Neuron Classification and Structure Quiz
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Questions and Answers

What are the two principal types of cells in nervous tissue?

  • Astrocytes and oligodendrocytes
  • Schwann cells and satellite cells
  • Microglia and ependymal cells
  • Neuroglia and neurons (correct)
  • What is the resting membrane potential dependent on?

  • Action potential frequency
  • Neurotransmitter release
  • Differences in ion concentration and permeability (correct)
  • Size of the neuron
  • What type of potentials are brief, short-distance signals within a neuron?

  • Graded potentials (correct)
  • Synaptic potentials
  • Resting potentials
  • Action potentials
  • What do synapses transmit signals between?

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

    What are neurons?

    <p>Cells responsible for transmitting electrical signals</p> Signup and view all the answers

    Which functions are associated with the nervous system?

    <p>Sensory input, integration, and motor output</p> Signup and view all the answers

    What does the Central Nervous System (CNS) include?

    <p>Brain and spinal cord</p> Signup and view all the answers

    What does the Peripheral Nervous System (PNS) consist of?

    <p>Nerves and ganglia outside the CNS</p> Signup and view all the answers

    What are the divisions of the PNS?

    <p>Sensory and motor</p> Signup and view all the answers

    What does the sensory division of the PNS do?

    <p>Carries impulses to the CNS from sensory receptors</p> Signup and view all the answers

    What does the motor division of the PNS do?

    <p>Transmits impulses from CNS to effector organs</p> Signup and view all the answers

    What does the motor division of the PNS include?

    <p>Somatic and autonomic nervous systems</p> Signup and view all the answers

    What are the support cells in the nervous system called?

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

    Which cells are part of the neuroglia in the CNS?

    <p>Astrocytes, microglial cells, ependymal cells, and oligodendrocytes</p> Signup and view all the answers

    What are the divisions of the autonomic nervous system?

    <p>Sympathetic and parasympathetic</p> Signup and view all the answers

    What are the functions of neuroglia in the CNS?

    <p>Each type of neuroglia in the CNS has specific functions and roles</p> Signup and view all the answers

    Which cells produce myelin sheaths around nerve fibers in the CNS?

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

    What are the main receptive regions of neurons?

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

    What is the conducting region of the neuron?

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

    What cells are vital to the regeneration of damaged peripheral nerve fibers in the PNS?

    <p>Schwann cells</p> Signup and view all the answers

    What surrounds neuron cell bodies in the PNS and has similar functions to astrocytes in the CNS?

    <p>Satellite cells</p> Signup and view all the answers

    What are the armlike extensions from the cell body of a neuron?

    <p>Neuron processes</p> Signup and view all the answers

    What is the specialized function of neurons?

    <p>Conducting messages in the form of nerve impulses</p> Signup and view all the answers

    What organelles are present in neuron cell bodies for protein synthesis?

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

    What is the protective structure for neuron cell bodies?

    <p>Skull and vertebral column</p> Signup and view all the answers

    What do neurons require for their high metabolic rate?

    <p>Continuous oxygen and glucose</p> Signup and view all the answers

    What are the distal endings of axons known as?

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

    What is the main function of dendrites?

    <p>Receiving signals from other neurons</p> Signup and view all the answers

    What is the structural classification of neurons based on the number of processes extending from the cell body?

    <p>Multipolar, bipolar, unipolar</p> Signup and view all the answers

    Which type of neuron is the most common in humans?

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

    Where are bipolar neurons typically found?

    <p>Special sense organs like the retina and olfactory mucosa</p> Signup and view all the answers

    What is the main function of unipolar neurons in the PNS?

    <p>Functioning mainly as sensory neurons</p> Signup and view all the answers

    How are neurons functionally grouped based on the direction of nerve impulse transmission relative to the CNS?

    <p>Sensory, motor, interneurons</p> Signup and view all the answers

    Which type of neuron transmits impulses from sensory receptors towards the CNS?

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

    What is the main function of motor neurons?

