Neuroscience Quiz: Action Potentials and Neurons
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Questions and Answers

What is the primary ion responsible for depolarization during the action potential?

  • Sodium ($ ext{Na}^{+}$) (correct)
  • Potassium ($ ext{K}^{+}$)
  • Calcium ($ ext{Ca}^{2+}$)
  • Chloride ($ ext{Cl}^{-}$)

    • The resting membrane potential is approximately +30 mV.

    False

    What do you call the phase when the membrane potential decreases back toward resting potential?

    Repolarization

    The minimum membrane potential needed to trigger an action potential is called the _______.

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

    Match the following phases of the action potential with their descriptions:

    <p>Depolarization = Increase in membrane potential towards +30 mV Repolarization = Decrease in membrane potential back to resting level After-hyperpolarization = Dip below resting potential Absolute Refractory Period = Inability to generate another action potential</p> Signup and view all the answers

    What is the primary function of interneurons in the Central Nervous System?

    <p>Integration and processing of information</p> Signup and view all the answers

    Motor neurons conduct signals from the CNS to sensory receptors.

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

    What component of the neuron receives signals from other neurons?

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

    Signals travel from sensory receptors to the CNS via __________ neurons.

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

    Match the following neuron types with their functions:

    <p>Sensory Neurons = Conduct signals from sensory receptors to the CNS Motor Neurons = Transmit signals from the CNS to muscles Interneurons = Integrate and process information Ganglion = Cluster of nerve cell bodies</p> Signup and view all the answers

    What is the role of receptors in the nervous system?

    <p>To detect stimuli</p> Signup and view all the answers

    The endocrine system is not involved in maintaining homeostasis.

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

    What are the two major systems for coordination and control in animals?

    <p>Nervous system and endocrine system</p> Signup and view all the answers

    The complex communication network of the nervous system is formed by _______.

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

    Match the types of neurons with their functions:

    <p>Sensory neurons = Transmit signals to the CNS Intermediate neurons = Process information within the CNS Motor neurons = Carry signals to effectors</p> Signup and view all the answers

    Which component of the human nervous system is responsible for interpreting information?

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

    The spinal cord connects the Central Nervous System to the Peripheral Nervous System.

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

    Name the three types of neurons mentioned.

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

    What is the main function of synapses in the nervous system?

    <p>To transmit nerve impulses</p> Signup and view all the answers

    Synapses allow for direct physical contact between neurons.

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

    What is the gap between the presynaptic and postsynaptic membranes called?

    <p>synaptic cleft</p> Signup and view all the answers

    Neurotransmitters are released from synaptic _____ to transmit signals across the synaptic cleft.

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

    Match the following components of a synapse with their functions:

    <p>Axon = Long projection that transmits impulses Synaptic Vesicles = Contain neurotransmitters Dendrites = Receive signals from other neurons Neurotransmitter Substance = Chemicals that transmit signals across the synaptic cleft</p> Signup and view all the answers

    How many synapses can a single motor neuron in the spinal cord have?

    <p>Over 1000</p> Signup and view all the answers

    Mitochondria provide energy for neurotransmission.

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

    The _____ neuron is the one that releases neurotransmitters at the synapse.

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

    What is the primary function of neurotransmitters?

    <p>To transmit nerve impulses across the synapse</p> Signup and view all the answers

    Cholinergic neurons release norepinephrine.

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

    What separates the presynaptic and postsynaptic membranes?

    <p>synaptic cleft</p> Signup and view all the answers

    The membrane of the synaptic knob closest to the synapse is called the ______.

    <p>presynaptic membrane</p> Signup and view all the answers

    Which neurotransmitter is associated with the sympathetic nervous system?

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

    Match the neurotransmitter with its corresponding neuron type:

    <p>Acetylcholine = Cholinergic neurons Norepinephrine = Adrenergic neurons</p> Signup and view all the answers

    Neuroreceptors are located on the presynaptic membrane.

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

    Neurotransmitters are stored in small ______ within the synaptic knob.

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

    Which portion of the Peripheral Nervous System carries sensory information to the CNS?

    <p>Afferent portion</p> Signup and view all the answers

    The efferent portion of the PNS only carries information related to involuntary functions.

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

    What is the role of interneurons within the CNS?

    <p>To process information</p> Signup and view all the answers

    The brain and spinal cord are part of the _____ Nervous System.

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

    Which of the following statements is true regarding sensory receptors?

    <p>They receive stimuli from the environment.</p> Signup and view all the answers

    Match the nervous system components with their functions:

    <p>Sensory Receptor = Receives stimuli from the environment Sensory Neurons = Transmit signals to the CNS Motor Neurons = Transmit signals from the CNS Interneurons = Process information within the CNS</p> Signup and view all the answers

    What is the primary function of neurohormones?

    <p>To affect other organs through the circulatory system</p> Signup and view all the answers

    Name one hormone that is stored in the posterior pituitary.

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

    What is the typical resting potential of neurons in humans?

    <p>-70 mV</p> Signup and view all the answers

    The resting potential of a neuron is the potential difference across the membrane of a stimulated neuron.

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

    What active transport mechanism is primarily responsible for maintaining the resting potential in neurons?

