Nervous Tissue and Neuron Structure Overview
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Questions and Answers

Which part of the nervous system includes everything outside of the brain and spinal cord?

  • Motor pathways
  • Central nervous system
  • Sensory pathways
  • Peripheral nervous system (correct)

    • Sensory neurons carry information away from the central nervous system.

    False (B)

    What neurotransmitter is used at the neuromuscular junction?

    Acetylcholine

    The propagation of information along an axon is known as ______.

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

    Match the following terms with their descriptions:

    <p>Afferent = Carry information towards the central nervous system Efferent = Carry information away from the central nervous system Depolarization = Reduction in the membrane potential Hyperpolarization = Increase in the membrane potential</p> Signup and view all the answers

    What is the main function of the myelin sheath in a neuron?

    <p>To insulate the axon and speed up signal transmission (A)</p> Signup and view all the answers

    Electrical signals move slower than chemical signals in neuronal communication.

    <p>False (B)</p> Signup and view all the answers

    What type of ion channel opens in response to a change in membrane potential?

    <p>voltage-gated ion channel</p> Signup and view all the answers

    The zone of the neuron where the action potential is first generated due to voltage-gated ion channels is the ______.

    <p>trigger zone</p> Signup and view all the answers

    Match the following cell types with their descriptions:

    <p>Unipolar neuron = Typically sensory neurons Multipolar neuron = Typically motor neurons and interneurons Excitatory = Increases the likelihood of an action potential Inhibitory = Decreases the likelihood of an action potential</p> Signup and view all the answers

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    Flashcards

    Central Nervous System

    The part of the nervous system that consists of the brain and spinal cord.

    Peripheral Nervous System

    The nervous system outside the central nervous system, encompassing all other neural elements.

    Motor Neuron

    A neuron that sends impulses from the central nervous system to muscles or glands.

    Sensory Neuron

    A neuron that receives and processes sensory information from the environment.

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    Axon

    A long, slender projection of a neuron that conducts electrical impulses away from the neuron's cell body.

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    Neurotransmitter

    Chemicals that transmit signals across a synapse from one neuron to another.

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    Depolarization

    A change in a cell's membrane potential, making it less negative and more positive.

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    Graded Potentials

    Changes in membrane potential that vary in size and can lead to action potentials.

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    Action Potential

    A rapid and temporary change in a neuron’s membrane potential that propagates along the axon.

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    Synaptic Cleft

    The small space between neurons at a synapse where neurotransmitters are released.

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    Study Notes

    Nervous Tissue Overview

    • Nervous tissue is categorized into central and peripheral components
    • Central nervous system: brain and spinal cord
    • Peripheral nervous system: all other nerve tissue

    Neuron Structure

    • Neuron structure consists of a cell body (soma), dendrites, and an axon.
    • Dendrites receive signals from other neurons.
    • The axon transmits signals away from the cell body.
    • Axon hillock: where the axon originates
    • These communicate between neurons via synapses
    • Axon terminals: branches at the end of the axon

    Neuron Types

    • Sensory neurons: carry sensory information to the central nervous system, generally unipolar.
    • Interneurons: connect sensory and motor neurons within the central nervous system, generally multipolar.
    • Motor neurons: carry signals from the central nervous system to muscles or glands; generally multipolar.

    Neuron Function

    • Neurons communicate through nerve impulses (action potentials).
    • Nerve impulses travel along the axon to the axon terminals.
    • Communication between neurons occurs via chemical or electrical synapses.

    Synapses

    • Synapses are junctions between neurons that allow communication.
    • Chemical synapses use neurotransmitters to transmit signals.
    • Electrical synapses use gap junctions for direct transmission.

    Myelination

    • Myelin sheaths insulate axons, speeding nerve impulse transmission.
    • Schwann cells form myelin sheaths in the peripheral nervous system.
    • Oligodendrocytes form myelin sheaths in the central nervous system.

    Synaptic Transmission

    • Action potential reaches the axon terminal of a presynaptic neuron
    • Voltage-gated Calcium channels open and calcium enters axon terminal
    • Triggers fusion of synaptic vesicles with the plasma membrane and neurotransmitter release into synaptic cleft
    • Neurotransmitter diffuses across synaptic cleft and attaches to receptors on post-synaptic cell or muscle cell
    • Post-synaptic cell or muscle cell depolarizes which may trigger propagation of an action potential
    • Neurotransmitter removal from the synaptic cleft required to terminate the signal.

    Action Potentials

    • Electrical signals, transmitted along the axon.

    • Depolarization: the membrane potential becomes less negative.

    • Repolarization: the membrane potential returns to a resting state.

    • Voltage-gated channels open and close to regulate the flow of ions.

    • Refractory periods: time after an action potential when the neuron cannot fire another action potential.

    • Absolute refractory period: no action potential possible.

    • Relative refractory period: more difficult to elicit an action potential

    Postsynaptic Potentials (graded potentials)

    • Excitatory postsynaptic potential (EPSP): brings membrane potential closer to threshold
    • Inhibitory postsynaptic potential (IPSP): brings membrane potential further from threshold
    • Synaptic potentials integrate to determine whether an action potential occurs.

    Temporal and Spatial Summation

    • Temporal summation: multiple signals arriving rapidly at a neuron add together
    • Spatial summation: signals arriving at different locations on the neuron add together.

    Neuromuscular Junction

    • The synapse between a motor neuron and a muscle fiber.
    • Acetylcholine (ACh) is the neurotransmitter.

    Skeletal Muscle Excitation/Contraction Coupling

    • The process by which a nerve impulse leads to muscle contraction
    • Action potential travels along the axon to stimulate the release of Acetylcholine at the neuromuscular junction.
    • Binding of ACh to its receptors opens ion channels which creates an action potential in muscle cell membrane
    • Propagation of this action potential along muscle cell membrane
    • Leads to release of calcium ions (Ca2+) from sarcoplasmic reticulum
    • The calcium ions trigger muscle contraction
    • Calcium removal leads to muscle relaxation

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    Nervous Tissue Slides PDF

    Description

    Explore the basics of nervous tissue, including its central and peripheral components. This quiz will cover the structure, types, and functions of neurons, emphasizing the communication processes within the nervous system. Test your knowledge on how sensory, motor, and interneurons operate within the central nervous system.

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