    <p>Carry impulses away from the CNS to effector organs like muscles and glands</p> Signup and view all the answers

    What is the function of interneurons within the CNS?

    <p>Act as association neurons within the CNS, facilitating signal integration in neural pathways</p> Signup and view all the answers

    What leads to the generation of resting membrane potential in neurons?

    <p>Differences in ion concentration and permeability across their membranes</p> Signup and view all the answers

    Which type of ion channels regulate ion movement across cellular membranes in neurons?

    <p>Chemically gated, voltage-gated, mechanically gated channels</p> Signup and view all the answers

    What determines the direction of ion movement across the neuron membrane?

    <p>Electrochemical gradients, comprising concentration and electrical gradients</p> Signup and view all the answers

    What drives the net flow of ions in and out of the neuron cell?

    <p>The balance between the chemical and electrical gradients</p> Signup and view all the answers

    What is the main function of myelin sheaths in the nervous system?

    <p>To protect and electrically insulate nerve fibers, increasing the transmission speed of nerve impulses</p> Signup and view all the answers

    What type of cells form myelin sheaths in the peripheral nervous system (PNS)?

    <p>Schwann cells</p> Signup and view all the answers

    What is the role of myelin sheath gaps in the peripheral nervous system (PNS)?

    <p>To allow for the rapid conduction of nerve impulses</p> Signup and view all the answers

    What is the main function of nonmyelinated nerve fibers in the nervous system?

    <p>To conduct nerve impulses more slowly</p> Signup and view all the answers

    In the central nervous system (CNS), what type of cells form myelin sheaths?

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

    What is the role of axonal transport in neurons?

    <p>Facilitates the movement of cellular components in both anterograde and retrograde directions</p> Signup and view all the answers

    What is the function of the initial segment of the axon in motor neurons?

    <p>To generate the nerve impulse</p> Signup and view all the answers

    What is the main function of axon terminals in neurons?

    <p>To release neurotransmitters into the extracellular space</p> Signup and view all the answers

    What is the role of motor proteins and microtubules in axonal transport?

    <p>Facilitate the movement of cellular components in both anterograde and retrograde directions</p> Signup and view all the answers

    What is the function of the Golgi apparatus in neurons?

    <p>Neurons lack a Golgi apparatus</p> Signup and view all the answers

    What is the main function of the rough endoplasmic reticulum in neurons?

    <p>To synthesize proteins for the cell</p> Signup and view all the answers

    What is the main function of myelinated fibers in nerve impulse transmission?

    <p>Conduct nerve impulses rapidly</p> Signup and view all the answers

    Which structure marks off the three primary brain vesicles during brain development?

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

    What is the general function of the basal nuclei (basal ganglia)?

    <p>Regulation of voluntary motor movements</p> Signup and view all the answers

    What is the main function of the blood-brain barrier in protecting the CNS?

    <p>Regulating the passage of substances from the blood into the brain</p> Signup and view all the answers

    What determines the complex structure of the adult brain during development?

    <p>Folding of the neural tube</p> Signup and view all the answers

    Which brain structure is associated with the Subthalamic Nuclei and substantia nigra?

    <p>Putamen and globus pallidus</p> Signup and view all the answers

    What role do basal nuclei play in muscle movements?

    <p>Filtering out incorrect responses</p> Signup and view all the answers

    What do disorders of the basal nuclei include?

    <p>Huntington's disease and Parkinson's disease</p> Signup and view all the answers

    Which brain structure forms 80% of the diencephalon and sorts sensory information to the cerebral cortex?

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

    What is the main function of the hypothalamus?

    <p>Regulating body temperature</p> Signup and view all the answers

    What are the mammillary bodies in the hypothalamus?

    <p>Relay stations in the olfactory pathways</p> Signup and view all the answers

    What does the thalamus mediate in addition to relaying sensory information?

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

    Where is the Subthalamic Nuclei located in the brain?

    <p>Basal nuclei</p> Signup and view all the answers

    What is the function of the epithalamus in the brain?

