Nervous System Structure and Neurons
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Questions and Answers

What are bundles of nerve fibers in the central nervous system commonly referred to as?

  • Peripheral nerves
  • Nerve tracts (correct)
  • Nuclei
  • Nerves
  • What type of neuron has an axon and a single dendrite?

  • Unipolar neuron
  • Pseudounipolar neuron
  • Multipolar neuron
  • Bipolar neuron (correct)
  • Which type of neuron is associated with olfactory epithelium?

  • Multipolar neuron
  • Bipolar neuron (correct)
  • Pseudounipolar neuron
  • Unipolar neuron
  • Which type of neuron is characterized by having many dendrites?

    <p>Multipolar neuron</p> Signup and view all the answers

    Which of the following neurons has a fused dendrite and a single axon?

    <p>Pseudounipolar neuron</p> Signup and view all the answers

    The afferent portion of a nerve cell is primarily associated with which type of structure?

    <p>Dendrite</p> Signup and view all the answers

    Trigeminal ganglia are associated with which type of neuron?

    <p>Pseudounipolar neuron</p> Signup and view all the answers

    Which structural type of neuron is most commonly found as an interneuron or association neuron?

    <p>Multipolar neuron</p> Signup and view all the answers

    In terms of structure, how do unipolar neurons primarily differ from bipolar neurons?

    <p>Bipolar have only one dendrite</p> Signup and view all the answers

    Which structure is located behind the midbrain and is known to be enveloped by the midbrain in adults?

    <p>Cerebral aqueduct</p> Signup and view all the answers

    What physiological change occurs due to the opening of sodium channels during depolarization?

    <p>Sodium ions diffuse into the cell</p> Signup and view all the answers

    Which of the following statements about depolarization is accurate?

    <p>It occurs when sodium ion channels open</p> Signup and view all the answers

    What is the consequence of sodium ions diffusing into the neuron’s cytoplasm?

    <p>The membrane becomes progressively depolarized</p> Signup and view all the answers

    Which ventricle is specifically involved in ventricle communication by way of the Foramen of Monroe?

    <p>Lateral ventricle</p> Signup and view all the answers

    What role do calcium channels play during neuronal excitation?

    <p>They allow calcium ions to enter the cytoplasm</p> Signup and view all the answers

    During action potentials, where does the depolarization primarily occur?

    <p>Along the axon at nodes of Ranvier</p> Signup and view all the answers

    What is the initial trigger for the process of depolarization in a neuron?

    <p>Sodium channel opening</p> Signup and view all the answers

    What structure informs the connection between the lateral and third ventricles?

    <p>Foramen of Monroe</p> Signup and view all the answers

    What results from the rapid change in membrane permeability during depolarization?

    <p>Sodium ions flow into the cell</p> Signup and view all the answers

    What happens to branches of a neuron if the perikaryon survives but is separated from its perikaryon?

    <p>All branches die.</p> Signup and view all the answers

    What inhibits the regeneration of CNS nerve fibers following injury?

    <p>Presence of inhibitory proteins in myelin</p> Signup and view all the answers

    Which neurotransmitter is classified as inhibitory?

    <p>GABA</p> Signup and view all the answers

    What type of synapse is most commonly observed between neurons?

    <p>Axodendritic</p> Signup and view all the answers

    Which process occurs during ionic impulse transmission between neurons?

    <p>Electrical transmission</p> Signup and view all the answers

    Why is the regeneration of injured CNS nerve fibers not possible?

    <p>Inherent properties of axons in the CNS inhibit potential growth.</p> Signup and view all the answers

    What structure in a neuron marks the site where an action potential originates?

    <p>Axon Hillock</p> Signup and view all the answers

    What characteristic is NOT associated with Golgi type II cells?

    <p>Anaxonic</p> Signup and view all the answers

    Under normal conditions, where does an action potential NOT originate?

    <p>Cell body plasma membrane</p> Signup and view all the answers

    Which sensory perception is NOT primarily somatosensory?

    <p>Smell</p> Signup and view all the answers

    True cross sections of mature myelinated nerve fibers show myelin that is characterized by:

    <p>Lamellae measuring 13 to 18 nm thick</p> Signup and view all the answers

    Which structure of the neuron is the first 50 to 100 micrometers of the axon?

    <p>Initial segment</p> Signup and view all the answers

    The statement about action potentials originating at the cell body plasma membrane is:

    <p>Always false</p> Signup and view all the answers

    Which of the following components is primarily involved in sensory reception of pain?

