntary, automatic response to a stimulus
  controlled by the spinal cord
• Like when the doctor uses the rubber mallet on
  your tendon below your knee
• Movement when someone unexpectedly throws
  something at you

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Reflex Arc

• When the body receives a painful stimulus
  (stepping on a nail, touching a hot surface,
  etc), the body responds super-fast.
• Reflex Arc
• A short-cut an impulse takes for a quicker
  response
• Path of reflex arc
• STIMULUS ?sensory receptor ?sensory nerve ?spinal
  cord (interneuron) ?motor nerve ?muscle
  ?RESPONSE
• An impulse continues up to the brain to be
  interpreted by the cerebrum, BUT, meanwhile the
  affected area has already produced a response!

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Autonomic Nervous System(part of the P.N.S.)
EXTRA

• Fight or flight
• Often referred to as your 'fight-or-flight'
  system, your sympathetic nervous system prepares
  your body for emergencies. It shunts your blood
  to your muscles and increases your blood
  pressure, heart rate and breathing rate, enabling
  you to cope with stressful situations.
• Rest and digest
• Your parasympathetic nervous system maintains and
  restores your energy. It directs blood to your
  digestive tract and makes sure you actively
  digest food. It also maintains your blood
  pressure, heart rate and breathing rate at a low
  level. That's why it is sometimes called your
  'rest and digest' system.

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Fight or flight
Return to normal
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Senses

• Vision
• Sensory Receptors
• Rods sense brightness
• Cones sense color

The retina, in the back of your eye, has cells
that are sensitive to light. They connect
directly to your brain.
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Senses

• Hearing
• Sound waves make your eardrum vibrate.
• Small bones in your ear vibrate (hammer, anvil,
  stirrup)
• Vibrations go through the snail-like cochlea,
  which turns them into nerve impulses to your
  brain.

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Senses

• Taste
• 10,000 taste buds in your mouth
• Your tongue picks up four types of taste
• sweet
• sour
• bitter
• salty
• Sweet and salty are least sensitive
• Bitter ones are most sensitive

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Senses

• Smell
• Odor particles drift into your nose
• Stimulate sensory receptors olfactory cells
  in nasal passages
• Sensory receptors send impulses to your brain to
  be interpreted.

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Senses

• There are at least six types of touch receptors
  in your skin
• Hot
• Cold
• Pain
• Pressure
• Touch
• Fine touch

Touch
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Questions

• What are the main parts of the brain? What is the
  function of each?
• Describe a neuron What is it? What types are
  there? What are the parts of a neuron?
• What is the central nervous system?
• What is the peripheral nervous system?

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Questions

• What is a stimulus? Response?
• An involuntary, automatic response to a stimulus
  is what? What path does the impulse take?
• Define homeostasis.

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Helpful Resource

• http//www.morphonix.com/software/education/scienc
  e/brain/game/specimens/specimens.html