    <p>Secreting melatonin</p> Signup and view all the answers

    What is the main function of the basal nuclei?

    <p>Influencing muscle movements directed by the primary motor cortex</p> Signup and view all the answers

    What brain structure influences homeostasis and autonomic nervous system activity?

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

    What brain structure plays a vital role in overall body homeostasis?

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

    What is the main function of the hypothalamus?

    <p>Regulating body temperature, food intake, water balance, and sleep-wake cycles</p> Signup and view all the answers

    Which gland is part of the epithalamus and helps regulate the sleep-wake cycle?

    <p>Pineal gland</p> Signup and view all the answers

    What is the ultimate cause of Parkinson's disease?

    <p>Degeneration of the dopaminereleasing neurons of the substantia nigra</p> Signup and view all the answers

    Which part of the brain stem is responsible for relaying information between the motor cortex and cerebellum?

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

    What is the collective function of the midbrain, pons, and medulla oblongata in the brain stem?

    <p>Providing a pathway for fiber tracts, producing automatic behaviors, and accounting for 2.5% of total brain mass</p> Signup and view all the answers

    What is the role of the periaqueductal gray matter in the midbrain?

    <p>Involvement in pain suppression and 'fight-or-flight' response</p> Signup and view all the answers

    Which part of the midbrain is involved in visual reflexes?

    <p>Superior colliculi</p> Signup and view all the answers

    What is the function of the substantia nigra in the midbrain?

    <p>Embedded in the white matter and involved in Parkinson's disease</p> Signup and view all the answers

    What is the main function of the pons in the brain stem?

    <p>Relaying information between the motor cortex and cerebellum, and helping maintain the normal rhythm of breathing</p> Signup and view all the answers

    What is the most inferior part of the brain stem that blends gradually into the spinal cord?

    <p>Medulla oblongata</p> Signup and view all the answers

    Which nucleus in the hypothalamus regulates the sleep-wake cycles?

    <p>Suprachiasmatic nucleus</p> Signup and view all the answers

    What does the hypothalamus use to trigger the release of antidiuretic hormone for controlling water balance and thirst?

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

    Which area of the Cerebral Cortex is responsible for emotional impact and memory formation?

    <p>Limbic association area</p> Signup and view all the answers

    What is the primary function of the Anterior Association Area (prefrontal cortex) in the Cerebral Cortex?

    <p>Personality and working memory</p> Signup and view all the answers

    What is the role of the Posterior Association Area in the Cerebral Cortex?

    <p>Recognizing patterns and faces</p> Signup and view all the answers

    What is lateralization of Cortical Functioning?

    <p>Division of labor between cerebral hemispheres</p> Signup and view all the answers

    What is the function of Association fibers in the Cerebral White Matter?

    <p>Connect different parts of the same hemisphere</p> Signup and view all the answers

    Which structure is primarily involved in movement control and is located deep within the cerebral white matter?

    <p>Basal Nuclei</p> Signup and view all the answers

    What type of fibers transmit sensory information to the cerebral cortex and motor output from it?

    <p>Projection fibers</p> Signup and view all the answers

    Which fibers connect corresponding gray areas of the two cerebral hemispheres?

    <p>Commissural fibers</p> Signup and view all the answers

    What is the function of commissural fibers in the Cerebral White Matter?

    <p>Connect corresponding gray areas of the two hemispheres</p> Signup and view all the answers

    Which region of each cerebral hemisphere is responsible for communication within the cortex and with lower CNS centers?

    <p>Cerebral White Matter</p> Signup and view all the answers

    What are the myelinated fibers in the Cerebral White Matter classified as?

    <p>Association, commissural, or projection fibers</p> Signup and view all the answers

    Which structures are involved in the control of movement and are located deep within the cerebral white matter?

    <p>Basal Nuclei</p> Signup and view all the answers

    Which part of the brain accounts for about 83% of total brain mass?

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

    What is the main component of gray matter in the brain?

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

    What is the main component of white matter in the brain?

