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Multiple Choice Questions - mcqs -Neurons

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mcqs -Neurons

multiple-choice-questions-on-neurons

Neurons

Neurons generate and propagate nerve impulses. Some parts of the neurons receive signals from other neurons whereas some other parts propagate these impulses to other neurons.

mcqs -Neurons

Action Potential

The action potential arise from a region that resembles a mound on one side of the cell body in a neuron.

Action potentials are transmitted rapidly by the successive activation of regions that extends from the cell body to the axon terminals.

Neurotransmitters

Neurotransmitters are chemicals which help in the transmission of impulses from a neuron to a cell across the synapse.

They participate in electro-chemical communication from one nerve cell to another or one nerve cell to various organs in the body.

mcqs -Neurons

Neuron as the Basic Functioning Unit

Nervous system is the fast communication system in the body. It is organised into central nervous system and the peripheral nervous system. The functioning unit of the nervous system is the nerve cell or neuron.

Schwann Cells

Schwann cells are glial cells that wrap around the nerve fiber in the peripheral nervous system


Saltatory Conduction

The myelin sheath is fatty and consists of layers of lipids, including cholesterol and phospholipids, separated by thin layers of protein. There are periodic gaps in the myelin sheath on the axon of certain neurons that serves to facilitate the rapid conduction of nerve impulses. Impulses to jump from this gap to gap in a process known as saltatory conduction


Sodium-Potassium Pump

Sodium-potassium pump is a protein found in many cells that maintains the concentration of potassium ions [K+] and sodium ions [Na+]. The most abundant intracellular ion is potassium and the most abundant extracellular ion is sodium. The pump is activated by external concentration of [K+] and internal concentration of [Na+].


Graded Potentials

Graded potentials result from the changes in the membrane potential caused by movement of ions across the cell membrane.

Graded potential may be excitatory or inhibitory and do not behave like action potentials. Graded potential decay over short distances from the point of initiation and depending upon the type of ion channel involved, it may excite or inhibit a neuron. Action potentials are the fully developed nerve impulses generated at the axon hillock and travel through the entire length of axons.


Multiple Choice Questions (mcqs) on Neurons

For each question, choose the best answer. The answer key is below.

  1. Which portion of the neuron acts as the “conducting zone” for transmitting impulses?
    • Axon
    • Cell body
    • Dendrites
    • Nucleus
  2. Which parts of the neuron receives impulses from other cells or sensory structures?
    • Axon or Cell body
    • Cell body or Dendrites
    • Dendrites or Nucleus
    • Nucleus or Axon
  3. The portion of the neuron which acts as a “trigger zone” ...
    • Axon hillock
    • Axon terminals
    • Cell body
    • Dendrites
  4. Which portion of the neuron release chemical neurotransmitters?
    • Axon hillock
    • Axon terminals
    • Cell body
    • Dendrites
  5. The portion of the neuron containing the nucleus and major organelles and is also known as “soma” is
    • Axon hillock
    • Axon terminals
    • Cell body
    • Dendrites
  6. Which part of the neuron has Schwann cells associated with it?
    • Axon
    • Cell body
    • Dendrites
    • Nucleus
  7. Which part contributes to rapid transmission of action potentials on a peripheral neuron?
    • Axon
    • Axon hillock
    • Nodes of Ranvier
    • Dendrites
  8. The area between the Schwann cells where the axon is bare and in direct contact with the extracellular fluid is
    • Axon
    • Axon hillock
    • Nodes of Ranvier
    • Dendrites
  9. Which ion crosses the neuron membrane through open gated ion channels to initiate a graded potential?
    • Na+
    • K+
    • Cl-
    • Ca2+
  10. Graded potentials occur on the membrane of
    • Dendrites and Soma
    • Soma and Nucleus
    • Nucleus and Axon hillock
    • Axon Hillock and axon terminals

Answer Key

  1. Axon
  2. Cell body or Dendrites
  3. Axon hillock
  4. Axon terminals
  5. Cell body
  6. Axon
  7. Nodes of Ranvier
  8. Nodes of Ranvier
  9. Na+
  10. Dendrites and Soma

Refractory period is the minimum period of time required for the same area of axon membrane to generate a second action potential


The depolarisation beginning at the axon hillock spreads sequentially to the nodes of Ranvier “downstream” from the hillock


Myelin sheath influences the transmission of impulses. Without myelin the entire surface of axon membrane has to sequentially depolarise and repolarise needing more time.The fastest transmission of action potential occur with large diameter myelinated axons.

Neurons communicate with other cells by way of synapses. Synapses are special sites where a presynaptic neuron releases neurotransmitters which will get attached to receptors in the postsynaptic neuron. Neurons extend terminals to many other celss and receive input from other neurons which will form nerve pathways.


Multiple Choice Questions (mcqs) on Neurons

For each question, choose the best answer. The answer key is below.

  1. Which of the following statement is true with regard to graded potential?
    • Graded potential cannot depolarise or hyperpolarise
    • Graded potentials are proportional to the stimulus strength
    • Graded potential is an “all or none” response
    • Graded potentials have a refractory period
  2. Which part of the action potential is produced by the rapid influx of sodium?
    • Depolarisation
    • Repolarisation
    • Hyperpolarisation
    • After-hyperpolarisation
  3. During which part of action potential, the slow voltage gated K + channels close and the Na+ K+ ATPase pump fully restor
    • Depolarisation
    • Repolarisation
    • Hyperpolarisation
    • After-hyperpolarisation
  4. The absolute refractory period is due to
    • High number of sodium channels that have their inactivation gate closed
    • High number of closed potassium channels
    • Rapid Ca2+ influx at axon hillock
    • Shutdown of Na+ K+ ATPase pump
  5. Which physiological mechanism is responsible for one way propagation of action potential?
    • “All or none” law
    • Na+ K+ ATPase pump
    • Absolute refractory period
    • Ca2+ influx at axon hillock
  6. An insulating lipid elaborated by oligodendrocytes centrally or Schwann cells peripherally that surrounds the axons
    • Myelin
    • Neurofilament
    • Connexin
    • Striatum
  7. Which part of the synapse is depolarised by an action potential to trigger the subsequent events of synaptic transmissio
    • Synaptic vesicles
    • Synaptic cleft
    • Presynaptic cell terminal
    • Post synaptic cell
  8. Which is the storage site for neurotransmitter before release?
    • Presynaptic cell terminal
    • Synaptic vesicles
    • Synaptic cleft
    • Post synaptic cell
  9. Which part of the synapse is known as the synaptic gap or gutter?
    • Presynaptic cell terminal
    • Synaptic vesicles
    • Synaptic cleft
    • Post synaptic cell
  10. The neurotransmitter molecules cross the synaptic cleft by
    • Osmosis
    • Active transport
    • Passive diffusion
    • Secondary active transport

Answer Key

  1. Graded potentials are proportional to the stimulus strength
  2. Depolarisation
  3. After-hyperpolarisation
  4. High number of sodium channels that have their inactivation gate closed
  5. Absolute refractory period
  6. Myelin
  7. Presynaptic cell terminal
  8. Synaptic vesicles
  9. Synaptic cleft
  10. Passive diffusion

Comments

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