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Nervous System and Nervous Tissue Chapter 11 Unit 3

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Terms in this set (22)

  • What are the three main functions of the nervous system?
    Sensory input (gathering information), Integration (processing and interpretation), and Motor output (activation of effector organs).
  • What are the two main divisions of the nervous system?
    Central nervous system (CNS) consisting of brain and spinal cord, and Peripheral nervous system (PNS) consisting of nerves outside the CNS.
  • What are the two functional divisions of the Peripheral Nervous System (PNS)?
    Sensory (afferent) division that conveys impulses to CNS, and Motor (efferent) division that transmits impulses from CNS to effectors.
  • What are the subdivisions of the motor (efferent) division of the PNS?
    Somatic nervous system (voluntary control of skeletal muscles) and Autonomic nervous system (involuntary control of smooth muscle, cardiac muscle, and glands).
  • What are the two subdivisions of the autonomic nervous system?
    Sympathetic (mobilizes body systems during activity) and Parasympathetic (conserves energy and promotes housekeeping functions during rest).
  • What are the two principal cell types in nervous tissue?
    Neuroglia (supporting cells) and Neurons (excitable cells that transmit electrical signals).
  • Name the six types of neuroglia and their locations.
    Astrocytes, Microglial cells, Ependymal cells, Oligodendrocytes (all in CNS), and Satellite cells, Schwann cells (in PNS).
  • What are the main functions of astrocytes?
    Support neurons, regulate chemical environment, guide neuron migration, respond to nerve impulses, and participate in information processing.
  • What role do microglial cells play in the CNS?
    Act as defensive cells by monitoring neurons and transforming to phagocytize microorganisms and neuronal debris.
  • What is the function of ependymal cells?
    Line brain and spinal cord cavities, circulate cerebrospinal fluid (CSF), and form a permeable barrier between CSF and CNS tissue fluid.
  • How do oligodendrocytes contribute to nervous system function?
    They form myelin sheaths around CNS nerve fibers, insulating them and increasing impulse transmission speed.
  • What are the functions of Schwann cells and satellite cells in the PNS?
    Schwann cells form myelin sheaths around peripheral nerve fibers; satellite cells surround neuron cell bodies and support them.
  • What are the key characteristics of neurons?
    Long-lived, amitotic, high metabolic rate, with a cell body and one or more processes for conducting impulses.
  • What is the function of the neuron cell body (soma)?
    Biosynthetic center synthesizing proteins and membranes; contains nucleus and organelles.
  • What are dendrites and their function?
    Short, branched processes that receive signals and convey them toward the neuron cell body as graded potentials.
  • Describe the structure and function of an axon.
    Single long process that generates and transmits nerve impulses away from the cell body to axon terminals for neurotransmitter release.
  • What is axonal transport and its directions?
    Movement of molecules and organelles along axons; anterograde (away from cell body) and retrograde (toward cell body).
  • What is the myelin sheath and its function?
    A whitish, segmented sheath around axons that protects, insulates, and increases nerve impulse speed.
  • How is myelin formed in the PNS?
    By Schwann cells wrapping their plasma membrane around axons in a jelly-roll fashion, forming concentric layers.
  • How does myelination differ in the CNS compared to the PNS?
    In CNS, oligodendrocytes form myelin sheaths with multiple flat processes wrapping several axons; no outer collar of cytoplasm is present.
  • What are the three structural classes of neurons?
    Multipolar (most common, many dendrites, one axon), Bipolar (one dendrite, one axon), and Unipolar (single short process dividing into two branches).
  • What are the three functional classifications of neurons?
    Sensory (afferent) neurons transmit impulses to CNS, Motor (efferent) neurons carry impulses from CNS to effectors, and Interneurons connect sensory and motor neurons within CNS.