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Structure and function of neuron - class-X

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The bulbous structure present at the terminal end of an axon is_______________

  1. Synaptic vesicle

  2. Synaptic knob

  3. Dendrites

  4. Schwann cell


Correct Option: B
Explanation:

A. Synaptic vesicle store various neurotransmitters that are released at the synapse.

B. Synaptic knob-The bulbous structure present at the terminal end of an axon.

c. Dendrites-also dendrons, are branched protoplasmic extensions of a nerve cell that propagate the electrochemical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project.

D. Schwann cell -also called neurilemma cell, any of the cells in the peripheral nervous system that produce the myelin sheath around neuronal axons.

So, the correct option is 'Synaptic Knob'.

Name the part of the neuron, where information is acquired.

  1. Axon

  2. Dendrites

  3. Synapse

  4. Schwann cells


Correct Option: B
Explanation:
Neuron is a structural and functional unit of neural system. It is composed of three major parts- cell body, dendrites and axon.
A. Axon is a long fibre which arises from the cell body and terminates as a bulb-like structure called the synaptic knob which participate in synapse. Hence, the axons take away the information from the cell body of the neuron to which they belong.
B. Dendrites are the short fibers which arise out from the cell body. The dendrites of one neuron receive the electrical impulses from different sources and then transmit these impulses towards the cell body of the neuron to which they belong. Hence, the information is acquired here.
C. Synapse is the nerve impulse which is transmitted from one neuron to another through the junctions. It is formed by the membranes of the pre-synaptic neuron and a post-synaptic neuron.
D. Schwann cells are enclosed in myelin sheath and are lipid rich cells.
So, the correct option is 'Dendrites'.

Name the part of neuron through which information travels as an electrical impulses.

  1. Dendrites

  2. Axon

  3. Schwann cells

  4. Sypase


Correct Option: B
Explanation:
An axon is a long, slender projection of a neuron, that typically conducts electrical impulses away from the neuron's cell body in form of a wave of depolarization. The function of the axon is to transmit information to different neurons, muscles and glands.
So, the correct option is 'Axon'.

Centrosome includes a pair of centrioles that help in cell division by spindle formation. The non-dividing cells in human are

  1. Chondrocytes

  2. Epithelial cells

  3. Neurons

  4. Neuroglial cells


Correct Option: C
Explanation:
A. Chondrocytes are the cells that are found in cartilage. These cells can divide forming a nest of 2-4 cells.
B. Epithelial cells are the cells lining the surfaces of the body. These cells can also divide by mitosis.
C. Neurons or the nerve cells are the largest cells in the body and found in the nervous system. These cells do not have centrioles and hence, do not undergo cell division.
D. Neuroglial cells are the cells in the central nervous system, other than neurons. These cells are meant for the protection of neurons and can divide by mitosis.
Hence, non-dividing cells in humans are neurons.

So, the correct answer is 'Neurons'.

Neurilemma is name for :

  1. Plasmamembrane of axon

  2. Coating formed by myelin sheath

  3. Covering of schwann cells

  4. Connective tissue covering of nerve fasciculus


Correct Option: C
Explanation:

Neurilemma is the outermost covering of Schwann cells that surrounds the axon of the neuron. It is also known as neurolemma.

Thus, the correct answer is 'Covering formed by Schwann cells.'

Which one of the following pairs of structures distinguishes a nerve cell from other cell types?

  1. Vacuoles and fibres

  2. Flagellum and medullary sheath

  3. Nucleus and mitochondria

  4. Perikaryon and dendrites


Correct Option: D
Explanation:

The vacuole is membrane bound organelle present in all plant and fungal cells and some protist, animal and bacterial cells. The flagellum is an appendage, that protrudes from the cell body of certain prokaryotic and some eukaryotic cells. Nucleus and mitochondria are membrane bound organelles present in almost all cells. Perikaryon, also called cyton is the bulbous end of a neuron containing cell nucleus. Dendrites are the short cytoplasmic processes of the cell body of the neuron, which receives stimulus from other neurons. 
So, the correct answer is option D.

In peripheral nervous system, the nerves are made up exclusively from the

  1. Dendrons

  2. Axons

  3. Nodes of Ranvier

  4. Nissl body


Correct Option: B
Explanation:

Nerves are made up of bundles of the axons of nerve cells. A nerve is an enclosed, cable-like bundle of axons (long, slender projections of neurons) in the peripheral nervous system.

'Nodes of Ranvier' are found in 

  1. Brain

  2. Heart

  3. Axon

  4. Eye


Correct Option: C
Explanation:

Nodes of Ranvier are periodic gaps in the insulating sheath (myelin) on the axon of certain neurons, that serves to facilitate the rapid conduction of nerve impulses. 

The action potential propagated by one node of Ranvier jumps to and is regenerated at the next node along the axon, thereby enabling the action potential to travel rapidly along the fiber.