    <p>Nociceptors</p> Signup and view all the answers

    Golgi type II neurons can be described with which attribute?

    <p>They lack a clear axon structure</p> Signup and view all the answers

    Which of these statements about the axon hillock is accurate?

    <p>It is the most excitable part of the neuron.</p> Signup and view all the answers

    What is the primary function of pseudounipolar neurons?

    <p>Sensory signal transduction</p> Signup and view all the answers

    Which structures are classified as fiber tracts within the central nervous system?

    <p>Bundles of axons</p> Signup and view all the answers

    What is primarily found within gray matter?

    <p>Nerve cell bodies</p> Signup and view all the answers

    Which term correctly describes the cell bodies of primary sensory neurons?

    <p>Pseudounipolar neurons</p> Signup and view all the answers

    The dorsal root ganglion is primarily associated with which of the following?

    <p>Sensory neuron cell bodies</p> Signup and view all the answers

    Which structure is comprised of the cell body of a neuron?

    <p>Soma</p> Signup and view all the answers

    What type of neuron is primarily involved in modulation during sensory processing?

    <p>Pseudounipolar neuron</p> Signup and view all the answers

    Which of the following is NOT a characteristic of axons?

    <p>Receive incoming information</p> Signup and view all the answers

    What forms the basis of the structure commonly referred to as ganglia?

    <p>Groups of neuron cell bodies</p> Signup and view all the answers

    Regions in the CNS with densely packed nerve cell bodies are referred to as what?

    <p>Gray matter</p> Signup and view all the answers

    Study Notes

    Nervous System Structure

    • Bundles of nerve fibers in the central nervous system (CNS) are referred to as nerve tracts, while those in the peripheral nervous system (PNS) are termed peripheral nerves.
    • CNS fibers are organized into nuclei, while PNS fibers are categorized as peripheral nerves.

    Types of Neurons

    • Bipolar neurons have two distinct processes (one axon and one dendrite); found in the olfactory epithelium and retina.
    • Pseudounipolar neurons have one axon that splits into two branches; primarily located in the trigeminal ganglia.
    • Multipolar neurons have multiple dendrites; commonly act as interneurons/association neurons.
    • Unipolar neurons have a single process acting as an axon but lack traditional dendrites.

    Dendrites and Axons

    • Dendrites are the afferent portion of a neuron, receiving signals and directing them toward the cell body.
    • The soma (cell body) contains the organelles for the neuron. Gray matter consists largely of nerve cell bodies embedded in neuroglia.

    Fiber Tracts

    • Fiber tracts are bundles of axons within the CNS, particularly found in white matter.

    Neural Canals

    • The cerebral aqueduct, located behind the midbrain, is important for cerebrospinal fluid flow and development in adults.

    Depolarization Mechanism

    • Depolarization occurs when sodium channels open, allowing Na ions to enter the neuron, changing membrane permeability.
    • Excitation triggers a rapid influx of sodium ions, leading to membrane depolarization.
    • Action potentials are generated at the axon hillock, the most excitable region of the axon.

    Somatosensory System

    • Touch and pain are part of the somatosensory system. Smell and taste are exceptions as they do not fit traditional sensory receptor pathways.

    Golgi Type II Cells

    • Golgi type II cells are generally characterized by having projection fibers; they are anaxonic, meaning they do not have a distinct axon.

    Neuronal Regeneration

    • In the CNS, regeneration of nerve fibers (axon tracts) is limited. If separated from the perikaryon (cell body), parts of the neuron may die. The presence of specific proteins in CNS myelin inhibits regeneration.

    Neurotransmitters

    • GABA is known as an inhibitory neurotransmitter, influencing neuron signaling and plasticity.

    Synaptic Types

    • Axodendritic synapses are the most common type, where one neuron's axon connects to another neuron’s dendrite, facilitating communication between neurons.

    Ionic Impulse Transmission

    • Ionic impulse transmission refers to the electrical signaling process occurring within neurons, essential for communication in the nervous system.

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    Neuroanatomy Quiz 1 PDF

    Description

    Test your knowledge on the structure of the nervous system and the types of neurons. This quiz covers the organization of nerve fibers in the CNS and PNS, as well as detailed characteristics of different neuron types. Challenge yourself to see how well you understand these fundamental concepts!

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