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

State of complete inexcitability between polarisation and repolarisation is

  1. Refractory period

  2. Synaptic delay

  3. Action potential

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

The refractory period is the time during which a neuron is incapable of generating another action potential, occurring after depolarization and during repolarization.

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

Cell bodies of motor nerve fibres occur in

  1. Dorsal root of spinal nerve

  2. Dorsal horn of spinal cord

  3. Ventro-lateral horn of spinal cord

  4. Ventral root of spinal cord
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The cell bodies of motor neurons (somatic efferent neurons) are located in the ventral (anterior) horn of the spinal cord gray matter.

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

In resting nerve what is true

  1. 3N$a^+$ are pumped in and 2 $K^+$ pumped out
  2. 3N$a^+$ are pumped out for every 2$K^+$ pumped in

  3. There is no Na-K pump

  4. Na-K pump stops working
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Na+/K+ pump maintains the resting potential by actively transporting 3 Na+ ions out of the cell and 2 K+ ions into the cell for every ATP molecule hydrolyzed.

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

Depolarisation of nerve cell involves

  1. Influx of $K^+$
  2. Influx of N$a^+$
  3. Influx of C$a^{2+}$ and Cl
  4. Efflux of N$a^{2+}$
  5. Efflux of C$a^{2+}$ and Cl
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Depolarization occurs when the resting membrane potential becomes less negative. This is primarily caused by the rapid opening of voltage-gated sodium channels, allowing Na+ to rush into the cell.

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

In resting stage of neuron, diffusion due to concentration gradient will drive

  1. $K^+$ into cell
  2. $K^+$and N$a^+$ out of cell
  3. N$a^+$ into cell
  4. N$a^+$ out of cell
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the resting state, there is a high concentration of Na+ outside the cell and a low concentration inside. Due to the concentration gradient, Na+ ions have a natural tendency to diffuse into the cell, though the membrane is relatively impermeable to them at rest.