Nervous System Overview
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Questions and Answers

What are the two main divisions of the nervous system?

  • Sympathetic nervous system and parasympathetic nervous system
  • Sensory nervous system and motor nervous system
  • Somatic nervous system and autonomic nervous system
  • Central nervous system and peripheral nervous system (correct)

    • The central nervous system (CNS) includes the brain and the spinal cord.

    True

    The peripheral nervous system (PNS) is made up of all nervous tissue outside the CNS.

    True

    What is the primary function of the sensory division of the nervous system?

    <p>The sensory division conducts action potentials from the sensory receptors to the CNS.</p> Signup and view all the answers

    Choose the correct statement about the somatic nervous system.

    <p>It transmits action potentials from the CNS to skeletal muscles.</p> Signup and view all the answers

    Which of the following is a function of the autonomic nervous system?

    <p>Regulation of heart rate and breathing</p> Signup and view all the answers

    Where is the enteric nervous system located?

    <p>Digestive tract</p> Signup and view all the answers

    What are the two types of cells found in the nervous system?

    <p>Neurons and glial cells.</p> Signup and view all the answers

    Neurons are supportive cells of the CNS and PNS.

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

    Glial cells conduct action potentials.

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

    What are the main components of a neuron?

    <p>A neuron consists of a cell body, dendrites, and an axon.</p> Signup and view all the answers

    The ______ is a cytoplasmic extension that receives information from other neurons.

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

    The ______ is a single long extension that transmits signals to other neurons or effector organs.

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

    What type of neuron has many dendrites and a single axon?

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

    Which type of neuron has two processes: one dendrite and one axon?

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

    What type of neuron has a single process that splits into two branches?

    <p>Pseudo-unipolar</p> Signup and view all the answers

    What are the four main types of glial cells in the CNS?

    <p>The four main types of glial cells in the CNS are astrocytes, ependymal cells, microglial cells, and oligodendrocytes.</p> Signup and view all the answers

    What is the primary function of Schwann cells?

    <p>Schwann cells provide myelin to neurons in the PNS.</p> Signup and view all the answers

    Which type of glial cell forms the blood-brain barrier?

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

    What is the primary function of myelin sheaths?

    <p>Myelin sheaths are specialized layers that wrap around the axons of some neurons, providing insulation and increasing the speed of nerve impulse transmission.</p> Signup and view all the answers

    Myelinated axons conduct nerve impulses faster than unmyelinated axons.

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

    What is the process of nerve impulse transmission along myelinated axons called?

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

    What type of membrane channels are always open?

    <p>Leak channels</p> Signup and view all the answers

    Which type of membrane channels are closed until opened by specific signals?

    <p>Gated channels</p> Signup and view all the answers

    Which of these is NOT a type of gated channel?

    <p>Leak channels</p> Signup and view all the answers

    What is the function of the sodium-potassium pump?

    <p>The sodium-potassium pump actively transports potassium ions (K+) into the cell and sodium ions (Na+) out of the cell, helping maintain the concentration gradients necessary for resting membrane potential and action potential generation.</p> Signup and view all the answers

    The resting membrane potential is a result of a higher concentration of sodium ions (Na+) inside the cell and a higher concentration of potassium ions (K+) outside the cell.

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

    The sodium-potassium pump is responsible for the movement of Na+ into the cell and K+ out of the cell.

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

    Action potentials are generated by the movement of ions across the cell membrane.

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

    What is the term for the process by which the inside of the cell membrane becomes more positive?

    <p>Depolarization.</p> Signup and view all the answers

    What term describes the process of the cell membrane returning to its resting potential after depolarization?

    <p>Repolarization.</p> Signup and view all the answers

    Action potentials can occur in a graded fashion, meaning their magnitude can vary.

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

    What is the term for the junction between two neurons?

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

    Neurotransmitters are released from the presynaptic neuron.

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

    What is the name of the enzyme that breaks down acetylcholine?

    <p>Acetylcholinesterase.</p> Signup and view all the answers

    What are the two major neurotransmitters?

    <p>The two major neurotransmitters are acetylcholine and norepinephrine.</p> Signup and view all the answers

    The effects of neurotransmitters are long-lasting.

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

    What type of neuronal pathway involves two or more neurons converging onto a single postsynaptic neuron?

