Tag: structure and function of neuron

Questions Related to structure and function of neuron

End plate junction is present between

biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

  1. Neuron and striated muscle

  2. Neuron and neuron

  3. Muscle and muscle

  4. Both (b) and (c)

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Correct Option: A
Explanation:
  • The site of chemical communication between a nerve fibre and a muscle cell is called the end plate junction or neuromuscular junction.
  • The neuromuscular junction is analogous to the synapse between two neurons. 
  • A nerve fibre divides into many terminal branches; each terminal ends on a region of muscle fibre called the end plate. Embedded in the end plate are thousands of receptors. 
  • So, the correct option is 'Neuron and Striated muscle'.

The myelin sheath around the axon is produced by which type of neurogical cells?

biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

  1. Satellite glial cells

  2. Radial glial cells

  3. Dendrocytes

  4. Schwann cells

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Correct Option: D
Explanation:


  1. Myelin sheath is formed by oligodendrocytes in the central nervous system and by Schwann cells in the peripheral nervous system. 
  2. These cells wrap layer upon layer of their own plasma membrane in a tight spiral around axon. 
  3. The insulating layer checks the leakage of charge and lesser stoppage points (nodes of Ranvier) leading to acceleration of the conduction and conservation of the metabolic energy.
So, the correct option is 'Schwann cells'.

During depolarisation of neuron

biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

  1. $K^+$ channels remain open

  2. N$a^+$ gets inside through ion channels

  3. N$a^+$ gets outside through ion channels

  4. All the above

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Correct Option: B

An investigator places an isolated neuron in a calcium-free medium, gives the neuron a suprathreshold stimulus and then performs an assay to test whether neurotransmitter is released into the medium. Which of the following outcomes would you predict?

biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

  1. No neurotransmitter is detected since influx of calcium into the synaptic knob is required for neurotransmitter release.

  2. No neurotransmitter is detected since influx of calcium is required in order for the neuron to conduct an action potential.

  3. Neurotransmitter is detected since calcium is not required for action potential conduction and the initial stimulus was suprathreshold.

  4. We cannot predict the outcome without knowing whether the neuron was myelinated or non-myelinated.

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Correct Option: A

Choose the correct answer from the alternatives given.
Grey matter is

biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

  1. located on the outside of the spinal cord

  2. restricted to the brain

  3. populated by cell bodies of neurons

  4. found in the ventricles of the vertebrate brain

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Correct Option: C
Explanation:

Grey matter is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil, glial cells, synapses, and capillaries.

So, the correct option is 'populated by cell bodies of neurons'.

Synaptic vesicles are

biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

  1. at the ends of dendrites and axons

  2. at the ends of axons only

  3. along the length of all long fibres

  4. all of the above

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Correct Option: B
Explanation:

In a neuron, synaptic vesicles store various neurotransmitter that is released at the synapse. The release is regulated by a voltage-dependent calcium channel. Vesicles are essential for propagation nerve impulses between neurons and are constantly recreated by the cell.

So, the correct option is 'at the ends of axons only'.

Assertion : Myelinated nerve fibre are enveloped with Schwann cells, which form a myelin sheath around the axon
Reason : Unmyelinated nerve fibre is not enclosed by a Shwann cell and hence does not form a myelin sheath around the axon

biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

  1. If both assertion and reason are true and the reason is the correct explanation of the assertion

  2. If both assertion and reason are true but reason is not the correct explanation of the assertion

  3. If assertion is true but reason is false

  4. If both assertion and reason are false

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Correct Option: B
Explanation:

The myelinated nerve fibers contain a myelin sheath surrounding the axons of nerve cells. While in unmyelinated nerve fibre is not enclosed by a Schwann cell and hence does not form a myelin sheath around the axon.

So the correct option is "Both Assertion and Reason are correct but the reason is not the correct explanation of assertion".

The .................... of the neuron secretes the substance named neurotransmitter.

biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

  1. Axon

  2. Dendron

  3. Schwann cell

  4. None of the above

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Correct Option: A
Explanation:

The axon of the neuron secretes the substance named neurotransmitter to communicate with next dendrite.

Neurotransmitters are the brain chemicals that communicate information throughout our brain and body.

The role of the axon is to

biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

  1. Integrate signals from the dendrites

  2. Release neurotransmitter

  3. Conduct the impulse to the synaptic terminal

  4. Synthesize cellular components

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Correct Option: C
Explanation:
An axon also known as a nerve fibre, is a long, slender projection of a nerve cell, or neuron, that typically conducts electrical impulses away from the neuron's cell body. The function of the axon is to transmit information to different neurons, muscles and glands. The space between two neuron is known as synapse. The nerve impulse is transmitted towards the synaptic terminal from the dendron.

In comparison with other cells, nerve cells show a higher degree of

biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

  1. Metabolism

  2. Growth

  3. Contractility

  4. Irritability

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Correct Option: D
Explanation:

Irritability or excitability is the ability of nerve cells to respond to environmental stimulus. Primary function of nerve cells is to generate sensory input in response to external and internal stimuli followed by integration of sensory information to generate motor output. Thus, nerve cells exhibit higher rate of irritability as compared to other cell types. 

Therefore, the correct answer is option D.