The function of an axon is 

  1. Transformation of nerve impulse

  2. Reception of stimuli from neurons

  3. Reception of external stimuli

  4. Conduction of nerve impulse


Correct Option: D
Explanation:

An axon is also known as a nerve fiber. It is a long, slender projection of a nerve cell, or neuron, that 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.

Sheath of Schwann occurs on 

  1. Neurons

  2. Axons

  3. Dendrons

  4. Neuroglia


Correct Option: B
Explanation:

Schwann cells also called as neurolemmocytes are the principal glia of the peripheral nervous system (PNS). Myelinating Schwann cells wrap around axons of motor and sensory neurons to form the myelin sheath. 

What used to be described as Nissl granules in a nerve cell are now identified as?

  1. Cell metabolites

  2. Fat granules

  3. Ribosomes

  4. Mitochondria


Correct Option: C
Explanation:

A Nissl granule 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.

Dendrites are associated with which system?

  1. Nervous system

  2. Digestive system

  3. Muscular system

  4. Blood vascular system


Correct Option: A
Explanation:

Dendrites are the branched projections of a neuron, that act to propagate the electrochemical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project.

The Nissl granules of nerve cells are made up of 

  1. Ribosome

  2. Protein

  3. DNA

  4. Mitochondria


Correct Option: A
Explanation:

A Nissl granule 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.

Nissl granules are found in 

  1. Liver cells

  2. Nerve cells

  3. Kidney

  4. Heart


Correct Option: B
Explanation:

A Nissl body is also known as Nissl or tigroid substance. It is a large granular body found in neurons. These granules are rough endoplasmic reticulum (RER) with rosettes of free ribosomes and are the sites of protein synthesis.

Nissl's granules are

  1. RNA bodies

  2. DNA

  3. Carbohydrate

  4. Protein


Correct Option: A
Explanation:

A Nissl body is also known as Nissl or tigroid substance. It 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.

"Nodes of Ranvier" are found in 

  1. Brain

  2. Heart

  3. Axon

  4. Eye


Correct Option: C
Explanation:

The node of Ranvier is a periodic gap in the insulating sheath on the axon of certain neurons that serves to facilitate the rapid conduction of nerve impulses. These interruptions in the myelin covering were first discovered in 1878 by French histologist and pathologist Louis Antoine Ranvier, who describes the nodes as constrictions. They are present in myelinated nerves.

Power of regeneration is lowest in 

  1. Brain cell

  2. Liver cell

  3. Bone cell

  4. Muscle cell


Correct Option: A
Explanation:

The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. In a typical human, the cerebral cortex is estimated to contain 15-33 billion neurons, each connected by synapses to several thousand other neurons. These  neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells. These brain cells are the only cells which do not have the ability to regenerate.

Therefore, the correct answer is option A.

What is the function of neuron?

  1. It helps in conducting impulses.

  2. It helps in regulating control and coordination in the animals.

  3. Both A and B.

  4. None of the above.


Correct Option: C
Explanation:

A neuron is an electrically excitable cell. It processes and transmits information through electrical and chemical signals. These signals between neurons occur via synapses, specialized connections with other cells. Neurons can connect to each other to form neural networks. Neurons are the core components of the nervous system, which includes the brain, spinal cord which together comprise the central nervous system (CNS) and the ganglia of the peripheral nervous system (PNS). Specialized types of neurons include: sensory neurons which respond to touch, sound, light and all other stimuli affecting the cells of the sensory organs that then send signals to the spinal cord and brain, motor neurons that receive signals from the brain and spinal cord to cause muscle contractions and affect glandular outputs and interneurons which connect neurons to other neurons within the same region of the brain or spinal cord in neural networks.
Therefore, the correct answer is option C.

All information from our environment is detected by the specialized .................. cells.

  1. Nerve

  2. Nephron

  3. Glial

  4. Companion


Correct Option: A
Explanation:

The two main types of cells of the nervous system are neurons/nerve cells and neuroglia. The main function of neurons is to receive sensory inputs from the internal and external environment by sensory nerves and transmit it to CNS (brain and spinal cord) for processing and finally transmit the nerve impulses from CNS to effectors (muscles and glands).

Neuroglia/glial cells support and nourish the nerve cells, destroy pathogen and modulate the impulse transmission.  
The nephron is the anatomical and functional unit of kidney and thus is the part of the excretory system. 
Companion cells are the component of phloem in flowering plants and regulate loading and unloading of sugars into sieve tube elements for translocation. 
Therefore, the correct answer is option A.

Main parts of a neuron are ............... and 

  1. Cell body, axon

  2. Axon hillock, synaptic knob

  3. Cell body, synaptic knob

  4. Myelin seath, axon


Correct Option: A
Explanation:

The basic parts of a neuron are the dendrites, the cell body and the axon. However, all neurons vary somewhat in size, shape and characteristics depending on the function and role of the neuron. Some neurons have few dendritic branches, while others are highly branched in order to receive a great deal of information. Some neurons have short axons, while others can be quite long. The longest axon in the human body extends from the bottom of the spine to the big toe and averages a length of approximately three feet.

