Biology Chapter Nervous System Quiz
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Questions and Answers

Which part of the nervous system is responsible for involuntary actions such as heart rate and digestion?

  • Central nervous system
  • Autonomic nervous system (correct)
  • Peripheral nervous system
  • Somatic nervous system

    • The myelination of nerve fibers increases the speed of nerve impulse transmission.

    True

    What are the two main types of postsynaptic potentials?

    Excitatory postsynaptic potential (EPSP) and inhibitory postsynaptic potential (IPSP)

    The structural unit of the nervous system is called a ______.

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

    Match the following brain structures with their primary functions:

    <p>Cerebellum = Coordination of movement Thalamus = Relay station for sensory information Hypothalamus = Regulation of homeostasis Brain stem = Control of basic life functions</p> Signup and view all the answers

    What triggers the release of neurotransmitters in the presynaptic knob?

    <p>Action potential</p> Signup and view all the answers

    Neurotransmitters can only be degraded by enzymes and cannot be taken up by the presynaptic cell.

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

    What happens after neurotransmitters bind to receptors on the postsynaptic membrane?

    <p>Cell responses occur.</p> Signup and view all the answers

    When an action potential arrives, Ca2+ channels open and __________ moves into the presynaptic knob.

    <p>Ca2+</p> Signup and view all the answers

    Match the following processes with their descriptions:

    <p>Neurotransmitter release = Triggered by the influx of Ca2+ Enzyme degradation = Breaks down excess neurotransmitters Reuptake = Recaptures neurotransmitters for reuse Diffusion = Moves neurotransmitters away from synaptic cleft</p> Signup and view all the answers

    What occurs during depolarization of the membrane potential?

    <p>Increase in Na+ permeability</p> Signup and view all the answers

    The all-or-none principle states that action potentials can vary in amplitude based on the degree of depolarization.

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

    What happens to the membrane potential during repolarization?

    <p>The membrane potential returns from +30mV back to -70mV.</p> Signup and view all the answers

    After-hyperpolarization occurs when the permeability of K+ remains high for a period of _____ seconds.

    <p>5-15</p> Signup and view all the answers

    Match the stages of an action potential with their characteristics:

    <p>Depolarization = Membrane potential changes from -70mV to +30mV Repolarization = Membrane potential returns to -70mV After-hyperpolarization = Permeability of K+ remains high briefly Threshold = The point at which voltage-gated channels open</p> Signup and view all the answers

    What role do astrocytes play in the nervous system?

    <p>They provide metabolic support to neurons.</p> Signup and view all the answers

    Microglia are responsible for forming the myelin sheath in the CNS.

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

    Which cells provide myelination in the peripheral nervous system (PNS)?

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

    ____ cells provide metabolic support to neurons and help maintain the blood-brain barrier.

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

    Match the type of glial cell to their function:

    <p>Astrocytes = Regulate the external chemical environment of neurons Microglia = Immune defense in the CNS Oligodendrocytes = Form myelin sheath in the CNS Schwann cells = Form myelin sheath in the PNS</p> Signup and view all the answers

    What do Schwann cells form around an axon in the PNS?

    <p>Myelin sheath</p> Signup and view all the answers

    Unmyelinated axons have nodes of Ranvier.

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

    What is the primary function of the axon in a neuron?

    <p>Send information</p> Signup and view all the answers

    What primarily affects the conduction velocities of nerve fibers?

    <p>Diameter of the nerves and presence of myelin</p> Signup and view all the answers

    Myelinated nerves with the smallest diameter have the highest conduction velocities.

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

    Name a neurotoxin that blocks voltage-gated Na+ channels.

    <p>Tetrodotoxin (TTX)</p> Signup and view all the answers

    Neurotoxins interfere with the normal function of the __________ system.

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

    Match the following neurotoxins with their sources:

    <p>Tetrodotoxin (TTX) = Blowfish/Puffer fish Saxitoxin (STX) = Marine dinoflagellate Freshwater cyanobacterium = Cyanobacterium</p> Signup and view all the answers

    Which neurotoxin is toxic at nanomolar concentrations?

    <p>Both A and B</p> Signup and view all the answers

    Presence of myelin decreases nerve conduction velocities.

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

    What are the factors that determine conduction velocities of nerve fibers?

    <p>Diameter of the nerves and presence of myelin</p> Signup and view all the answers

    What is the function of serotonin in relation to mental health?

    <p>Involved in mood regulation and depression</p> Signup and view all the answers

    The transmission of action potentials in axons can occur in both directions.

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

    What neurotransmitter is commonly targeted by benzodiazepines to reduce anxiety?

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

    Morphine is used primarily as a __________.

    <p>pain killer</p> Signup and view all the answers

    Match the following neurotransmitters with their effects:

    <p>Glutamate = Excitatory neuron Serotonin = Depression Zolpidem = Sleeping aid Alcohol = Enhances action of GABA</p> Signup and view all the answers

    Why do myelinated axons conduct action potentials faster than unmyelinated axons?

    <p>They facilitate saltatory conduction.</p> Signup and view all the answers

    Anions have a higher concentration outside the cell compared to inside, resulting in a positive equilibrium potential.