    <p>Myelinated axons</p> Signup and view all the answers

    What is the main function of the cerebral cortex in the nervous system?

    <p>Executive functions</p> Signup and view all the answers

    Which imaging techniques reveal that specific motor and sensory functions are localized in discrete cortical areas called Domains?

    <p>PET scans</p> Signup and view all the answers

    What is the basic pattern of the central nervous system (CNS)?

    <p>Central cavity surrounded by gray matter</p> Signup and view all the answers

    How are the brain ventricles filled and lined?

    <p>Filled with cerebrospinal fluid and lined by ependymal cells</p> Signup and view all the answers

    What connects the third ventricle with the fourth ventricle in the brain?

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

    Where are the occipital lobes located in the skull?

    <p>Superior to the posterior cranial fossa</p> Signup and view all the answers

    What are the three basic regions of each cerebral hemisphere?

    <p>Cortex, white matter, and basal nuclei</p> Signup and view all the answers

    What do modern imaging techniques reveal about the localization of higher mental functions in the cortex?

    <p>Functions are localized in discrete cortical areas</p> Signup and view all the answers

    What is the main function of the brain stem?

    <p>Relay information between the spinal cord and the brain</p> Signup and view all the answers

    Study Notes

    Neuron Classification and Function

    • Neurons are structurally classified as multipolar, bipolar, or unipolar based on the number of processes extending from the cell body.
    • Multipolar neurons, the most common type in humans, have three or more processes, including one axon and multiple dendrites.
    • Bipolar neurons possess two processes—an axon and a dendrite—found in special sense organs like the retina and olfactory mucosa.
    • Unipolar neurons have a single short process that divides into proximal and distal branches, functioning mainly as sensory neurons in the PNS.
    • Functionally, neurons are grouped as sensory, motor, and interneurons based on the direction of nerve impulse transmission relative to the CNS.
    • Sensory neurons, mainly unipolar, transmit impulses from sensory receptors towards the CNS, with long peripheral processes.
    • Motor neurons, multipolar, carry impulses away from the CNS to effector organs like muscles and glands.
    • Interneurons, also multipolar, act as association neurons within the CNS, facilitating signal integration in neural pathways.
    • Neurons have a resting membrane potential due to differences in ion concentration and permeability across their membranes.
    • Membrane ion channels, including chemically gated, voltage-gated, and mechanically gated channels, regulate ion movement across cellular membranes.
    • Electrochemical gradients, comprising concentration and electrical gradients, determine the direction of ion movement across the membrane.
    • The resting membrane potential is generated by the balance between the chemical and electrical gradients, driving the net flow of ions in and out of the cell.

    Neuron Structure and Function

    • Nerve impulses are generated and transmitted along the axolemma, typically away from the cell body.
    • In motor neurons, the nerve impulse is generated at the initial segment of the axon and conducted to the axon terminals.
    • Axon terminals release neurotransmitters into the extracellular space, which either excite or inhibit neurons, muscle, or gland cells.
    • Axons lack rough endoplasmic reticulum and a Golgi apparatus, relying on the cell body for protein synthesis and efficient transport mechanisms.
    • Axonal transport occurs in both anterograde (away from the cell body) and retrograde (toward the cell body) directions, facilitated by motor proteins and microtubules.
    • Myelin sheaths protect and electrically insulate nerve fibers, increasing the transmission speed of nerve impulses.
    • Myelin sheaths in the peripheral nervous system (PNS) are formed by Schwann cells, while in the central nervous system (CNS), they are formed by oligodendrocytes.
    • Myelin sheaths in the PNS contain myelin sheath gaps called Nodes of Ranvier and an outer collar of perinuclear cytoplasm (neurilemma).
    • Nonmyelinated nerve fibers associated with Schwann cells in the PNS are thin fibers and are covered by the long extensions of adjacent glial cells in the CNS.
    • Myelinated fibers conduct nerve impulses rapidly, while nonmyelinated fibers conduct impulses more slowly.
    • In the PNS, myelin sheaths are formed by Schwann cells, which wrap themselves around the axon in a jelly roll fashion, gradually squeezing out cytoplasm to form the myelin sheath.
    • Myelin sheaths in the CNS lack an outer collar of perinuclear cytoplasm, and the smallest-diameter axons are nonmyelinated and covered by the long extensions of adjacent glial cells.

