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

Neuroepithelial type of sensory receptors are present in which of the following systems?

  1. Visual

  2. Auditory

  3. Gustatory

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

A neuroepithelial receptor is a neuron with a soma situated near a sensory surface and an axon, which conveys sensory signals into the CNS to synapse on second order neurons. This is an evolutionarily primitive arrangement and the only example in man is the sensory neuron of the olfactory epithelium.

Multiple choice

The membrane potential in a nerve cell during resting stage denotes ______.

  1. both sides negative

  2. negative inside the cell with respect to outside

  3. positive inside the cell with respect to outside

  4. both sides positive
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Membrane potentials across cell membranes are a function of the electrolyte concentrations in the intracellular and extracellular solutions and of the selective permeabilities of the ions. Membrane potential in a nerve cell during resting stage is -60 mV, which means interior of the cell is negative with respect to the exterior. During depolarisation of nerve cells, the inside becomes positive due to the influx of Na+ ions.

Multiple choice

A person entering an empty room suddenly finds a snake right in front of him on opening the door. Which one of the following is likely to happen in his neuro-hormonal control system?

  1. SNS is activated releasing epinephrine and norepinephrine from adrenal medulla.

  2. Neurotransmitters diffuse rapidly across the cleft and transmit a nerve impulse.

  3. Hypothalamus activates the parasympathetic division of brain.

  4. Sympathetic nervous system is activated releasing epinephrine and norepinephrine from adrenal cortex.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Epinephrine and norepinephrine are secreted by adrenal medulla in response to stress of any kind and during emergency situations. Hence, they are also called emergency hormones of flight or fight.

Multiple choice

Find the odd one out.

  1. GABA

  2. Acetylcholine

  3. Histidine

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

Histidine is the only amino acid that does not act as neurotransmitter.

Multiple choice

The resting membrane potential of neuron is maintained by which of the following? A. Differences in K+ and Na+ ion concentrations B. Sodium efflux and Potassium influx C. Higher permeability to sodium ions D. Sodium-potassium pumps that help to maintain the proper distribution of sodium and potassium

  1. A, D

  2. A, C

  3. B, C

  4. C, D
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The resting membrane potential is maintained by differences in both ion concentrations and electron gradient, which is established by the proper distribution of sodium and potassium through sodium-potassium ion channel.

Multiple choice

Which of the following statements regarding the innervation of the human heart is false?

  1. Afferent fibres carrying pain sensation run to the spinal cord.

  2. During rest, the vagal tone is recessive.

  3. Postganglionic fibres descend to the heart and form two plexuses.

  4. The effects of autonomic nervous system on coronary artery and blood flow are reciprocal.

  5. Preganglionic sympathetic fibres ascend from the upper five thoracic segments of the spinal cord.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is incorrect as during rest, the vagal tone is dominant. 

Multiple choice

The receptors found in the muscles, tendons and joints are

  1. teloreceptors

  2. proprioreceptors

  3. interorereceptors

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

The receptors found in the muscles, tendons and joints are propriorecpetors. These are stretch recpetors. They supply information about the so called kinesthetic sense of equilibrium and orientation. They act like pressure gauges and are responsible for maintenance of body posture. 

Multiple choice

Damage to vagus nerve may lead to which of the following?

  1. Gastroparesis

  2. Gastroptosis

  3. Achlorhydria

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

A damaged vagus nerve cannot send signals to the stomach muscles. This may cause food to remain in the stomach longer, rather than move normally into the small intestine to be digested. This condition is called gastroparesis or paralysis of stomach.

Multiple choice

Match column I with column II.

 
Column I Column II
1. Autonomic nervous system i. Forebrain
2. Control centre of thinking ii. Brain and spinal cord
3. Central nervous system iii. Sympathetic and asympathetic nervous systems
4. Blood pressure is controlled by iv. Cerebellum
5. Activities like riding a bicycle are controlled by v. Medulla

  1. 1 - iii, 2 - i, 3 - ii, 4 - v, 5 - iv

  2. 1 - iv, 2 - iii, 3 - i, 4 - v, 5 - ii

  3. 1 - iii, 2 - i, 3 - v, 4 - ii, 5 - iv

  4. 1 - ii, 2 - iii, 3 - v, 4 - i, 5 - iv
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

2,4-D is a synthetic auxin, which is a class of plant hormones.

Multiple choice

The action potential in the nerve impulse results from

  1. decrease in -ve charge inside the nerve fibre

  2. increase in +ve charge outside the nerve fibre

  3. opening of voltage gated Na+ channels

  4. activation of Na-K pump
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Action potential is a short-lived fluctuation in membrane potential of the plasma membrane, which is caused by the opening of the voltage gated ion channels that actively moves the ions across the membrane causing the potential difference.

Multiple choice

What happens during reflex actions?

  1. Sensory impulses are converted into motor impulses in the brain.

  2. Sensory impulses are converted into motor impulses in the spinal cord.

  3. Motor impulses are converted to sensory impulses in the brain.

  4. Motor impulses are converted into sensory impulses in the spinal cord.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During reflex action, sensory impulses are converted into motor impulses in the spinal cord.

Multiple choice

Proprioceptors are found in

  1. skin

  2. eye

  3. muscles tendons and joints

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

Proprioceptors are found in muscle tendons and joints. These sense the movements and positions of muscles and appendages relative to each other and also to the spatial body as a whole.

Multiple choice

Which one is the correct representation of a reflex arc?

  1. Receptor - Sensory neuron - Motor neuron - Inter neuron - Effector organ

  2. Sensory neuron - receptor - Motor neuron - Inter neuron - Effector organ

  3. Receptor - Sensory neuron - Inter neuron - Motor neuron - Effector organ

  4. Receptor - Sensory neuron - Motor neuron
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Stimulus are received by receptors which passes it to sensory neuron that conveys impulses to spinal cord. Impulses are passed to motor neurons via inter-neurons and then, to the effector organ that responds to the impulses received.