Therefore, the correct answer is option A.

................... is the functional and structural unit of the nervous system.

  1. Neuron

  2. Nephron

  3. Cerebrum

  4. Cerebellum


Correct Option: A
Explanation:

A neuron is an electrically excitable cell. It is the functional and structural unit of the nervous system. It processes and transmits information through electrical and chemical signals. These signals between neurons occur via synapses, specialized connections with other cells. Neurons can connect to each other to form neural networks. Neurons are the core components of the nervous system.

Which cell organelle is absent in neuron?

  1. Mitochondria

  2. Ribsomes

  3. Centrioles

  4. Nucleus


Correct Option: C
Explanation:

A centriole is a small set of microtubules arranged in a specific way. There are nine groups of microtubules. When two centrioles are found next to each other, they are usually at right angles. The centrioles are found in pairs and move towards the poles (opposite ends) of the nucleus when it is time for cell division. Neurons cannot divide because they lack centrioles.
Because centrioles function in cell division, the fact that neurons lack these organelles is consistent with the amitotic nature of the cell.

Therefore, the correct answer is option C.

Which of the following is not a function of neuron?

  1. Receive information

  2. Conduct a signal

  3. Form the myelin sheath

  4. Co-ordinate metabolic activities


Correct Option: C
Explanation:

Sensory neurons receive sensory inputs from the internal and external environment by sensory nerves and transmit it to CNS (brain and spinal cord) for processing. This makes option A incorrect. 

Motor neurons transmit the nerve impulses from CNS to effectors (muscles and glands). 
According to the signal, carried by motor nerves to effector organs, the muscles and glands perform their actions (contraction and secretion respectively) and thereby coordinating the metabolic activities. Thus, option D is incorrect. 
The two main types of cells of the nervous system are neurons and neuroglia. The myelinated axon fibres are covered with white myelin sheath formed from the membranes of tightly spiraled neuroglia cells. Thus, option C is the correct answer. 

A nerve is composed of

  1. Muscular tissue

  2. Nerve fibre bundles

  3. Bundle sheaths

  4. None of the above


Correct Option: B
Explanation:

A nerve is composed of nerve fiber bundles. A nerve fiber is a threadlike extension of a nerve cell and consists of an axon and myelin sheath (if present) in the nervous system. There are nerve fibers in the central nervous system and peripheral nervous system. A nerve fiber may be myelinated and/or unmyelinated. In the central nervous system (CNS), myelin is produced by oligodendroglia cells.
Muscle tissue is a soft tissue that composes muscles in animal bodies and gives rise to muscles ability to contract. This is opposed to other components or tissues in muscle such as tendons or perimysium.
Bundle sheath cells is a layer of cells in plant leaves and stem that forms a sheath surrounding the vascular bundles.

Therefore, the correct answer is option B.

The speed at which impulses are conducted increase with  

  1. Increasing diameter of the soma

  2. Increasing diameter of the axon

  3. Increasing number of dendrites

  4. Increasing branching of the dendrites


Correct Option: B
Explanation:

Dendrites are the small extension of nerve cells that receive signals from sensory receptors or other neurons. The nerve impulse is not conducted by them. The long extension of the cell body of the nerve cell is called as axon that serves to conduct the nerve impulse away from the cell body. The increased diameter of axon results in reduced resistance to local current flow which in turn causes the action potential at its one site to activate the adjacent site. Soma is the metabolic center of the nerve cell where the metabolic contents are manufactured. It is not involved in nerve impulse conduction. Thus, the correct answer is option B.

The unmyelinated areas on myeliated nerve fibres are 

  1. Nodes of Ranvier

  2. Synaptic knobs

  3. Schwann cells

  4. Dendrite


Correct Option: A
Explanation:

Schwann/Schwarm cells of peripheral nervous system form the myelin sheath around the myelinated fibers. Gaps between two Schwann cells form nodes of Ranvier which are the unmyelinated areas. Dendrites are the small extension of nerve cells that receive signals from sensory receptors or other neurons and brings them towards the cell body. The synaptic knob is the small button like structure present at the end of the axonal branch at the synapse and serves to store the neurotransmitters which are released in the synaptic cleft. The correct answer is A.

The part of neuron which brings information towards the cell body is

  1. Dendrites

  2. Axon

  3. Synaptic knob

  4. Myelin


Correct Option: A
Explanation:

Dendrites are the small extension of nerve cells that receives signals from sensory receptors or other neurons through axon and brings them towards the cell body. Thus, the correct answer is option A.

What are neurotransmitters?

