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

Which of the following laws is/are associated with the fact that anterior spinal nerve roots contain only motor fibres and posterior roots contain only sensory fibres?

  1. Magendie's law

  2. Bell's law

  3. Both (1) and (2)

  4. None of these

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

This law was given by both Bell and Magendie.  The anterior spinal nerve roots contain only motor fibers and posterior roots only sensory fibers and that nerve impulses are conducted in only one direction in each case.

Multiple choice

The systems that simulate intelligence by attempting to reproduce the types of physical connections that occur in animal brains are called as ______________.

  1. expert systems

  2. robotics

  3. neural networks

  4. real-time processing systems

  5. batch processing systems
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The systems that simulate intelligence by attempting to reproduce the types of physical connections that occur in animal brains is called as neural networks.

Multiple choice

Adrenaline directly affects ______.

  1. islet of langerhans

  2. sinoatrial node

  3. oxyntic cells of stomach

  4. dorsal root ganglia of spinal cord
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Adrenaline (epinephrine) directly stimulates the sinoatrial (SA) node, the heart's natural pacemaker, increasing heart rate and contractility. This is part of the 'fight or flight' response. It does not directly affect the islets of Langerhans (pancreatic hormone-producing cells), oxyntic cells (stomach acid-producing), or dorsal root ganglia (sensory nerve clusters).

Multiple choice

The neurotransmitters are released by

  1. axon hillock

  2. nodes of Ranvier

  3. soma

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

The terminal buttons are the small knobs at the end of an axon that release chemicals called neurotransmitters. The terminal buttons form the presynaptic neuron of the synapse.

Multiple choice

Fat containing cells enclosing the axon of some neurons

  1. are the sites of neurotransmitters production

  2. receive messages from other neurons

  3. slow down the rate of transmission

  4. speed up the rate of transmission
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes, the fat containing mylein sheath cells can speed up the rate of transmission across the nerve fibre.

Multiple choice

The perineurium is the connective tissue layer

  1. surrounding an entire nerve

  2. surrounding fascicles of axons in the CNS

  3. surrounding individual axons in the PNS

  4. surrounding fascicles of axons in the PNS
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The perineurium is composed of connective tissue. It is a protective sheath surrounding the fascicles of axons in the PNS.

Multiple choice

In mammals, the entry of ions in the neural cell is governed by ___________.

  1. dendrites

  2. channels

  3. myelin sheaths

  4. meninges

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

The channels are made up of glycoproteins. The ions cross through their channels by electrical potential. Through the channels, the ions which are mainly carried in physiological conditions are sodium, potassium, calcium and chlorine.

Multiple choice

Which among the following statements regarding the sympathetic nervous system is incorrect?

  1. Sympathetic nerves originates inside the vertebral column.

  2. The sympathetic nervous system is responsible for up and down-regulating in many homeostatic mechanisms of the body.

  3. The sympathetic nervous system mobilises the body in a fight-or-flight response.

  4. Sympathetic nervous system stimulation causes vasodailation of most blood vessels in the body.

  5. Sympathetic nervous system stimulates gut motility and urinary system output and function.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sympathetic nervous system stimulation causes vasoconstriction of most blood vessels, including those of the skeletal muscle.