    <p>Na-K pump</p> Signup and view all the answers

    The cytoplasm of the nerve fiber has a high concentration of _____ ions.

    <p>potassium (K⁺)</p> Signup and view all the answers

    Match the following ions with their location during the resting potential.

    <p>K⁺ = High concentration inside the cell Na⁺ = High concentration outside the cell</p> Signup and view all the answers

    What effect does the permeability of the membrane have on resting potential?

    <p>Affects the rate of ion diffusion</p> Signup and view all the answers

    In the resting membrane, most Na⁺ channels are open.

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

    What ion tends to diffuse out of the cell, leading to a net negative charge inside the nerve fiber?

    <p>potassium (K⁺)</p> Signup and view all the answers

    What initiates the release of neurotransmitters from the synaptic vesicles?

    <p>Influx of calcium ions ($Ca^{2+}$)</p> Signup and view all the answers

    Acetylcholine attaches to any type of receptor on the postsynaptic membrane.

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

    What is the approximate delay caused by the diffusion of acetylcholine across the synaptic cleft?

    <p>0.5 ms</p> Signup and view all the answers

    The process of synaptic transmission involves the release of a neurotransmitter called __________.

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

    What is the duration of the refractory period?

    <p>2 milliseconds</p> Signup and view all the answers

    Match the components of synaptic transmission with their roles:

    <p>Calcium ions ($Ca^{2+}$) = Trigger vesicle fusion Acetylcholine = Neurotransmitter released Sodium ions ($Na^+$) = Generate action potential Neuroreceptor = Recognizes neurotransmitter</p> Signup and view all the answers

    The refractory period allows for multiple action potentials to occur simultaneously.

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

    What are the two phases of the refractory period?

    <p>Absolute refractory period and Relative refractory period</p> Signup and view all the answers

    The ______ refractory period does not allow any additional action potential to be generated no matter the strength of the stimulus.

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

    What function does the refractory period serve regarding conduction?

    <p>It ensures unidirectional conduction.</p> Signup and view all the answers

    Match the following terms with their descriptions:

    <p>Resting potential = State of the membrane before an action potential Active region = Part involved in generating the action potential Inactive region = Area just preparing to generate another action potential Trigger zone = Location where the action potential begins</p> Signup and view all the answers

    The Na-K pump restores the resting concentrations of Na+ and K+ during the ______ period.

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

    During the relative refractory period, a second action potential can occur but requires a stronger stimulus.

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

    What happens during the depolarization phase of the action potential?

    <p>Sodium gates open and sodium floods into the cell</p> Signup and view all the answers

    During repolarization, potassium continues to outflow while sodium permeability declines.

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

    What is hyperpolarization?

    <p>A phase where the membrane potential becomes more negative than the resting potential.</p> Signup and view all the answers

    The _____ pump is responsible for restoring the normal resting potential of the nerve fibre.

    <p>Na-K</p> Signup and view all the answers

    Match the phase of the action potential with the related event:

    <p>Depolarization = Sodium gates open Repolarization = Potassium outflow Hyperpolarization = Overshoot of negativity Resting Potential = Na-K pump activity</p> Signup and view all the answers

    What initiates repolarization in a nerve fibre?

    <p>The closing of sodium gates</p> Signup and view all the answers

    All sodium channels close before potassium channels open.

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

    How does the membrane potential change during an action potential?

    <p>It becomes positive during depolarization, then returns to negative during repolarization and hyperpolarization.</p> Signup and view all the answers

    Study Notes

    The Nervous System

    • The nervous system is responsible for coordinating and controlling physiological activities and transmitting information
    • The nervous system works with the endocrine system to maintain homeostasis
    • The hypothalamus is a significant link between the nervous and endocrine systems
    • The nervous system utilises electrical impulses and chemical messengers for communication
    • The nervous system involves three major components: the brain, the spinal cord, and nerves to all parts of the body
    • Two major divisions of the nervous system:
      • Central Nervous System (CNS): the brain and spinal cord. It is the control center for the body.
      • Peripheral Nervous System (PNS): A network of nerves that connects the CNS to other parts of the body. It carries information to and from the CNS
    • Different nerves
      • Sensory nerves bring sensory information to the CNS
      • Motor nerves carry information from the CNS and trigger responses
    • Sensory neurons: responsible for carrying information from sensory organs (eyes, ears, skin, joints, and skeletal muscle) to the CNS
    • Motor neurons: responsible for carrying information from the CNS to effectors (muscles and glands)
    • There are two types of motor neurons: conscious and unconscious.
    • Conscious pathways control voluntary movements, while unconscious ones regulate involuntary actions.
    • Interneurons: located entirely within the CNS, these neurons connect sensory and motor neurons, processing information and transmitting signals between them
    • Neurohormones: some neurons produce neurohormones which are hormones delivered through the circulatory system. The neurohormones act on other organs to regulate their function — including controlling the function of the pituitary gland
    • High levels of hormones will trigger the hypothalamus and the pituitary gland to stop their release

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    Description

    Test your knowledge on the action potential phases, neuron types, and their functions within the nervous system. This quiz covers key concepts like depolarization, membrane potential, and the roles of different neurons. Perfect for students studying neuroscience or biology.

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