Biology

Nervous System and Neurons

1,164 Questions

The nervous system and neurons section covers the structural and functional aspects of the human nervous system. Topics include nerve fibers, the myelin sheath, and sympathetic nervous system functions. This material is crucial for general science preparation in various competitive exams.

Neuron structureMyelin sheath productionSympathetic nervous systemCranial and spinal nervesParasympathetic functions

Nervous System and Neurons Questions

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

The unmyelinated areas on myeliated nerve fibres are 

  1. Nodes of Ranvier

  2. Synaptic knobs

  3. Schwann cells

  4. Dendrite
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  1. Dendrites

  2. Axon

  3. Synaptic knob

  4. Myelin
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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.
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  1. Neurilemma

  2. Axolemma

  3. Oolemma

  4. Sarcolemma
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

  1. Axon

  2. Soma

  3. Dendrite

  4. Axon hillock
Reveal answer Fill a bubble to check yourself
A Correct answer
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.
Multiple choice biology plant and animal tissues nervous system in animals structure of neuron structure and function of neuron

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
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In medullated nerve fibers, the nodes of Ranvier are the specific points where the myelin sheath is interrupted and the axonal membrane comes into direct contact with the extracellular environment.

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

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
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The perikaryon (cell body) and dendrites are characteristic structures of a neuron that distinguish it from other typical animal cells. While other cells have nuclei and mitochondria, these specific extensions and the cell body structure are unique to neurons.

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

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
Reveal answer Fill a bubble to check yourself
C Correct answer
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'.

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

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

  1. Glial cells

  2. Schwann cells

  3. Dendrites

  4. Nissl bodies
Reveal answer Fill a bubble to check yourself
A Correct answer
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"