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

What is the inter-neuronal junction called?

  1. Synapses

  2. Nodes of Ranvier

  3. Schwann cells

  4. Nissl bodies

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The interneuronal junction are called synapses. A synapse is a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.

Multiple choice

Which of the following cranial nerves controls sound production?

  1. Facial

  2. Trochlear

  3. Vagus

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

The vagus nerve (CN X) controls the larynx and is essential for speech and sound production. It innervates the vocal cords via the recurrent laryngeal nerve. The facial nerve (CN VII) controls facial expression, trochlear (CN IV) controls superior oblique eye muscle, and hypoglossal (CN XII) controls tongue movement.

Multiple choice

The largest cranial nerve in human being is

  1. optic

  2. facial

  3. trigeminal

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

The trigeminal nerve (CN V) is the largest cranial nerve by diameter and root size. It has three major divisions: ophthalmic, maxillary, and mandibular, supplying sensation to most of the face and motor function to muscles of mastication. Optic (CN II) is actually the largest by NUMBER of axons (over 1 million), but trigeminal is largest by physical size.

Multiple choice

During depolarisation, permeability of neuron increases towards

  1. H+

  2. Na+

  3. Ag+

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

During depolarization, voltage-gated sodium (Na+) channels open, allowing Na+ ions to rush INTO the neuron down their concentration gradient. This rapid influx of positive charge makes the membrane potential less negative (more positive), creating the rising phase of the action potential. Potassium (K+) efflux causes repolarization, not depolarization.

Multiple choice

After a car accident that produced trauma to a 40-years-old woman’s skull, she complained of double vision. The doctor would need to consider which of the following cranial nerves in his diagnosis?

  1. Optic (II), oculomotor (III) and trigeminal (V)

  2. Oculomotor (III), trochlear (IV) and trigeminal (V)

  3. Oculomotor (III), trochlear (IV) and abducens (VI)

  4. Oculomotor (III), trigeminal (V) and abducens (VI)

  5. Oculomotor (III), trigeminal (V) and facial (VII)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Yes, it is correct. The oculomotor nerve (III) supplies four of the six extraocular muscles.

Multiple choice

The trochlear nerve is the only cranial nerve that exits from the dorsal side of the brainstem. Which of the following muscles would be affected if the nerve is inadvertently damaged?

  1. Superior oblique muscle

  2. The lateral rectus muscle

  3. Superior tarsal muscle

  4. Sphincter pupillae muscle

  5. Dilator pupillae muscle
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yes, it is correct. The trochlear nerve (IV) is the only cranial nerve to exit from the posterior surface of the brainstem. It innervates the superior oblique muscle.

Multiple choice

Which of the following types of sensory cell is used in auditory and vestibular systems of the human body?

  1. Stria vascularis cell

  2. Neuroepithelial hair cell

  3. Ependymal cell

  4. Perilymph cell

  5. Endolymph cell
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Yes, it is correct. The neuroepithelial hair cell is used by both the auditory system (in the organ of Corti) and in the vestibular system (in the crista ampullaris and the macula). The stereocilia on these cells are deflected by fluid motion and produce action potentials, which are relayed to specific bipolar neurons.