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

Transformation of mechanical to neural signals takes place

  1. at the base of the outer hair cells

  2. at potassium ion channels in stereocilia

  3. between the oval and round windows

  4. in the scala tympani

  5. in the scala vestibuli

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

Movement of the cilia opens potassium channels. The influx of potassium causes a subsequent influx of calcium and a receptor potential that can cause an action potential in the afferent dendrites.

Multiple choice

Neuropeptides are small protein molecules used by neurons to communicate with each other. They are present in synaptic terminals because

  1. they are synthesized in the terminal

  2. they are carried by fast axonal transport

  3. they are carried by diffusion

  4. they are carried by slow axonal transport

  5. they are taken-up from the extracellular space

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

Neuropeptides are neuronal signaling molecules. They are synthesized in the cell body and are processed in vesicles that are transported to axon terminals along microtubules via fast axonal transport.

Multiple choice

Nerve transmission is a

  1. biological process

  2. mechanical process

  3. physical process

  4. chemical process
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Nerve conduction is an electrochemical process, which means that it uses electricity made with chemical molecules.

Multiple choice

'Dendrites' are found in

  1. striated muscles

  2. non-striated muscles

  3. neurons

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

Ans - 3

The short branched fibre of neuron, which receives nerve impulses.

Multiple choice

Which among the following is the nerve of the taste?

  1. V cranial nerve

  2. V1 cranial nerve

  3. V111 cranial nerve

  4. 1X cranial nerve

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

The glossopharyngeal nerve (IX cranial nerve) is responsible for taste sensation from the posterior one-third of the tongue. The V (trigeminal) nerve handles general sensation, and the VIII (vestibulocochlear) nerve handles hearing and balance.

Multiple choice

A nerve fibre is depolarized when it acquires

  1. a negative charge in the intracellular fluid and positive charge outside

  2. a positive charge in the intracellular fluid and negative charge outside

  3. positive charge on both sides

  4. negative charge on both sides
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Depolarization occurs when the membrane potential becomes less negative (or more positive) inside the cell relative to the outside, typically due to an influx of sodium ions.

Multiple choice

The 3rd, 6th and 11th cranial nerves respectively are

  1. optic, facial and spinal nerves

  2. oculomotor, trigeminal and spinal

  3. trigeminal, abducens and vagus

  4. oculomotor, abducens and spinal
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The 3rd cranial nerve is the oculomotor nerve, the 6th is the abducens nerve, and the 11th is the spinal accessory nerve. Option D correctly identifies these.

Multiple choice

The autonomous nerve system has control over :

  1. Reflex action

  2. Skeletal muscle

  3. Sense organs

  4. Internal organs
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The autonomic nervous system (ANS) regulates the functions of our internal organs (the viscera) such as the heart, stomach and intestines. The ANS is part of the peripheral nervous system and it also controls some of the muscles within the body.

Multiple choice

Pacinian corpuscles occurring in the skin of certain parts of the body in mammals, are

  1. Pain receptors

  2. Tactile receptors

  3. Gland-type

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

Pacinian corpuscles are  tactile receptors (tangoreceptors) occur in deeper layer of skin dermis of palms, sole, fingers, external genitals, nipples, arms , neck, joints ect. These are oval, spherical or irregularly coiled and very characteristic in structure. All tactile receptors are involved in deterction of vibration, although different receptors detect different receptors detect different frequencies of vibration. (30 - 800 cycles per second by pacinian corpuscles. 

Multiple choice

Myelin sheath covers which of the following?

  1. muscle fibre

  2. nerve fibre

  3. collagen fibre

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

Myelin sheath is a layer convering vertebrate nerve fibre. It is produced by flattened cells called Schwann's cells. Myelin serves as insulating material and causes slatatory conduction of impulses.  

Multiple choice

Which of the following is motor nerve?

  1. Vagus

  2. Abducens

  3. Olfactory

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

Abducens nerves are motor nerves which arise form ventral part of medulla oblongata, pass through respective Gasserian ganglia and innervate the posterior rectus muscle of eyes.
Facial nerves are mixed nerves arising form lateral part of medulla oblongata.
Vagus nerves are mixed nerves arising form lateral aspects of medulla oblongata.
Olfactory nerves are purely sensory nerves which transmit sensory impulses form the neurosensory epithelium of nasals chambers to olfactory lobes of brain. 

Multiple choice

The junction of an axon and dendrite is called :

  1. Relay

  2. Synapse

  3. Cytone

  4. Conduction Zone
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The junction between the terminations of two neurons is called a synapse. It is the the junction between the axon of one neuron and the dendrite of another neuron.