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

    What is the primary anatomical organization of neurons that contribute to behavioral activity called?

    <p>Neural circuits</p> Signup and view all the answers

    Signup and view all the answers

    Study Notes

    Nervous System Physiology

    • The nervous system is divided into central nervous system (CNS) and peripheral nervous system (PNS).
    • The CNS includes the brain and spinal cord.
    • The PNS contains nerve fibers and ganglia.
    • Sensory (afferent) pathways transmit information toward the CNS.
    • Motor (efferent) pathways transmit information away from the CNS.
    • Somatic nervous system controls voluntary movements.
    • Autonomic nervous system controls involuntary functions (e.g., heart rate, digestion).
    • Sympathetic and parasympathetic systems are parts of the autonomic nervous system.

    Neuron Structure and Function

    • Neurons are the basic units of the nervous system.
    • Neurons have cell bodies (soma), dendrites, and axons.
    • Dendrites receive signals.
    • Axons transmit signals.
    • Synapses are junctions between neurons.
    • Glial cells support and protect neurons.

    Neuron Electrical Properties

    • Resting membrane potential is the electrical potential across a neuron at rest (-70mV).
    • Action potentials are rapid, large changes in membrane potential that transmit signals.
    • Action potential arise from changes in permeability of the membrane to ions.
    • There are 3 phases: rising, falling and recovery, in action potential.
    • Concentration gradients across the membrane, specific ion channels, and their permeability to ions are key to creating the resting potential.

    Nerve Impulse Transmission

    • Myelinated axons transmit signals faster than unmyelinated axons.
    • The myelin sheath insulates the axon, increasing the speed of signal transmission.
    • In unmyelinated axons, the signal propagates continuously.
    • In myelinated axons, the signal jumps between nodes of Ranvier—a phenomenon called saltatory conduction.

    Synaptic Transmission

    • Synapses are junctions between neurons.
    • Chemical synapses use neurotransmitters to transmit signals.
    • Electrical synapses transmit signals directly through gap junctions.
    • Neurotransmitters bind to receptors on the postsynaptic neuron, causing either an excitatory (depolarizing) or inhibitory (hyperpolarizing) postsynaptic potential (PSP).

    Neurotransmitters

    • Neurotransmitters are chemical messengers that transmit signals across synapses.
    • Examples of neurotransmitters include acetylcholine, glutamate, GABA, and others.
    • Neurotransmitters can have varied effects depending upon the receptor they bind.
    • Neurotransmitters are categorized into various classes including amino acids, biogenic amines, peptides, etc.

    Neural Integration

    • Neural circuits are networks of interconnected neurons that process information.
    • Divergent pathways allow one presynaptic neuron to influence multiple postsynaptic neurons.
    • Convergent pathways allow multiple presynaptic neurons to influence a single postsynaptic neuron.
    • Summation refers to the combining of graded potentials in relation to thresholding.

    Types of Synapses

    • Electrical synapses pass signals very quickly directly through gap junctions.
    • Chemical synapses use neurotransmitters that bind to receptors, triggering post-synaptic potentials (PSPs)
    • Types of chemical synapses include ionotropic (fast) and metabotropic (slow) chemical synapses
    • Neurotransmitter receptors can be either ionotropic or metabotropic.

    Neuronal Classifications

    • Based on function, neurons can be categorized as sensory (afferent), motor (efferent), or interneurons.
    • Based on structure, neurons are categorized as unipolar, bipolar, and multipolar.
    • The differences in structure dictate their function and actions within the nervous system to aid in efficient cellular communication and response.

    Glial Cells

    • Supporting cells in the CNS.
    • Glial cells (70-90% of the CNS cells) perform various functions: structural support, metabolic support, forming blood-brain-barrier and myelin sheath, removal of dead neurons.
    • Different types of glial cells with different functions; Astrocytes, oligodendrocytes (CNS), schwann cells (PNS), microglia, ependymal cells.

    Neurotoxins

    • Neurotoxins are substances that interfere with the normal function of the nervous system, often impacting ion channels.

    Key Definitions

    • Action Potential: A rapid, large change in membrane potential that propagates along an axon.
    • Graded Potential: A small, local change in membrane potential in response to a stimulus that does not necessarily propagate down the entire axon.
    • Postsynaptic Potential: A change in the membrane potential of a postsynaptic neuron in response to neurotransmitters binding to receptors.
    • Refractory Period: The period of time after an action potential during which the neuron cannot generate another action potential (absolute) or will only generate it with stronger stimuli (relative).
    • EPSP: Excitatory postsynaptic potential (causes depolarization)
    • IPSP: Inhibitory postsynaptic potential (causes hyperpolarization).
    • Threshold Potential: The membrane potential at which an action potential is generated.

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    Nervous System I PDF

    Description

    Test your knowledge on the nervous system with this quiz covering involuntary actions, neurotransmitter functions, and neural communication processes. Questions include matching brain structures with their functions, understanding postsynaptic potentials, and the impact of myelination on nerve impulses.

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