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

    What type of neuronal pathway involves a single presynaptic neuron sending signals to multiple postsynaptic neurons?

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

    A reflex arc is a neuronal pathway responsible for involuntary responses.

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

    What are the five components of a reflex arc?

    <p>The five components of a reflex arc are a sensory receptor, a sensory neuron, interneurons, a motor neuron, and an effector organ.</p> Signup and view all the answers

    Simple reflex arcs do not involve interneurons.

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

    What is the term for the process by which multiple presynaptic action potentials combine their effects on a postsynaptic neuron?

    <p>Summation.</p> Signup and view all the answers

    Which type of summation occurs when local potentials originate from different locations on the postsynaptic neuron?

    <p>Spatial summation</p> Signup and view all the answers

    Which type of summation occurs when local potentials are generated close together in time?

    <p>Temporal summation</p> Signup and view all the answers

    The peripheral nervous system is made up of all of the nervous tissue outside of the CNS.

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

    What is the name given to the junction where the axon of one neuron interacts with another neuron?

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

    What are the specialized layers that wrap around the axons of some neurons called?

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

    What is the name of the process by which myelination of an axon increases the speed and efficiency of action potential generation along the axon?

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

    What is the name of the process that describes the integration of multiple subthreshold local potentials?

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

    What are the two types of summation?

    <p>Spatial and Temporal Summation</p> Signup and view all the answers

    Which of these is NOT a type of neuron?

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

    What are the four types of glial cells in the central nervous system (CNS)?

    <p>Astrocytes, Ependymal cells, Microglial cells, and Oligodendrocytes</p> Signup and view all the answers

    What type of glial cells are known for providing myelin to neurons?

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

    What is the type of ion that is largely found found inside of the cell membrane?

    <p>Potassium (K$^{+}$)</p> Signup and view all the answers

    The ______ is a junction between two neurons and is responsible for transmitting messages from one neuron to another.

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

    Neurons are specialized cells that generate and transmit electrical signals for fast communication in the nervous system.

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

    What is the name of the chemical substances stored in synaptic vesicles that are released across the synaptic cleft to transmit signals between neurons?

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

    Which of the following is NOT a true statement about the sodium-potassium pump?

    <p>It is responsible for the rapid propagation of action potentials along an axon.</p> Signup and view all the answers

    The resting membrane potential is a state where the inside of a neuron is more positively charged than the outside.

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

    What is the name of the change in membrane potential that occurs when the inside of a neuron becomes more positive due to an influx of sodium (Na$^{+}$) ions?

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

    What is the name of the change in membrane potential that occurs when the inside of a neuron becomes more negative than the resting membrane potential?

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

    Which of the following is NOT a characteristic of an action potential?

    <p>It can be graded, meaning its amplitude can vary depending on the strength of the stimulus.</p> Signup and view all the answers

    A reflex arc is the neuronal pathway by which a reflex occurs.

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

    Which of the following is NOT a component of a reflex arc?

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

    What are the two main types of neuronal pathways?

    <p>Converging and Diverging</p> Signup and view all the answers

    A converging pathway is a simple pathway in which an axon from one neuron divides and synapses with more than one other postsynaptic neuron.

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

    Study Notes

    Nervous System Divisions

    • The central nervous system (CNS) comprises the brain and spinal cord, acting as the control center.
    • The peripheral nervous system (PNS) encompasses all nervous tissue outside the CNS, responsible for communication between the CNS and the rest of the body.

    Nervous System Functions

    • The sensory division of the PNS transmits information from sensory receptors to the CNS, providing awareness about internal and external environments.
    • The somatic nervous system, a part of the PNS, controls voluntary movements of skeletal muscles.
    • The autonomic nervous system (ANS) regulates involuntary bodily functions like heart rate, digestion, and breathing.
    • The enteric nervous system is embedded within the walls of the digestive tract, controlling its functions independently of the CNS.

    Nervous System Cells

    • The nervous system consists of two main cell types: neurons and glial cells.
    • Neurons are the functional units of the nervous system, transmitting nerve impulses.
    • Glial cells support and protect neurons, playing crucial roles in maintaining the environment and assisting in the transmission of signals.

