Tag: structure of neuron

Questions Related to structure of neuron

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

Show answer
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

Show answer
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

Show answer
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

Show answer
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

Show answer
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

Show answer
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.

Statements (A, B, C, D) in List I have to be matched with statements (p, q, r, s) in List II.

List I List II
A Cyton p  The body of the nerve cell that contains the organelles.
B Dendrite q Receives the stimuli sent from another nerve or the outside environment.
C Axon r A fatty substance that covers the axon of the nerve cell and speeds.
D Myelin sheath s The long, thin section of the nerve cell where the impulse is transmitted across.
biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

  1. A- p, B- q, C- s, D- r

  2. A- r, B- q, C- s, D- p

  3. A- r, B- s, C- q, D- p

  4. A- r, B- s, C- p, D- q

Show answer
Correct Option: A
Explanation:

Cyton is the cell body of the neuron. It contains the nucleus.

Dendrites are the cellular extension from the cyton. They receive stimulus, which may be physical, chemical, mechanical or electrical, and pass it on to the cyton.
Axons are also known as nerve fibres which are a projection of a nerve cell, or neuron, that typically conducts electrical impulses away from the neuron's cell body.
Myelin sheath is also known as the medullary sheath. It is the envelope of myelin that surrounds the core of a nerve fiber or axon and that facilitates the transmission of nerve impulses, formed from the cell membrane of the Schwann cell in the peripheral nervous system and from oligodendroglia cells. 
So, the correct answer is option C.

Pigmented dendritic cells occur in

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

  1. Stratum Malpighii

  2. Stratum granulosum

  3. Stratum corneum

  4. Stratum lucidum

Show answer
Correct Option: A
Explanation:

Epidermis is the outer part of skin, which is keratinised and composed of stratified squamous epithelium layers. In the structure of epidermis on the basis of shape of cells and cytoplasm, there are five stratum -
(1) Stratum Malpighii
(2) Stratum spinosum
(3) Stratum granulosum
(4) Stratum lucidum
(5) Stratum corneum
An innermost stratum of epidermis consisting of one layer of cells is called as stratum Malpighii. It is also called as stratum basale. Cells are cubical or columnar in shape. In this stratum two types of cells are present.

(i) Melanocytes - They are called pigmented dendritic cell. These cells are formed by modification of cell which lies at the junction of epidermis and dermis. 
(ii) Keratinocytes - They get their nutrition from underlying connective tissue of dermis and divide to form another stratum of the epidermis.

Nerve cells possess
(a) Dendrites
(b) Axon
(c) Sarcolemma
(d) Neurilemma

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

  1. a, b

  2. a, b, c

  3. a, b, d

  4. a, b, c, d

Show answer
Correct Option: C
Explanation:

Each mammalian neuron consists of a cell body, dendrites, and an axon. The cell body contains the nucleus and cytoplasm. The axon extends from the cell body and often gives rise to many smaller branches before ending at nerve terminals. Dendrites extend from the neuron cell body and receive messages from other neurons. 

The dendrites are covered with synapses formed by the ends of axons from other neurons. 
Neurilemma is the outermost nucleated cytoplasmic layer of Schwann cells that surrounds the axon of the neuron. 
The sarcolemma also called the myolemma, is the cell membrane of a striated muscle fiber cell. It is not present in the nerve cells.

Nissl granules are mostly present in 

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

  1. Axon

  2. Cyton

  3. Dendron

  4. Schwann cells

Show answer
Correct Option: B
Explanation:

A Nissl body is a large granular body found in neurons. These granules are rough endoplasmic reticulum (RER) with rosettes of free ribosomes and are the site of protein synthesis. These are present in cyton of the nerve cell.

So, the correct answer is option B.