  1. Transmit signals across synapse.

  2. Transmit signal in the cell body.

  3. Take the signal to the axon.

  4. None of the above.


Correct Option: A
Explanation:

Neurotransmitters are endogenous chemicals that enable the process of neurotransmission. They transmit signals across a chemical synapse from one neuron (nerve cell) to another "target" neuron, muscle cell, or gland cell. 

Therefore, the correct answer is option A.

Which of the following tissues in mammals show least capacity for regeneration?

  1. Blood

  2. Bone

  3. Nerve

  4. Cartilage


Correct Option: C
Explanation:
  • The different cells in the body can regenerate in order to replace the damaged or the worn-out cells. 
  • The neurons are one of the brain cells. The cells divide during the embryonal stage. After the birth of a child, the cells lose their capacity to divide. 
  • These cells have the least capacity of regeneration. 
  • Thus, the correct answer is option C. 

Myelin sheath is a layer covering

  1. A nerve fibre in a vertebrate

  2. A chick embryo

  3. A muscle fibre in a vertebrate

  4. None of the above


Correct Option: A
Explanation:

The axon can be defined as the long cytoplasmic process of the cell body, which transmits the impulse from the cell body to other neurons. The axon of the neuron is covered by a lipid-rich membrane, called myelin sheath. The myelin sheath is formed by Schwann cells and each Schwann cell covers a part of the axon.
Thus, the correct answer is the option D.

The afferent process of neuron is known as

  1. Axon

  2. Dendrite

  3. Cyton

  4. Neurofibrillary tangle


Correct Option: B
Explanation:

The dendrites of the neuron are called as 'afferent processes' because they transmit impulses to the neuron cell body.
Thus, the correct answer is the option (B), 'Dendrite'.

Nerve cells do not possess

  1. Neurilemma

  2. Sarcolemma

  3. Dendrite

  4. Axon


Correct Option: B
Explanation:

Cells of the nervous system are called nerve cells or neurons. Neurons have specialized cell parts, called dendrites and axons. A thin sheath covers the axon of the nerve cell. This sheath is called as neurilemma. The sarcolemma also called the myolemma, is the cell membrane of a striated muscle fiber cell. It is not present in the nerve cell. 

The outer covering of non-myelinated neurons in brain is?

  1. Neurilemma

  2. Axolemma

  3. Oolemma

  4. Sarcolemma


Correct Option: B
Explanation:

Unlike unmyelinated axons in periphary nerves which an embedded in neurilemma of Schwann cells, those of central nerves lie free in neuropil(nertwork of glial cells and nerve cell components).

So the correct option is B.

Nissl granules are absent in _________.

  1. Neuron

  2. Axon

  3. Cyton

  4. Dendrite


Correct Option: B

Which of the following possesses nodes of Ranvier?

  1. Medullated nerve fibre

  2. Non-medullated nerve fibre

  3. Muscle fibre

  4. Medullated and non-medullated nerve fibres


Correct Option: A

Nissl granules found in cyton of a neuron and having affinity for basic dyes are composed of _________.

  1. DNA

  2. RNA

  3. Proteins

  4. Amino acids


Correct Option: B

In a neuron, Schwann cells occur in associated with ____________.

  1. Axon

  2. Soma

  3. Dendrite

  4. Axon hillock


Correct Option: A
Explanation:
Answer is option A i.e. "Axon"
Schwann cells cover the surface of all axons. Hence, Schwann cells are found in close contact with axons in the peripheral nerves. Schwann cells form the myelin sheath and are the main glial cells in the peripheral nervous system.

In medullated nerve fibre, nodes of Ranvier represent areas ______________.

  1. Swellings on axon

  2. Myelin sheath touches axon

  3. Swelling on cyton

  4. Depressions found on cyton


Correct Option: B

Nissl's granules are made of ______________.

  1. Ribosomes$/$RER

  2. SER

  3. DNA

  4. Golgi bodies


Correct Option: A

Nissl granules occur in _____________.

  1. Bone cells

  2. Mast cells

  3. Nerve cells

  4. Chondrocytes


Correct Option: C

Nodes of Ranvier occur in ____________.

  1. Cell body

  2. Right atrium

  3. Right ventricle

  4. Medullated nerve fibres


Correct Option: D

Which pair of structures distinguishes a nerve cell from other cells?

  1. Vacuole and fibres

  2. Nucleus and mitochondria

  3. Perikaryon and dendrites

  4. Flagellum and medullary sheath


Correct Option: C

Myelin sheath is formed from ______________.

  1. Nerve cells

  2. Glial cells

  3. Schwann cells

  4. None of the above


Correct Option: C

Which part of neuron is covered by fatty sheath?

