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

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.

Multiple choice

Ejaculation is a function of

  1. sensory nervous system

  2. somatic nervous system

  3. sympathetic nervous system

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ejaculation is a function of sympathetic nervous system.

Multiple choice

Peripheral nervous system consists of:

  1. cranial nerves only

  2. spinal nerves only

  3. both cranial and spinal nerves

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Peripheral nervous system consists of spinal nerves only.The peripheral nervous system (PNS) is the part of the nervous system that consists of the nerves and ganglia outside of the brain and spinal cord.

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 depolarisation, permeability of neuron increases towards Na+, which changes the electrochemical gradient, which in turn produces a further rise in the membrane potential. This then causes more channels to open, producing a greater electric current across the cell membrane, and so on.

Multiple choice

The largest cranial nerve in human beings is the

  1. optic nerve

  2. facial nerve

  3. trigeminal nerve

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

The largest cranial nerve in human beings is the trigeminal nerve. It has three major branches: the ophthalmic nerve (V1), the maxillary nerve (V2), and the mandibular nerve (V3).

Multiple choice

Which is the longest cranial nerve?

  1. Trochlear

  2. Trigeminal

  3. Vagus

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

This option is correct because vagus has the maximum number of branches and it is also known as wondering nerve.