    Functional and Structural Areas of the Cerebral Cortex

    • The Cerebral Cortex is divided into functional and structural areas, including the primary motor and somatosensory cortex, multimodal association areas, and anterior, posterior, and limbic association areas.
    • The Anterior Association Area, also known as the prefrontal cortex, is involved in intellect, complex learning, recall, personality, and contains working memory.
    • The Posterior Association Area plays a role in recognizing patterns, faces, spatial localization, sensory integration, and language comprehension.
    • The Limbic Association Area, which includes the cingulate gyrus, parahippocampal gyrus, and hippocampus, is responsible for emotional impact and memory formation.
    • Lateralization of Cortical Functioning involves the division of labor between the cerebral hemispheres, with the left hemisphere dominant for language, math, and logic in about 90% of people.
    • The remaining 10% may have reversed or shared hemisphere functions, and right-cerebral-dominant individuals are often left-handed.
    • The two cerebral hemispheres have almost instantaneous communication and complete functional integration, with each hemisphere having specific abilities.
    • Cerebral White Matter, the second region of each cerebral hemisphere, is responsible for communication within the cortex and with lower CNS centers, consisting of myelinated fibers classified as association, commissural, or projection fibers.
    • Association fibers connect different parts of the same hemisphere, while commissural fibers connect corresponding gray areas of the two hemispheres, with the largest commissure being the Corpus Callosum.
    • Projection fibers transmit sensory information to the cerebral cortex and motor output from it, connecting the cortex to the rest of the nervous system and the body's receptors and effectors.
    • The Basal Nuclei, deep within the cerebral white matter, are involved in the control of movement, and include the caudate nucleus, putamen, and globus pallidus.
    • The caudate nucleus, putamen, and globus pallidus are the primary structures forming the basal nuclei, and are primarily involved in movement control.

    Development and Structure of the Adult Brain

    • The adult brain is composed of four main regions: Cerebral Hemispheres, Diencephalon, Brain Stem, and Cerebellum.
    • Gray matter consists of nonmyelinated neurons and neuron cell bodies, while white matter consists mostly of myelinated axons with some nonmyelinated axons, primarily in fiber tracts.
    • The brain ventricles are filled with cerebrospinal fluid and lined by ependymal cells, and they are continuous with each other and with the central canal of the spinal cord.
    • The cerebral hemispheres are the most visible parts of the brain and account for about 83% of total brain mass.
    • The cerebral hemispheres consist of cortex, white matter, and basal nuclei, and are divided into lobes - frontal, parietal, temporal, occipital, and insula.
    • The cerebral cortex is the "Executive Suite" of the nervous system, composed of gray matter and containing billions of neurons arranged in six layers.
    • Modern imaging techniques, such as PET scans and functional MRI scans, reveal that specific motor and sensory functions are localized in discrete cortical areas called Domains.
    • The basic pattern of the central nervous system (CNS) is a central cavity surrounded by gray matter, external to which is white matter.
    • The third ventricle is continuous with the fourth ventricle via the cerebral aqueduct that runs through the midbrain.
    • The cerebral hemispheres fit snugly in the skull, with the occipital lobes located well superior to the posterior cranial fossa.
    • Each of the cerebral hemispheres has three basic regions: a superficial cerebral cortex of gray matter, internal white matter, and basal nuclei.
    • Many higher mental functions, such as memory and language, appear to be spread over large areas of the cortex in overlapping domains.

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    Description

    Test your knowledge of neuron classification, structure, and function with this quiz. Explore the different types of neurons, their functions, and the role of membrane potential in nerve impulse transmission. Dive into the structure of axons, myelin sheaths, and the process of axonal transport. Ideal for students and professionals in neuroscience, biology, or related fields.

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