Nervous System: An Introduction

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Nervous System An Introduction

• HAP
• Ms. S. Chabot

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Function of the Nervous System

• 3 overlapping functions
• Monitors changes inside and outside of the body
  these changes are called STIMULI.
• Processes and interprets changing stimuli to
  decide INTEGRATION.
• Effects a response via activating effectors
  (muscles or glands) MOTOR OUTPUT.

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Function of the Nervous System

• Receptor to collect external/internal stimuli.
• 5 senses
• Temperature control centers
• Hunger/thirst
• Control Center to integrate the
• collected information.
• Brain
• Spinal cord
• Effector to relay information
• to specific organs to initiate
• a response.
• Muscles
• glands

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Working Together

• The Nervous System works with the Endocrine
  System to provide electrical and chemical control
  of ALL body processes.

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Structural Organization
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Functional Organization
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Autonomic Continuum
Rest or Digest
Fight or Flight
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Divisions of the Nervous System

• Central Nervous System (CNS)
• Includes brain and spinal cord.
• Processes information collected by receptors.
• Acts as control center for integration and
  response.

• Peripheral Nervous System (PNS)
• All neurons outside of the CNS.
• Receptors for collection of information.
• Includes
• the special
• senses.

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Cells of the Nervous System

• 2 categories
• Neurons transmit electrical impulses
• Sensory neurons receptors
• Integration neurons integrate/think
• Motor neurons effect a change through muscles
  and/or glands
• Neuroglia Nerve glue
• Protect, insulate, and support delicate neurons

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Cells of the Nervous System

• Neuroglia Nerve Glue
• Astrocytes
• Star-shaped cell that provides a scaffold to hold
  neurons in specific locations.
• Microglial cells
• Small white blood cells that destroy pathogens
  and cell debris.
• Ependymal Cells
• Produces cerebrospinal fluid (CSF)
• Oligodendrocytes
• Insulates neurons for speedy transmission of
  electrical impulses similar to insulation for
  electrical wires.

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Cells of the Nervous System

• Neurons/Nerves
• 3 main parts
• Dendrite receives info from neighboring
  neurons.
• Cell body living portion of the
  neuroncontains the nucleus and organelles.
• Axon sends info to neighboring neurons.

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Cells of the Nervous System

• Synapse
• Space in between neighboring neurons.
• Contains neurotransmitters chemicals that are
  released to control info/activity in brain.

• Types of Synapses
• Neuron-to-NeuronFound throughout Nervous System
• Neuron-to-MuscleNeuromuscular
• Neuron-to-GlandNeuroglandular

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Bipolar Unipolar
Multipolar Anaxonic 2 extensions
1 continuous Many dendrites Cannot
tellon opposite ends extension
and single axon difference of cell
body between axon and
dendrites Found in Found in
Most numerous Found in brain Special
senses special senses in the
brain for for forming close to brain
far from brain networking
networks
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The Brain
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Divisions of the Brain

• Cerebral Cortex high order processes speech,
  language, cognition.
• Cerebellum responsible for the coordination of
  muscle activity.
• Pons relays sensory info from the cerebellum to
  the cerebral cortex.
• Medulla oblongata the primitive brain
  controls heart rate, respirations, hunger,
  thirst.
• Diencephalon important in the integration of the
  nervous and endocrine system/temperature control

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Protection of the CNS

• Meninges connective tissue outer protection
  covering of the brain.
• Dura mater
• Pia mater
• Arachnoid mater
• CSF Cerebralspinal fluid a waery substance that
  bathes the brain and cushions from trauma.
• Blood-brain barrier a tight network of capillary
  beds that act as a filter to keep substances from
  entering the circulation of the brain and spinal
  cord.

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Meninges