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Anatomy & Physiology: Nervous System Overview and Histology

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

    Sensory input: gathers information from sensory receptors.
    Integration: processes and interprets sensory input.
    Motor output: activates muscles and glands to respond.

  • What are the two main structural components of the nervous system?

    Central Nervous System (CNS): brain and spinal cord.
    Peripheral Nervous System (PNS): cranial and spinal nerves connecting CNS to body.

  • How is the Peripheral Nervous System functionally divided?

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

  • What are the two subdivisions of the motor division of the PNS?

    Somatic nervous system: controls voluntary skeletal muscles.
    Autonomic nervous system: regulates involuntary functions of organs and glands.

  • Name the four types of neuroglia in the CNS and their functions.

    Astrocytes: support neurons and exchange nutrients.
    Microglial cells: defensive, phagocytic.
    Ependymal cells: line CNS cavities, circulate CSF.
    Oligodendrocytes: form myelin sheaths around CNS axons.

  • What are the two types of neuroglia in the PNS and their roles?

    Satellite cells: surround neuron cell bodies, support.
    Schwann cells: form myelin sheaths around PNS nerve fibers.

  • List key characteristics of neurons.

    Excitable cells that transmit electrical impulses, extreme longevity, amitotic, and high metabolic rate requiring oxygen and glucose.

  • What are the main parts of a neuron?

    Cell body (soma): contains nucleus.
    Dendrites: receive signals.
    Axon: transmits impulses to terminals.

  • What is the function of dendrites?

    Receptive regions that receive signals from other neurons and convey them toward the cell body.

  • What is the function of the axon?

    Conducts nerve impulses away from the cell body to axon terminals for communication with other cells.

  • What is the myelin sheath and its function?

    A fatty, whitish substance that insulates axons and increases the speed of nerve impulse transmission.

  • How do Schwann cells contribute to myelination in the PNS?

    They wrap around axons in a jelly roll fashion, each forming one segment of the myelin sheath.

  • What are myelin sheath gaps (nodes of Ranvier)?

    Gaps between adjacent Schwann cells where the axon membrane is exposed, facilitating rapid impulse conduction.

  • How do oligodendrocytes myelinate axons in the CNS?

    Each oligodendrocyte extends processes that wrap around multiple axons, forming myelin sheaths without an outer collar of cytoplasm.

  • What is the difference between white matter and gray matter in the CNS?

    White matter: dense collections of myelinated fibers.
    Gray matter: neuron cell bodies and nonmyelinated fibers.

  • Describe the structural classification of neurons.

    Multipolar: 3+ processes, most common.
    Bipolar: 2 processes, rare.
    Unipolar: single T-shaped process, sensory neurons.

  • What is the functional classification of neurons?

    Sensory (afferent): transmit impulses to CNS.
    Motor (efferent): carry impulses from CNS.
    Interneurons: connect sensory and motor neurons within CNS.

  • Where are sensory neuron cell bodies located?

    In ganglia of the Peripheral Nervous System (PNS).

  • What type of neurons are most interneurons?

    Multipolar neurons that shuttle signals within the CNS.

  • What is the role of microglial cells in the CNS?

    They act as defensive cells, monitoring neurons and becoming phagocytic when neurons are injured.