Biology 235 Human Anatomy and Physiology

Study Guide

Chapter 12
Nervous Tissue

Objectives

After completing this chapter, you should be able to

  1. identify the major structures and functions of the nervous system in the maintenance of homeostasis.
  2. compare the histological characteristics of neuroglia and neurons.
  3. describe the major functions of neuroglia.
  4. describe myelination and grey and white matter.
  5. describe the cellular properties that permit communication among neurons and effectors.
  6. compare the basic types of ion channels, and explain how they relate to action potentials and graded potentials.
  7. describe the factors that contribute to the generation of a resting membrane potential.
  8. list the sequence of events involved in the generation of an action potential.
  9. describe the propagation of nerve impulses.
  10. explain the events of signal transmission at a chemical synapse.
  11. distinguish between spatial and temporal summation, and between excitatory and inhibitory neurotransmitters.
  12. describe the classes and functions of neurotransmitters.
  13. describe the various types of neural circuits in the nervous system.
  14. describe the steps in repair and regeneration of nervous tissue.
  15. outline briefly two selected disorders (homeostatic imbalances).

Keywords and Topics

Make certain that you can define, and use in context, each of the terms listed below, and that you understand the significance of each of the concepts.

  1. Identify the major structures and functions of the nervous system in the maintenance of homeostasis.
    1. nervous system
      1. organization of the nervous system
      2. central nervous system (CNS)
        1. brain
        2. spinal cord
      3. peripheral nervous system (PNS)
      4. nerve
      5. cranial nerves
      6. spinal nerves
      7. ganglion (plural is ganglia)
      8. enteric plexuses
      9. sensory receptor
      10. somatic nervous system (SNS)
      11. autonomic nervous system (ANS)
        1. sympathetic
        2. parasympathetic
      12. enteric nervous system (ENS)
      13. functions of the nervous system
        1. sensory function
        2. integrative function
        3. motor function
          1. effector
  2. Compare the histological characteristics of neuroglia and neurons.
    1. histology
      1. electrical excitability
      2. action potentials (or nerve impulses)
      3. parts of a neuron
        1. cell body
        2. Nissl bodies
        3. dendrite
        4. axon
        5. axon hillock
        6. initial segment
        7. trigger zone
        8. axon collateral
        9. axon terminal
        10. synapse
        11. synaptic end bulb
        12. varicosities
        13. synaptic vesicle
        14. neurotransmitter
        15. fast axonal transport
        16. slow axonal transport
      4. structural classification
      5. multipolar neuron
      6. bipolar neuron
      7. unipolar neuron
      8. functional classification
        1. sensory
        2. motor
        3. interneurons
  3. Describe the major functions of neuroglia.
    1. neuroglia or glia
    2. astrocytes
    3. oligodendrocytes
      1. myelin sheath
      2. myelinated
    4. microglia
    5. ependymal cells
    6. Schwann cells
    7. satellite cells
  4. Describe myelination and grey and white matter.
    1. myelinated and unmyelinated
    2. neurolemma
    3. nodes of Ranvier
    4. clusters of neuronal cell bodies—nucleus
    5. bundles of axons—tracts
    6. white matter
    7. gray matter
  5. Describe the cellular properties that permit communication among neurons and effectors.
    1. graded potentials
    2. action potentials
      1. muscle action potential
      2. nerve action potential
    3. electrical signals
      1. membrane potential
      2. resting membrane potential
      3. current
  6. Compare the basic types of ion channels, and explain how they relate to action potentials and graded potentials.
    1. ion channel
      1. electrochemical gradient
      2. leak channel
      3. ligand-gated ion channel
      4. mechanically-gated ion channel
      5. voltage-gated ion channel
  7. Describe the factors that contribute to the generation of a resting membrane potential.
    1. resting membrane potential
    2. polarized
    3. factors that contribute to the resting membrane potential
    4. graded potential
      1. hyperpolarizing graded potential
      2. depolarizing graded potential
      3. decremental conduction
      4. summation
  8. List the sequence of events involved in the generation of an action potential.
    1. action potential (AP) or impulse
    2. threshold
      1. subthreshold stimulus
      2. threshold stimulus
      3. suprathreshold stimulus
    3. all-or-none principle
    4. depolarizing phase
    5. repolarizing phase
    6. after hyperpolarizing phase
    7. refractory period
      1. absolute refractory period
      2. relative refractory period
  9. Describe the propagation of nerve impulses.
    1. nerve impulse propagation (or conduction)
    2. continuous conduction
    3. saltatory conduction
    4. factors that affect the speed of propagation
    5. classification of nerve fibers
    6. encoding of stimulus intensity
    7. comparison of electrical signals produced by excitable cells
  10. Explain the events of signal transmission at a synapse.
    1. synapse
      1. presynaptic neuron
      2. postsynaptic cell
      3. postsynaptic neuron
      4. effector cell
      5. axodendritic
      6. axoaxonic
      7. electrical synapse
      8. gap junctions
      9. advantages
      10. chemical synapse
      11. synaptic cleft
      12. postsynaptic potential
      13. synaptic delay
      14. transmission of signals at a chemical synapse—7 steps
      15. excitatory postsynaptic potential (EPSP)
      16. inhibitory postsynaptic potential (IPSP)
      17. neurotransmitter receptors
      18. removal of neurotransmitter
  11. Distinguish between spatial and temporal summation, and between excitatory and inhibitory neurotransmitters.
    1. summation
      1. spatial summation
      2. temporal summation
        1. EPSP
        2. nerve impulses
        3. IPSP
  12. Describe the classes and functions of neurotransmitters.
    1. neurosecretory cells
    2. neurotransmitters
      1. acetylcholine
        1. amino acids
        2. glutamate
        3. gamma-aminobutyric acid (GABA)
        4. glycine
      2. biogenic amines
        1. norepinephrine
        2. epinephrine
        3. dopamine
        4. catecholamines
        5. serotonin
      3. nitric oxide (NO)
      4. neuropeptides
        1. enkephalins
        2. endorphins
  13. Describe the various types of neural circuits in the nervous system.
    1. neural circuits
      1. simple series
      2. diverging circuit
      3. converging circuit
      4. reverberating circuit
      5. parallel after discharge circuit
  14. Describe the steps in repair and regeneration of nervous tissue.
    1. neurogenesis in the CNS
      1. plasticity
      2. neurogenesis
    2. damage and repair in the PNS
  15. Outline briefly two selected disorders (homeostatic imbalances).
    1. multiple sclerosis (MS)
    2. epilepsy

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