Biology

Nervous System and Neurons

1,224 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 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"

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

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

  1. Rod cells

  2. Neurilemma

  3. Axons

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

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

Which one is absent in neurons ?

  1. Neurilemma

  2. Axon

  3. Sareolemma

  4. Dendrites
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sareolemma appears to be a misspelling of sarcolemma, which is the cell membrane of muscle fibres, NOT neurons. Neurons DO have neurilemma (Schwann cell membrane), axon, dendrites. The spelling error makes option C the correct answer as the absent structure.

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

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

The generation and propagation of an action potential in an axon are primarily driven by the rapid influx of sodium ions and the subsequent efflux of potassium ions.

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

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

Due to the decussation (crossing over) of nerve pathways in the central nervous system, sensory information from the right side of the body is processed in the left somatic sensory area of the brain.

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

Myelin sheath is derived from

  1. Neuroglial cells

  2. Schwann cells

  3. Nerve cells

  4. All of these
Reveal answer Fill a bubble to check yourself
B Correct answer
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'.