Fundamentals of Neurology

• The 3 Overlapping Functions of the Nervous System


  1. sensory input - the nervous system uses its millions of sensory receptors to monitor changes occuring both inside + ouside the body. the gathered info = sensory input
  2. integration - the nervous system processes + interprets sensory input + decides what should be done at each moment
  3. motor output - the nervous system activates effector organs - muscles + glands - to cause a response
• Central Nervous System


  CNS consists of the brain + spinal cord, which occupy the dorsal body cavity

  CNS = the integrating + control center of the nervous system

  it interprets sensory input + dictates motor output based on reflexes, current conditions + past experience
• Peripheral Nervous System


  PNS = part of the nervous system outside the CNS

  PNS consists mainly of nerves (bundles of axons) that extend from the brain + spinal cord + ganglia (collections of neuron cell bodies)

  spinal nerves carry impulses to + from the spinal cord

  cranial nerves carry impulses to + from the brain

  these peripheral nerves serve as communication line that link all parts of the body to the CNS
• Central Nervous System vs Peripheral Anatomy

  CNS vs PNS

  
• The 2 Functional Subdivisions of the PNS


  PNS has 2 functional subdivisions:

  sensory/afferent

  motor/efferent
• Sensory Subdivision of the PNS


  the sensory subdivision consists of nerve fibres (axons) that convey impulses to the CNS from sensory receptors located thru out the body

  somatic sensory fibres convey impulses from the kin, skeletal muscles + joints

  visceral sensory fibres transmit impulses from the visceral oragans (organs w in the ventral body cavity - front part of trunk - heart, lungs ...)

  the sensory subdivision keeps the CNS constantly informed of events going on both inside + outside the body
• Motor Division of PNS


  the motor division of PNS transmits impulses from the CNS to effector organs

  these impulses activate muscles to contract + glands to secrete
• Subdivisions of the Motor Division


  somatic nervous system

  autonomic nervous system
• Subdivion of the Motor Division - Somatic Nervous System


  the somatic nervous system is composed of somatic motor nerve fibres that conduct impulses from the CNS to skeletal muscles

  often referred to as the voluntary nervous system as it allows to consciously control out skeletal muscles
• Subdivision of the Motor Division - Autonomic Nervous System


  ANS consists of visceral motor nerve fibres that regulate the activity of smooth muscles, cardiac muscles + glands

  = involuntary nervous system
• Divisions of the Nervous System


  brain + spinal cord = CNS

  nerves = PNS