  1. Axon

  2. Cyton

  3. Dendrite

  4. Node of Ranvier


Correct Option: A

The area where medullary sheath is absent in the nerve fibre is

  1. Nissl granules

  2. Schwann cells

  3. Node of Ranvier

  4. Schwann node


Correct Option: C
Explanation:

The medullary sheath is composed of a shinning, white, fatty substance called myelin. This sheath perhaps serves as an insulating layer, preventing loss of energy of the nerve impulse during its passage along the fibre. The medullary sheath is continuous around the fibres in the central nervous system, but in the fibres of the peripheral nerves, it is absent at certain points known as the Node of Ranvier. The part of a nerve fibre between two successive nodes is termed the internode.

So, the correct answer is 'Node of Ranvier'.

Choose the odd pair.

  1. Areolar connective tissue - Collagen

  2. Epithelium - Keratin

  3. Muscle fibre - Actin

  4. Neuron - Melanin


Correct Option: D

Non-excitable variously shaped cells found between neurons are ________________.

  1. Glial cells

  2. Schwann cells

  3. Dendrites

  4. Nissl bodies


Correct Option: A
Explanation:

Answer is option A i.e. "Glial cells"
Glial cells- These cells are the helper cells in the central nervous system. They surround the neurons and provide insulation between two neurons. There are variously shaped like oligodendrocytes, astrocytes (star-shaped), ependymal etc.
Dendrites- They are branched extensions of nerve cells.
Nissl bodies- It is a large granular body found in the neuron cells.
Schwann cell- They are present in the axon of a neuron. They help in supporting nerve regeneration.
Thus the correct answer is "Glial cells"

On nerve fibres, to prevent leakage of an impulse, a layer of ...... is found.

  1. Rod cells

  2. Neurilemma

  3. Axons

  4. Myelin sheath


Correct Option: D
Explanation:

Myelin is an insulating layer, or sheath, that forms around nerves. It is made up of protein and fatty substances. The fat helps to insulate the axons from electrically charged atoms and molecules. The purpose of the myelin sheath is to allow electrical impulses to transmit quickly and efficiently along the nerve cells.

Some cell in our body can be over a feet long. They are

  1. Muscle cells

  2. Bone cells

  3. Nerve cells

  4. Gland cells


Correct Option: C
Explanation:

Certain neurons or nerve cells may almost equal the length of body itself. The axon of a motor neuron in the spinal cord, that innervates a muscle in the foot can be about 1 meter (3 feet) in length.

Which one is absent in neurons ?

  1. Neurilemma

  2. Axon

  3. Sareolemma

  4. Dendrites


Correct Option: C

The charge on the outer side of neuron is

  1. +ve

  2. -ve

  3. Zero

  4. Alternate -ve and +ve


Correct Option: A

In axon of a neuron, the impulse is generated by exchange of

  1. Sodium and chlorine

  2. Magnesium and chlorine

  3. Calcium and potassium

  4. Sodium and potassium


Correct Option: D

Touch on the right side stimulate neurons on

  1. Right somatic sensory area

  2. Right somatic motor area

  3. Left somatic sensory area

  4. Both B and C


Correct Option: C

Myelin sheath is derived from

  1. Neuroglial cells

  2. Schwann cells

  3. Nerve cells

  4. All of these


Correct Option: B
Explanation:

  • Myelin sheath is formed by oligodendrocytes in the CNS and by Schwann cells in the peripheral nervous system. 
  • These cells wrap layer upon layer of their own plasma membrane in a tight spiral around axon. 
  • 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'.

End plate junction is present between

  1. Neuron and striated muscle

  2. Neuron and neuron

  3. Muscle and muscle

  4. Both (b) and (c)


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?

  1. Satellite glial cells

  2. Radial glial cells

  3. Dendrocytes

  4. Schwann cells


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

  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


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?

  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.


Correct Option: A

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

  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


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

  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


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

  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


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.

  1. Axon

  2. Dendron

  3. Schwann cell

  4. None of the above


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

  1. Integrate signals from the dendrites

  2. Release neurotransmitter

  3. Conduct the impulse to the synaptic terminal

  4. Synthesize cellular components


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

  1. Metabolism

  2. Growth

  3. Contractility

  4. Irritability


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.
  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


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

  1. Stratum Malpighii

  2. Stratum granulosum

  3. Stratum corneum

  4. Stratum lucidum


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

  1. a, b

  2. a, b, c

  3. a, b, d

  4. a, b, c, d


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 

  1. Axon

  2. Cyton

  3. Dendron

  4. Schwann cells


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.

Which one of the following pairs of structure distinguishes a nerve cell from other types of cell?

  1. Flagellum and medullary sheath

  2. Nucleus and mitochondria

  3. Perikaryon and dendrites

  4. Vacuoles and fibres


Correct Option: C
Explanation:
  • The structural difference between a neuron and other kinds of cell include the perikaryon and dendrites.
  • The cell body of a neuron, known as perikaryon, has a large and round nucleus. Nissil granules are present in its cytoplasm forming the characteristic feature.
  • While dendrites are branched thread like structure arising from cyton which functions to receive impulses from sensory system and transfer it in form of electrical impulses to other neurons via the Axon.
So, the correct option is 'Perikaryon and Dendrites'.

