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Fundamentals of the Nervous System and Nervous Tissue - Anatomy & Physiologybiob

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  • What are the three overlapping functions of the nervous system?

    Sensory input: gathering information about internal and external changes.
    Integration: processing and interpreting sensory input.
    Motor output: activation of effector organs to produce a response.

  • What are the two principal parts of the nervous system?

    Central nervous system (CNS): brain and spinal cord, integration and control center.
    Peripheral nervous system (PNS): nerves outside CNS, connects CNS to body.

  • What are the two functional divisions of the peripheral nervous system (PNS)?

    Sensory (afferent) division: conveys impulses to CNS.
    Motor (efferent) division: transmits impulses from CNS to effectors.

  • What are the two subdivisions of the motor (efferent) division?

    Somatic nervous system: voluntary control of skeletal muscles.
    Autonomic nervous system: involuntary control of smooth muscle, cardiac muscle, and glands.

  • What are the two functional subdivisions of the autonomic nervous system?

    Sympathetic division: mobilizes body during activity.
    Parasympathetic division: conserves energy and promotes housekeeping functions.

  • What are neuroglia and their general function?

    Neuroglia (glial cells): small cells that surround and support neurons, providing protection, nourishment, and insulation.

  • Name the four main types of neuroglia in the CNS and one key function of each.

    Astrocytes: support neurons and exchange between capillaries and neurons.
    Microglial cells: defensive cells that phagocytize debris.
    Ependymal cells: line CNS cavities and circulate cerebrospinal fluid.
    Oligodendrocytes: form myelin sheaths around CNS nerve fibers.

  • What are the two major neuroglia of the PNS and their functions?

    Satellite cells: surround neuron cell bodies, similar to astrocytes.
    Schwann cells: form myelin sheaths around peripheral nerve fibers and aid regeneration.

  • What is a neuron and what are its special characteristics?

    Neurons are excitable nerve cells that transmit electrical signals, have extreme longevity, are amitotic, and have a high metabolic rate requiring oxygen and glucose.

  • What is the neuron cell body and its function?

    Also called soma or perikaryon, it is the biosynthetic center containing the nucleus and synthesizes proteins, membranes, and chemicals.

  • What is the difference between nuclei and ganglia?

    Nuclei: clusters of neuron cell bodies in the CNS.
    Ganglia: clusters of neuron cell bodies in the PNS.

  • What are the two types of neuron processes and their functions?

    Dendrites: receive input and convey messages toward the cell body.
    Axon: conducts impulses away from the cell body to other neurons or effectors.

  • Describe the structure and function of the axon.

    Each neuron has one axon starting at the axon hillock; it generates and transmits nerve impulses to axon terminals, which release neurotransmitters.

  • What is the myelin sheath and its function?

    A whitish, protein-lipid insulating layer around axons that protects and increases the speed of nerve impulse transmission.

  • How is myelin sheath formed in the PNS?

    Formed by Schwann cells wrapping around axons in a jelly-roll fashion; one Schwann cell forms one segment of myelin sheath.

  • How is myelin sheath formed in the CNS?

    Formed by oligodendrocyte processes that can wrap around multiple axons simultaneously; no outer collar of cytoplasm.

  • What is the difference between myelinated and nonmyelinated fibers?

    Myelinated fibers: have segmented myelin sheath, conduct impulses rapidly.
    Nonmyelinated fibers: lack sheath, conduct impulses more slowly.

  • What are the structural classifications of neurons?

    Multipolar: three or more processes, most common.
    Bipolar: two processes, rare.
    Unipolar (pseudounipolar): one T-shaped process, mainly sensory neurons.

  • What are the functional classifications of neurons?

    Sensory neurons: transmit impulses to CNS, mostly unipolar.
    Motor neurons: carry impulses from CNS to effectors, multipolar.
    Interneurons: connect sensory and motor neurons, mostly in CNS.

  • What is retrograde axonal transport and its clinical significance?

    Movement of molecules toward the cell body; some viruses and toxins use this to damage neural tissue (e.g., rabies, tetanus toxin).