Nervous & Muscular Tissue

• Nervous Tissue

  • Initiate and transmit nerve impulses from one body part to another
  • Specialized for communication by electrical and chemical signals
  • Consists of neurons (nerve cells)
• Neurons


  • Detect stimuli
  • Respond quickly
  • Transmit coded information rapidly to other cells
• Neuroglia (glial)


  • Protect and assist neurons
  • 'Housekeepers' of the nervous system
  • More numerous than neurons
• Neuron parts

  • Neurosoma (cell body)
  • Dendrites
  • Axon (nerve fibre)
• Neurosoma


  • Houses nucleus and other organelles
  • Controls protein synthesis
• Dendrites

  • Multiple short, branched processes
  • Receive signals from other cells
  • Transmit messages to neurosoma
• Axon


  • Sends outgoing signals to other cells
  • Can be more than a meter long
• Muscular Tissue

  • Contract to produce movement
  • Elongated cells that are specialised to contract in response to stimulation
  • Primary job is to exert physical forces on other tissues and organs
  • Creates movements involved in body and limb movement, digestion, waste elimination, breathing, speech and blood circulation
  • Important source of body heat
• Types of muscle


  • Skeletal
  • Cardiac
  • Smooth
• Nervous & Muscular Tissues

  Excitable Tissues
• Excitability


  • Ability to respond to stimuli by changing membrane potential
  • Developed to highest degree in nervous and muscular tissues
• Membrane potential


  Electrical charge difference (voltage) that occurs across the cell membrane
• In nerve cells; changes in voltage

  Result in rapid transmission of signals to other cells
• In muscle cells; changes in voltage

  Result in contraction, shortening of the cells
• Skeletal Muscular Tissue


  • Made of muscle fibers
  • Long thin cells
  • Most skeletal muscles attach to bone
  • Contains multiple nuclei adjacent to plasma membrane
  • Striations - Alternating dark and light bands
  • Voluntary - Conscious control over skeletal muscles
• Cardiac Muscular Tissue


  • Limited to the heart
  • Cardiomyocytes are branched, shorter than skeletal muscle fibers
  • Contain once centrally located nucleus
  • Intercalated discs join cardiomyocytes end to end - Provide electrical and mechanical connection
  • Striated and involuntary (not under conscious control)
• Smooth Muscle Tissue


  Made of fusiform myocytes lacking striations
• Smooth Muscle Tissue

  • Cells are relatively short and have one central nucleus
  • Involuntary function
  • Most is visceral muscle
• Visceral muscle

  Making up part of walls of hollow organs