Select the correct statement regarding the Schwann cells.

  1. Surround axon of myelinated nerve fibre

  2. Support muscle fibres

  3. Found in Haversian system of bones

  4. Form basement membrane of epithelium.


Correct Option: A
Explanation:
Schwann cell, also called neurilemma cell, any of the cells in the peripheral nervous system that produce the myelin sheath around neuronal axons. Myelin, which is a fatty layer that insulates the axon, helps to increase the saltatory conduction of the neuron. 
So, the correct answer is option A.

The core component of central nervous system is 

  1. Blood

  2. Neurons

  3. Ganglia

  4. Both A and B


Correct Option: B
Explanation:
  • Neurons are the basic units of the nervous system. Every neuron is made of a cell body (also called a soma), dendrites and an axon. Dendrites and axons are nerve fibres.
  • The central nervous system consists of the brain and the spinal cord
  • The human brain contains around 100 billion neurons.
  • Hence the core component of the central nervous system is  Neuron.
  • So, the correct answer is 'Neurons'.

A minute gap across which impulse pass by neurotransmitter is called as a 

  1. Cleft

  2. Synapse

  3. Nerve impulse

  4. None of the above


Correct Option: B
Explanation:

The gap between two neurons across which impulses are conducted is known as a synapse. Synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell. It is important for neuronal function. 
Thus, the correct answer is option B.

Area of coming together of two neuron ends or between a dendron and axon ends is?

  1. Junction

  2. Synapsis

  3. Synapses

  4. Synapticula


Correct Option: C
Explanation:

  • In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. 
  • Synapses are stabilized in position by synaptic adhesion molecules (SAMs) projecting from both the pre- and post-synaptic neuron and sticking together where they overlap. Hence. Area of coming together of two neuron ends or between a dendron and axon ends is synapses.
So, the correct answer is 'synapses'.

A small gap that helps neurotransmitter to pass nerve impulse is called as

  1. Neuron

  2. Synapse

  3. Ganglia

  4. None of the above


Correct Option: B
Explanation:

The gap between two neurons across which impulses are conducted is known as a synapse. The presynaptic is the region of the axonic end of one neuron and the post synaptic is the dendritic end of the other neuronIt is a structure that permits a neuron to pass an electrical or chemical signal to another cell and acts as a communication point between the neuron and the target organ. The nerve impulses are transmitted and received with the help of this regions. 
Thus, the correct answer is option A.

The junction between two neurons is called as a synapse.
  1. True

  2. False


Correct Option: A
Explanation:
Synapse, also called neuronal junction, the site of transmission of electric nerve impulses between two nerve cells (neurons) or between a neuron and a gland or muscle cell (effector). A synaptic connection between a neuron and a muscle cell is called a neuromuscular junction.

So, the correct answer is 'True'.

In which region nerve impulses are transmitted and received? 

  1. Nodes of Ranvier

  2. Dendrites

  3. Axon

  4. Synapse


Correct Option: D
Explanation:

The gap between two neurons across which impulses are conducted is known as a synapse. The presynaptic is the region of the axonic end of one neuron and the post synaptic is the dendritic end of the other neuronIt is a structure that permits a neuron to pass an electrical or chemical signal to another cell. It is important for neuronal function. The nerve impulses are transmitted and received with the help of this regions. 
Thus, the correct answer is option D.

Which of the following statements explain the meaning of synapse.

  1. Junction of two nerve cells.

  2. Junction of two muscle cells.

  3. Junction of two bone cells.

  4. Junction of two sperm cells.


Correct Option: A
Explanation:

  • Synapse, also called neuronal junction, the site of transmission of electric nerve impulses between two nerve cells (neurons) or between a neuron and a gland or muscle cell (effector)
  • . A synaptic connection between a neuron and a muscle cell is called a neuromuscular junction. 

So, the correct answer is 'Junction of two nerve cells'.

What do will the microscope gap between a pair of adjacent neurons over which impulse passes?

  1. Synapse

  2. Axon

  3. Dendrite

  4. Cell body

  5. None of these


Correct Option: A
Explanation:

  • When a nerve impulse reaches the synapse at the end of a neuron, it cannot pass directly to the next one instead it triggers the neuron to release a chemical neurotransmitter. The neurotransmitter drifts across the gap between the two neurons.

So, the correct option is'Synapse'

Neurons have a unique property that makes them to communicate with other cells via

  1. Nerve code

  2. Glacial cells

  3. Synapses

  4. Schwinn cells


Correct Option: C
Explanation:

Synapse is a gap between two neurons which is filled with a neurotransmitter such as acetylcholine. It functions to transfer one neuronal signal to other by acting as a bridge. It allows the electrical signal to be converted into a chemical signal. So, the correct answer is option C.

