Nervous System

• Nervous system


  One of the most complex among all the other body systems<|>Coordinates activities of body systems<|>Enables us to detect and respond to stimuli
• Stimuli


  Changes that occur within or outside the body
• Components of the nervous system

  • Brain
  • Cranial nerves
  • Spinal cord
  • Spinal nerve
  • Ganglia
  • Enteric plexus
  • Sensory receptors
• Functions of the nervous system

  • Receiving sensory input
  • Integrating information
  • Maintain homeostasis
  • Mental activity
  • Control of muscles and glands
• Brain


  • Left & right hemisphere
  • Enclosed by skull
  • 10 billion neurons
• Cranial nerves


  • Olfactory
  • Optic
  • Oculomotor
  • Trochlear
  • Trigeminal
  • Abducens
  • Facial
  • Acoustic
  • Glossopharyngeal
  • Vagus
  • Accessory
  • Hypoglossal
• Cranial nerves


  12 pairs
• Cranial nerve properties


  • Sensory
  • Motor
  • Both
• Spinal cord


  • Starts from foramen magnum to Lumbar 2
• Spinal nerves


  31 pairs<|>Emerges from spinal cord
• Ganglia


  Small masses of nerve tissue consisting primarily of neuron cell bodies
• Enteric plexuses


  Network of neurons that regulate the digestive system
• Sensory receptor


  Dendrites of sensory neuron<|>Specialized cell that monitor changes in external/internal environment
• Subdivisions of the nervous system

  • Central nervous system (CNS)
  • Peripheral nervous system (PNS)
• Neurons


  Nerve cells<|>Smallest/basic unit of nervous system<|>Excitable<|>Transmit messages from one part of the body to another<|>Receive and transmit electrical (AP or neural impulses) and chemical signals (neurotransmitters)
• Major parts of a neuron

  • Cell body
  • Processes or fibers
• Cell body


  Single nucleus (source of info for protein synthesis)<|>The neuron will die if the cell body is removed
• Processes or fibers


  • Dendrites
  • Axon
• Dendrites


  Branched fibers that receive and transmit impulses to the cell body<|>Toward/afferent
• Axon


  Transmits impulses from the cell body towards another neuron<|>Away/efferent
• Axon hillock


  Area where the axon leaves the neuron's cell body
• Classification of neurons by structure

  • Multipolar neurons
  • Bipolar neurons
  • Pseudo-unipolar neurons
• Classification of neurons by function

  • Sensory/afferent
  • Motor/efferent
  • Interneurons
• Major parts of the brain

  • Brainstem
  • Diencephalon
  • Cerebellum
  • Cerebrum