Anatomy L7

• Nervous Sys.

  • nervous tissue
  • CNS (brain and spinal cord)
  • PNS (all nervous tissue outside of CNS)
• CNS

  • integrate, process coordinated sensory input and motor output
  • intelligence, mem and learn, emotion
• special sensory receptor

  • monitor smell, taste, vision, balance, and hearing
• visceral sensory receptors

  • monitor cardiovascular, respiratory, etc
• somatic sensory receptors

  • monitor skeletal muscles, joints, body position, skin surface, provide position sense and touch, pressure, pain, and temperature sensations
• Afferent division: incoming

  PNS to CNS
• Efferent division

  • exit
  • somatic nervous sys (SNS)- skeletal muscle
  • Autonomic nervous sys (ANS)
• ANS

  • parasympathetic and sympathetic divisions
  • smooth muscle, cardiac muscle, glands, adipose tissue
• neurons

  transferring and process info
• neuroglia

  support cells (protect neurons)
• multipolar neurons

  • more than 2 processes
• dendrites

  stimulated by environ. changes or activities of other cells
• cell body

  • contains nucleus, mito, ribosomes, and other organelles and inclusions
• axon

  • conducts nerve impulses (action potential) toward axon terminals
• axon terminals

  • affect another neuron or effector organ (muscle or gland)
• ependymal cell

  • epithelial cell that lines fluid-filled passageways w/in the brain and spinal cord
• astrocyte

  • anchor to capillaries
  • blood brain barrier- isolate CNS from general circulation
  • most common
• microglia

  • garbage can
  • phagocytes that move through nervous tissue removing unwanted substances
• oligodendrocytes

  • cells w/ sheet-like processes that wrap around axons
  • insulination
• neuroglia types

  • satellite cells- surround neuronal cell bodies
  • Schwann cells- cover peripheral axons; like oligodendrocytes; produce myelin; smooth and quick signal
• structural classification of neurons

  • based on the placement of the cell body and the number of processes that extend from the cell body
• anaxonic neuron

  • no axon
  • no stimulation from environ.
• bipolar neuron

  • rare
  • long dendrite
• pseudounipolar neuron

  • 1 axon in e/ direction
  • sensory nerve
  • axon- initial segment- dendrites
  • axon- axon terminals
• neuron functional classification

  • sensory neurons
  • motor neurons
  • interneurons
• sensory neurons

  • bring in stimulation from environ. to CNS
• motor neurons: outgoing to effectors
• interneurons

  • transmit impulses btwn sensory/ motor neurons w/ CNS and btwn neurons w/in CNS
  • control coordinated activity
• spinal cord

  • works w/ or w/o brain
  • incoming info from peripheral nerves to brain
• cervical spinal nerves- 8 nerves; extra nerve

  C7- cervical enlargement
• below cauda equina

  • strands of nerves
  • spinal tap here
• T11- lumbosacral enlargement

  L1- conus medullaris

  L4- cauda equina
• 3 meningeal layers

  • dense fibrous tissue
  • provide protection, physical stability; shock absorption
• dura mater- stabilize SC, tough, thickest layer
• arachnoid mater- line dura mater
• pia mater- bound to neural tissue, deepest layer
• btwn arachnoid mater and dura mater- subarachnoid space: CSF
• organization of gray matter: neuronal cell bodies

  • cell bodies of neurons w/in gray matter are organized into groups called nuclei
  • sensory nuclei and motor nuclei
• posterior (dorsal) horns: somatic and visceral sensory nuclei
• lateral horns (intermediate horns): visceral motor nuclei