The gap between two neurons is known as

  1. Dendrite

  2. Synapse

  3. Axon

  4. Impulse


Correct Option: B
Explanation:
Neuron is the structural and functional unit of nervous system. It consists of dendrites, axon and soma. Dendrites are the small extension of nerve cells that receives signals from sensory receptors or other neurons.
The long extension of cell body of nerve cell is called as axon that serves to conduct the nerve impulse away from the cell body.
Two neurons are never physically connected to each other and synapse place where two neurons are in close connection to facilitate transmission of information from one neuron to the next one.
The extracellular space between two neurons is known as synaptic cleft. Nerve impulse is all or none response of nerve fibres and is defined as wave of change in polarity of neuron membrane, caused by movement of ions across the membrane.
So, the correct answer is option B. 

Which of the following chemical is released in synapse?

  1. Acetylcholine

  2. Choline

  3. Acetyl CoA

  4. None of the above


Correct Option: A
Explanation:

Neurotransmitters are the chemicals that transmit the nerve impulse across the synapse. Acetylcholine is the neurotransmitter produced by cholinergic neuron. It is secreted by both pre- and post-ganglionic parasympathetic cholinergic neurons in synapse.

Thus, the correct answer is option A.

The word synapse was coined in 

  1. 1897

  2. 1997

  3. 1797

  4. 1957


Correct Option: A
Explanation:

The term synapse was first introduced in 1897 by neurophysiologist Charles Sherrington. The gap between two neurons across which impulses are conducted is known as a synapse. Synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell. It is important for neuronal function. 
Thus, the correct answer is option A.

A place where a signal passes from one nerve cell to next is described as 

  1. Synaptic cleft

  2. Synapsis

  3. Synapse

  4. Symport movement


Correct Option: C
Explanation:

The gap between two neurons across which impulses are conducted is known as a synapse. Synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell. It is important for neuronal function. 
Thus, the correct answer is option C.

Which structure of nervous system permits a neuron to pass impulse to another neuron?

  1. Nerve fiber

  2. Dendrites

  3. Synapse

  4. Axon


Correct Option: C
Explanation:

The gap between two neurons across which impulses are conducted is known as a synapse. Synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell. It is important for neuronal function. 
Thus, the correct answer is option C.

Which of the following is the component of the synapse?

  1. Presynaptic component

  2. Postsynaptic component

  3. Both A and B

  4. Nerve impulse


Correct Option: C
Explanation:

The gap between two neurons across which impulses are conducted is known as a synapse. The presynaptic is the region of the axonic end of one neuron and the post synaptic is the dendritic end of the other neuronIt is a structure that permits a neuron to pass an electrical or chemical signal to another cell and acts as a communication point between the neuron and the target organ. 
Thus, the correct answer is option C.

The point of communication and target cell is

  1. Synapse

  2. Nodes of Ranvier

  3. Dendrites

  4. Sense organs


Correct Option: A
Explanation:

The gap between two neurons across which impulses are conducted is known as a synapse. The presynaptic is the region of the axonic end of one neuron and the post synaptic is the dendritic end of the other neuronIt is a structure that permits a neuron to pass an electrical or chemical signal to another cell and acts as a communication point between the neuron and the target organ. It is important for neuronal function. The nerve impulses are transmitted and received with the help of this regions. 
Thus, the correct answer is option A.

Presynaptic ending contains 

  1. Mitochondria

  2. Lysosomes

  3. Centrioles

  4. All of the above


Correct Option: A
Explanation:
  • The synapse consists of :
1) presynaptic ending that contains neurotransmitters, and supporting cell organelles like mitochondria and endoplasmic reticulum. 
2) postsynaptic ending contains receptor sites for neurotransmitters. and 3)synaptic cleft is the space between the presynaptic and postsynaptic endings.
The function of mitochondria in presynaptic endings is the calcium homeostasis.
  • Hence Presynaptic ending contains Mitochondria.
  • So, the correct answer is 'Mitochondria'.

Joint between axon of a neuron and dendrite of next is called

  1. Synapse

  2. Synapsis

  3. Junction

  4. Bridge


Correct Option: A

Synapse is......

  1. Crossing over between nonhomologous chromosomes

  2. Pairing of homologous chromosomes

  3. Junction between axon and dendrite of two different neurons

  4. Zigzag junction in cardiac muscle fibres


Correct Option: C

Association between telodendria and dendrites is known as

  1. Synapse

  2. Aynapse

  3. Trinapse

  4. Dynapse


Correct Option: A

Which of the following options correctly described the sequence of structures present between a receptor and an effector when D refers dendrite, A refers axon, S refers synapse and CB refers to cell body?

