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

Ejaculation is a function of the

  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 controlled by the sympathetic nervous system, which coordinates the emission of semen and propels it through the urethra. The somatic nervous system controls voluntary movements, and the sensory nervous system transmits sensory information.

Multiple choice

Which star shaped glial cell(s) is/are present in the central nervous system?

  1. Neuroglia

  2. Dendrite

  3. Axon

  4. Pons

  5. Astrocytes
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Astrocytes are the star shaped glial cells that are the majority cell type in the central nervous system. They have a multitude of functions including regulation of the ionic milieu in the intercellular space, uptake and/or breakdown of some neurotransmitters and formation of the blood brain barrier.

Multiple choice

Which of the following proteins is/are required for the growth, development and survival of neurons?

  1. GABA

  2. Neurotrophins

  3. Neuromodulators

  4. Acetylcholine

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

Neurotrophins are small proteins secreted in the nervous system at extremely low concentration. Low levels of a neurotrophin are needed to keep nerve cells alive. However, in some cases, presence of a neurotrophin can have the opposite effect by initiating cell death. During the development of nervous system, the level of neurotrophins can control the unwanted nerve cells.

Multiple choice

The largest division of the trigeminal nerve is

  1. ophthalmic nerve

  2. maxillary nerve

  3. mandibular nerve

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

Mandibular nerve is the largest of the three divisions of the trigeminal nerve, consists of two roots, a large sensory root and a small motor root. The ophthalmic nerve is the smallest of the three and is a sensory nerve.

Multiple choice

Nasociliary nerve enters the orbit through

  1. the superior orbital fissure

  2. the inferior orbital fissure

  3. foramen rotundum

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

Nasociliary nerve is the 3rd main branch of the ophthalmic division. It enters the orbit through the superior orbital fissure. The branches of this nerve are divided into those arising in the orbit, in the nasal cavity and on the face.

Multiple choice

There are particular centres and circuits in animals' nervous system which produce fixed and stereotyped responses to evidence stimuli. What is this mechanism called?

  1. Effector mechanism

  2. Innate releasing mechanism

  3. Concept of motivation

  4. Sensory perceptual mechanism

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

An innate releasing mechanism is a hypothetical innate system within an animal that responds to a stimulus in the environment to produce a pre-programmed stereotyped behavior or fixed action pattern. 

Multiple choice

The homeostatic regulation of an animal involves three basic steps, viz. detection of changes in the environment, evaluation of changes and adjustment or response to the changes respectively. Which of the following are the components that are sequentially involved in such a regulation?

  1. Spinal cord, brain, effectors

  2. Receptors, CNS, effectors

  3. Receptors, sensory nerves, effectors

  4. Receptors, brain, effectors

  5. Spinal cord, sense organs
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the stimulus exceeds a threshold value,  the receptors release an impulse to the neuron connected to it and that sensory neuron transmits the impulse to the central nervous system, i.e. brain or spinal cord. They evaluate and analyze the impulse and send it to specific effectors in muscle, which ultimately respond to the stimulus by contracting specific organ or organs.

Multiple choice

The fourth cranial nerve is distributed in the areas of

The third and fourth cranial nerves having same origin, i.e. floor of mid brain but differ in distribution and function.

  1. eye muscle pupil and ciliary muscle

  2. superior oblique eye muscle

  3. vestibule and cochlea

  4. retina

  5. lateral rectus eye muscle
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Trochlear, the fourth cranial nerve, having distribution at superior oblique eye muscle helps in eyeball movement.