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 zoology animal diversity - i (inverterbrate phyla) structure of earthworm earthworm - morphology, integumentary system , respiration and nervous system adaptations
Which of the following statements is incorrect about the nervous system earthworm?

  1. Nervous system is basically represented by ganglia arranged on ventral nerve cord

  2. In 3rd and 4th segment, the nerve cord bifurcates and joins the cerebral ganglia dorsally to form a nerve ring.

  3. The cerebral ganglia along with other nerves in the ring integrate sensory input as well as command muscular responses of the body

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

The nervous system of earthworm consists of cerebral ganglia or bilobed brain present dorsally, sub pharygeal ganglia, circum pharyngial ganglia and ventral nerve cord. 

So, the correct answer is 'Nervous system is basically represented by ganglia arranged on ventral nerve cord'

Multiple choice zoology animal diversity - i (inverterbrate phyla) structure of earthworm earthworm - morphology, integumentary system , respiration and nervous system adaptations

Read the given statements and select the incorrect one.

  1. In Hydra, all neurons are similar and join to form a nerve net.

  2. In Earthworms, the nervous system consists of a dorsal nerve cord, paired ganglia, and segmental nerves.

  3. Brain is present in insects

  4. Planaria has two nerve cords that join to form rudimentary brain
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The nervous system of an earthworm consists of a ventral nerve cord (not dorsal), paired ganglia, and segmental nerves. Therefore, the statement in option B is incorrect.

Multiple choice biology sensory organs of humans - sense organs ear : the organ of hearing and equilibrium ear and its function ear

Following is a list of the events (in a random order) that lead to the formation of an auditory impulse.
(i) Vibration is transferred from the malleus to the incus to the stapes.
(ii) Basilar membrane moves up and down.
(iii) Nerve impulse is transmitted in cochlear nerve to auditory cortex of brain for impulse analysis and recognitions.
(iv) Sound waves pass through ear canal.
(v) Stereocilia of hair cells of organ of Corti rub against tectorial membrane.
(vi) Sound waves cause ear drum to vibrate.
(vii) Nerve impulse is generated.
(viii) Vibrations move from fluid of vestibular canal to the fluid of tympanic canal.
(viii) Vibrations move from fluid of vestibular canal to the fluid of tympanic canal.
(ix) Membrane at oval window vibrates.
Which of the following options represents these events in a correct order?

  1. (iv), (vi), (i), (ix), (viii), (ii), (v), (vii), (iii)

  2. (i), (ii), (iii), (iv), (v), (vi), (vii), (viii), (ix)

  3. (ix), (viii), (vii), (vi), (v), (iv), (iii), (ii), (i)

  4. (iv), (vi), (i), (viii), (ix), (ii), (v), (vii), (iii)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The ear not only detects sound but also notes its direction, judges its loudness and determines is pitch.Auditory impulse form through different steps:

1. Sound waves are collected by the pinna and directed inward through external auditory canal.
2. Here they strike the tympanic membrane. The latter begins to vibrate at the same frequency as that of the sound waves.
3. From tympanic membrane, the vibration transmitted across the tympanic cavity by the ear ossicles.The outer ossicles called malleus, inner called stapes, middle ossicles called incus.
4. Stapes is fit into oval window which vibrates. The ear ossicles transmit the vibrations from tympanic membrane to the internal ear and also amplify them 20 times.
5.  Increase in force is important because the sound waves are transmitted from air to a fluid medium.
6. From here, the vibrations are transferred to the basilar membrane and the perilymph in the scala tympani, and are finally dissipated into the air of the middle ear as vibrations of the round window membrane.
7. Vibrations of the floor make the "sensory hair" of receptor cells in the organ of corti move in the overlying gelatinous membrane, and get distorted.
8. This stimulation causes  depolarisation of the receptor cells and initiation of receptor( action) potential in the fibres of the auditory nerve.
9. The latter carries the impulses to the cerebral cortex, which interprets the impulses as sound.
So, the correct answer is '(iv), (vi),(i), (ix), (viii), (ii), (v), (vii), (iii)'.

Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans

Assertion: In man, only peripheral nervous system is present.

Reason: The peripheral nervous system includes nerves coursing between the central nervous system and different parts of the body.

  1. If both the assertion and the reason are true and the reason is the correct explanation of the assertion

  2. If both the assertion and the reason are true and the reason is not the correct explanation of the assertion

  3. If the assertion is true and the reason is false

  4. If both the assertion and the reason is false

  5. If the assertion is false but the reason is true
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The nervous system of human comprises of Central Nervous System - comprises of brain and spinal cord. Peripheral Nervous System - comprises of nerves present between brain and body parts.

Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans

Which of the following is correct?

  1. Spinal cord is a part of central nervous system.

  2. Nerves are continuous fibres.

  3. Reflexes are not controlled by nerves.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The spinal cord is a part of the central nervous system. The most important structure between our body and our brain is the spinal cord. It extends from the foramen magnum, where it is continuous with the medulla to the level of the first or second lumbar vertebrae. It is a vital link not only from the brain to the body but also from the body to the brain. The spinal cord is 40 to 50 cm long and 1 cm to 1.5 cm in diameter. 

Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans

Central nervous system consists of

  1. Brain

  2. Spinal cord

  3. Nerves and ganglia

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • The central nervous system (CNS) is the processing center for the nervous system. The two main organs of the CNS are the brain and spinal cord. The brain processes and interprets the sensory information sent from the spinal cord. Both the brain and spinal cord are protected by three layers of connective tissue, called meninges.
  • Within the central nervous system is a system of hollow cavities, called 'ventricles'. The network of linked cavities in the brain (cerebral ventricles) is continuous with the central canal of the spinal cord. The ventricles are filled with cerebrospinal fluid, which is produced by specialized epithelium located within the ventricles, called the choroid plexus. 
  • Cerebrospinal fluid surrounds, cushions and protects the brain and spinal cord from trauma. It also assists in the circulation of nutrients to the brain.
Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans

Identify the organ which is the part of the CNS. It is thick and resembles a cream coloured rope which is made up of nerves that relay messages. 

  1. Backbone

  2. Brain

  3. Spinal cord

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

  • The brain and spinal cord are the two major parts of the CNS. The brain forms the largest portion of the CNS. 
  • The brain resembles a cream-colored rope made up of nerves that that relay messages.
  • The spinal cord stretches from the medulla oblongata at the base of the brain to the lower back and is housed in a tunnel made by the vertebrae bones of the spinal column. 
  • The spinal cord works a bit like a telephone switchboard operator, helping the brain communicate with different parts of the body and vice versa. 

Therefore, the correct answer is option B.

Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans

The outer membrane that covers brain is

  1. Myelin Sheath

  2. Duramater

  3. Arachnoid membrane

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

The membrane which covers the brain and the spinal cord is called as the meninges. There are three layers of the meninges. The outermost is the Dura mater, middle one is the arachnoid mater and the innermost is the pia mater. Dura mater is the tough membrane which is present in the outermost region. The three meninges provide protection to the brain from shock and injury. 

Thus, the correct answer is option B. 

Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans

White matter consists of

  1. Nerve fibres with myelinated sheath

  2. Nerve fibres without myelinated sheath

  3. Scattered areolar tissue

  4. Nerve fibre with blood vessels
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

White matter is a component of the central nervous system, in the brain and spinal cord. The white matter is placed on the grey matter in the brain while it lies outer to the grey matter in the spinal chord. It consists mostly of glial cells and myelinated axons that transmit signals from one region of the cerebrum to another and between the cerebrum and lower brain centres.

Thus, the correct answer is option A.

Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans

Afferent nerve fibre carries impulses from

  1. Effector to central nervous system

  2. Receptor to central nervous system

  3. Central nervous system to muscles

  4. Central nervous system to receptors
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Afferent (sensory) nerve fibers carry impulses from sensory receptors toward the central nervous system. Efferent (motor) fibers carry impulses away from the CNS to effectors.

Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans

The term "grey matter" refers to

  1. neurons that are unmyelinated

  2. axons that are myelinated

  3. dendrites that are myelinated

  4. neurons that are myelinated
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The grey matter is mainly composed of neuronal cell bodies and unmyelinated axons. In the grey matter, these axons are mainly unmyelinated, meaning they are not covered by a whitish-coloured, fatty protein called myelin. The grey matter serves to process information in the brain.

So, the correct answer is 'neurons that are unmyelinated'.
Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans
The central nervous system consists of the brain and spinal cord.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The central nervous system is responsible for integrating sensory information and responding accordingly. It consists of two main components:
  1. The spinal cord serves as a conduit for signals between the brain and the rest of the body. It also controls simple musculoskeletal reflexes without input from the brain.
  2. The brain is responsible for integrating sensory information and coordinating body function, both consciously and unconsciously. 
Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans

The largest number of neurons are found in

  1. Brain

  2. Retina

  3. Spinal cord

  4. Tongue
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Retina forms the innermost layer of eyeball and mainly contains rods and cones, the photoreceptors, along with nerve fibres. 

Tongue is a muscular organ, composed of skeletal muscles, to help change its shape and support the movement. Main function of central nervous system (brain and spinal cord) is to integrate the sensory inputs from internal and external environment as received by sensory neurons and process and finally transmit the nerve impulses to effectors (muscles and glands). Thus, being the centre of processing information, brain has maximum number of neurons followed by spinal cord. 
Therefore, the correct answer is option A.

Multiple choice biology nervous system of man human nervous system the structure of brain the human brain

Crura cerebri consist of

  1. Longitudinal bands of nerve fibres

  2. Transverse bands of nerve fibres

  3. Oblique bands of nerve fibres

  4. Bands of nerve fibres that cross each other
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The midbrain is a small and contracted region of the brain. The anterior region of the midbrain is made up of two longitudinal bands of myelinated nerve fibres called the cerebral peduncles or crus cerebri or crura cerebri. The posterior part of the midbrain is made up of projected optic lobes called the colliculi.

Hence, the correct answer is 'Longitudinal bands of nerve fibres'

Multiple choice biology coordination generation and conduction of nerve impulse generation of nerve impulse neurons and synapses

Neurotransmitters are released at the synapse by ___________

  1. Tips of Dendrites

  2. Synaptic Knobs

  3. Organelles of Cyton

  4. Myelin sheath of Axon
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Synaptic knobs, or axon terminals, contain synaptic vesicles filled with neurotransmitters that fuse with the presynaptic membrane to release their contents into the synaptic cleft upon action potential arrival.