  1. D - CB - A - S - D - CB - A

  2. A -D - CB - S - A - D - CB

  3. D - CB - A - S - A - CB - D

  4. D - A - S - CB - D - A - CB


Correct Option: A

The chemicals which are released at the synaptic junction are known as

  1. Cerebrospinal fluid

  2. Hormones

  3. Neurotransmitters

  4. Lymph


Correct Option: C
Explanation:

Neurotransmitters are the brain chemicals that communicate information throughout our brain and body. They relay signals between nerve cells called as neurons. They are the chemicals which allow the transmission of signals from one neuron to the next across synapses. They are also found at the axon endings of motor neurons, where they stimulate the muscle fibres. So, the correct answer is option C.

Select the option responsible for restoring resting membrane potential of a neuron

  1. Voltage gated ${ Na }^{ + }$ channels

  2. Voltage gated ${ K }^{ + }$ channels

  3. Leaky channels for ${ K }^{ + }$

  4. ${ Na }^{ + }/{ K }^{ + }$ pump


Correct Option: D
Explanation:

The Sodium-Potassium pump is the process of moving sodium and potassium ions across the cell membrane is an active transport process involving the hydrolysis of ATP to provide the necessary energy. It involves an enzyme referred to as Na+/K+.

So, the correct option is 'Na+/K+ pump'.

Nerve impulse generation is a

  1. Physical process

  2. Chemical process

  3. Effected process

  4. Electro-chemical process


Correct Option: D
Explanation:
A nerve impulse is a way nerve cells (neurons) communicate with one another. Nerve impulses are mostly electrical signals along the dendrites to produce a nerve impulse or action potential. The action potential is the result of ions moving in and out of the cell.

In thinking and response to external stimulus the brain take time about

  1. Less than 1/10th sec

  2. 1/10th sec

  3. More than 1/10th sec

  4. About 1 sec


Correct Option: B
Explanation:

The human nervous system is highly developed. The external stimulus leads to generation of impulse. This impulse is conducted through sensory neurons and the response is given by the effector organ on receiving the answer given by the brain. The time taken by the brain and the nervous system to give the response is considered as in fraction of a second. So, the correct answer is option B.

You are watching a horror movie and you notice your heart is beating fast and mouth is dry; it is because

  1. Fight and flight response

  2. Autonomic nervous system

  3. Sympathetic nervous system

  4. Both A and C

  5. Release of acetylcholine


Correct Option: D
Explanation:
You are watching a horror movie and you notice your heart is beating fast and mouth is dry; it is because of fight and flight response and sympathetic nervous system.
Fight and flight response is acute stress response.
The fight-or-flight response occurs in response to a perceived harmful event, attack, or threat to survival. The sympathetic nervous system originates in the spinal cord and its main function is to activate the physiological changes that occur during the fight-or-flight response. This component of the autonomic nervous system utilizes and activates the release of norepinephrine in the reaction.
The physiological changes that occur during the fight or flight response are activated in order to give the body increased strength and speed in anticipation of fighting or running. Some of the specific physiological changes and their functions include:
Increased blood flow to the muscles activated by diverting blood flow from other parts of the body.
Increased blood pressure, heart rate, blood sugars, and fats in order to supply the body with extra energy.
The blood clotting function of the body speeds up in order to prevent excessive blood loss in the event of an injury sustained during the response.
Increased muscle tension in order to provide the body with extra speed and strength.

Sight of delicious food usually makes mouth watery, it is a 

  1. Hormonal response

  2. Neural response

  3. Optic response

  4. Olfactory response


Correct Option: B
Explanation:

The response to food begins even before food enters the mouth. The first phase of ingestion, called as the cephalic phase, is controlled by the neural response to the stimulus provided by food. All aspects, such as sight, sense, and smell, trigger the neural responses resulting in salivation and secretion of gastric juices. The gastric and salivary secretion in the cephalic phase can also take place at the thought of food. The central nervous system prepares the stomach to receive food. 

Who discovered synapse?

  1. R. Y. Cahal

  2. Sherrington

  3. Otto Loewi

  4. None of the above


Correct Option: B
Explanation:

The term synapse was first discovered in 1897 by neurophysiologist Charles Sherrington. The gap between two neurons across which impulses are conducted is known as a synapse. Synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell. It is important for neuronal function. 
Thus, the correct answer is option B.

Destruction of the anterior horn cells of the spinal cord would result in loss of

  1. Sensory impulses

  2. Voluntary motor impulses

  3. Commissural impulses

  4. Integrating impulses.


Correct Option: B
Explanation:

Anterior horn cells are the ventral (front) grey matter section of the spinal cord which contains motor neurons that affect the skeletal muscles. It is also known as anterior grey column, ventral horn. The anterior grey column is the column where the cell bodies of alpha motor neurons are located. The destruction of the anterior horn cells of the spinal cord would result in loss of voluntary motor impulses because it is mainly related to motor impulses.

So, the correct answer is option B. 

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