Myelinated and Unmyelinated Fibres

Q. What is true about unmyelinated nerve fiber?

1. Not enclosed by both Schwann cells and a myelin sheath.
2. Enclosed by a Schwann cell that does not form a myelin sheath.
3. Not found in the autonomous and the somatic neural system.
4. Not enclosed by a Schwann cell but enclosed by a myelin sheath.

Q. Why is the membrane of a neuron polarised?

Q.

Define Axon.

Q. The velocity of action potential propagation

1. Is independent of an axon's diameter
2. Depends on the thickness of the myelin around the axon
3. Will be unaffected if the axon becomes demyelinated
4. Is fastest in non-myelinated axons.

Q.

Define-

1. Axoplasm
2. Axolemma

Q.

Nodes of Ranvier is absent in non-myelinated neuron

1. True
2. False

Q.

Fill in the blanks with correct words.

A bundle of axons enclosed in a tubular sheath is called ________

Q. The myelin sheath around axon is formed by:

1. Nodes of ranvier
2. Schwann cells
3. Both b and c
4. Synaptic knob

Q. Node of Ranvier occurs where

1. nerve is covered with myelin sheath
2. neurilemma is discontinuous
3. neurilemma and myelin sheath are discontinuous
4. myelin sheath is discontinuous

Q. Myelin sheath is produced by :

1. Schwann cells and oligodendrocytes
2. astrocytes and Schwann cells
3. oligodendrocytes and osteoclasts
4. osteoclasts and astrocytes

Q. Which of the following statements is true?

1. Nissl's granules are found in muscles fibres
2. Non - myelinated nerve fibres do not possess nodes of Ranvier.
3. Non - myelinated nerve fibres are completely enclosed by myelin sheath.
4. Saltatory conduction is seen in non - myelinated nerve fibres

Q. In the central nervous system, myelinated parts of the neuron form the ___, while the non-myelinated parts of the cells form the ___.

1. Grey matter, white matter
2. White matter, grey matter
3. Yellow matter, white matter
4. Red matter, yellow matter

Q. A living connecting link which provides evidence for organic evolution is ___________.

1. Duck bill platypus between reptiles and mammals
2. Sphenodon between reptiles and birds
3. Archaeopteryx between reptiles and mammals
4. Lungfish between pisces and reptiles

Q. Which of the following parts of a neuron is covered by fatty sheath?

1. Axon
2. Cyton
3. Dendrite
4. Node of Ranvier

Q. Bipolar nerve cells are present in–

1. Skin tactile corpuscles
2. Spinal cord
3. Retina of eye
4. All the above

Q. What is true about unmyelinated nerve fiber?

1. Not enclosed by both Schwann cells and a myelin sheath.
2. Enclosed by a Schwann cell that does not form a myelin sheath.
3. Not enclosed by a Schwann cell but enclosed by a myelin sheath.
4. Not found in the autonomous and the somatic neural system.

Q. Where can you find nodes of Ranvier?

1. on an axon
2. in the cell body
3. both a and c
4. on a dendrite

Q.

The junction between the two nerve cells is known as

1. synapse

2. node

3. isthmus

4. synaptic buttons

Q. Node of ranvier is the place where

1. myelin sheath and neurilemma are discontinuous
2. axolemma is absent
3. axolemma is discontinuous
4. myelin sheath is discontinuous

Q. The cells involved in forming myelin sheath neurons of CNS are

1. Oligodendrocytes
2. Neurolemmocytes
3. Schwann cells
4. Astrocytes

Q.

Name the types of nerves based on impulses they conduct.

Q. Which of the following help increase speed of conduction through nerve fibres?

1. Having thicker nerve fibres
2. Myelination around nerve fibres
3. Having unmyelinated nerve fibres.
4. Having impulses jump from one node to another

Q.

Which one of the following is a marine fish?

1. Rohu

2. Catla

3. Hilsa

4. Common carp

Q.

how does the tapetal cellsbecome bi-nucleated?

Q. During development, which portion of the brain-the grey or the white matter-enlarges more rapidly?

Q. Assertion : Reason:

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. Medullated nerve fibre in axon is covered by

1. Medullary sheath
2. Neurolemma
3. Mitochondria
4. Both A and B

Q. Where are cortical neurons found ?

Q.

Match the following columns.

Column 1	Column 2
Neurotransmitter	Myelinated sheath
Insulating sheath	Acetylcholine
Nodes of Ranvier	Neurolemma
Neurofibrils	Cyton

Q.

Where can myelinated nerve fibres be seen?