    Neuron Structure

    • Neurons possess three main components:
      • Dendrites: Branching extensions that receive information from other neurons.
      • Cell body (soma): Contains the nucleus and other organelles.
      • Axon: A single, long extension that transmits signals to other neurons or effector organs.

    Neuron Types

    • Multipolar neurons have multiple dendrites and a single axon, the most common type.
    • Bipolar neurons have two processes: one dendrite and one axon.
    • Unipolar neurons have a single process that splits into two branches, one functioning as a dendrite and the other as an axon.

    Glial Cells in CNS

    • The four main types of glial cells in the CNS are:
      • Astrocytes: Star-shaped cells that support neurons, maintain the blood-brain barrier, and regulate the extracellular environment.
      • Oligodendrocytes: Form myelin sheaths around axons in the CNS, facilitating fast signal transmission.
      • Microglia: Act as immune cells, removing debris and protecting the CNS from pathogens.
      • Ependymal cells: Line the ventricles of the brain and spinal cord, producing cerebrospinal fluid.

    Myelin Sheath

    • Schwann cells, glial cells in the PNS, form myelin sheaths around axons.
    • Myelin sheaths are lipid-rich coverings that insulate axons, increasing the speed of nerve impulse transmission.
    • Saltatory conduction is the process of nerve impulse transmission along myelinated axons, where the impulse jumps from one node of Ranvier to the next, increasing efficiency.

    Membrane Channels

    • Leak channels are always open, allowing the passive diffusion of ions across the cell membrane.
    • Gated channels are closed until opened by specific signals, controlling the movement of ions.
    • Voltage-gated channels open or close in response to changes in membrane potential.
    • Ligand-gated channels open or close when a specific molecule binds to them.
    • Mechanically gated channels are activated by physical deformation of the cell membrane.

    Sodium-Potassium Pump

    • The sodium-potassium pump actively transports sodium ions out of the cell and potassium ions into the cell, maintaining the concentration gradients necessary for nerve impulse transmission.

    Resting Membrane Potential

    • The resting membrane potential is the electrical potential difference across the cell membrane when the neuron is not transmitting a signal.
    • The resting membrane potential is maintained by the sodium-potassium pump and the permeability of the cell membrane to different ions.

    Action Potential

    • Action potentials are rapid changes in membrane potential that travel along the axon, transmitting nerve impulses.
    • Depolarization is the process of the inside of the cell becoming more positive.
    • Repolarization is the process of the cell membrane returning to its resting potential after depolarization.
    • Action potentials are all-or-none events, meaning they either occur fully or not at all.

    Synapse

    • A synapse is the junction between two neurons where nerve impulses are transmitted.
    • Neurotransmitters are chemical messengers released from the presynaptic neuron that bind to receptors on the postsynaptic neuron, initiating a signal.

    Neurotransmitters

    • Acetylcholine (ACh) is a major neurotransmitter in the nervous system, involved in muscle contraction, memory, and learning.
    • Acetylcholinesterase is the enzyme that breaks down acetylcholine.
    • Other significant neurotransmitters include dopamine, serotonin, norepinephrine, and GABA.

    Neuronal Pathways

    • Convergent pathways involve two or more neurons converging onto a single postsynaptic neuron, integrating multiple inputs.
    • Divergent pathways involve a single presynaptic neuron sending signals to multiple postsynaptic neurons, amplifying the signal.

    Reflex Arc

    • A reflex arc is a neuronal pathway that controls involuntary responses to stimuli, bypassing the conscious brain.
    • The five components of a reflex arc are:
      • Receptor: Detects the stimulus.
      • Sensory neuron: Transmits the signal to the CNS.
      • Integration center: Processes the information.
      • Motor neuron: Transmits the signal to the effector.
      • Effector: Carries out the response.

    Summation

    • Summation is the process of adding together the effects of multiple local potentials on a postsynaptic neuron.
    • Spatial summation occurs when local potentials originate from different locations on the postsynaptic neuron.
    • Temporal summation occurs when local potentials are generated close together in time.

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    Description

    Explore the intricate functions and divisions of the nervous system in this quiz. Learn about the roles of the Central and Peripheral Nervous Systems, along with their subdivisions. Test your knowledge on sensory and motor pathways, and how they contribute to bodily functions.

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