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 statements regarding sympathetic nervous system is incorrect?

  1. Sympathetic nervous system stimulates gut motility and urinary system output and function.

  2. Sympathetic nervous system stimulation causes vasodilation of most blood vessels in the body.

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

  4. Sympathetic nervous system is responsible for up and down regulating of many homeostatic mechanisms of the body.

  5. Sympathetic nerves originate inside the vertebral column.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

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

Multiple choice

Among the following biomolecules, ___________ is a neurotransmitter.

  1. Abamectin

  2. Abietic acid

  3. Acetic acid

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

The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system (PNS) and central nervous system (CNS) in many organisms including humans. Acetylcholine is one of many neurotransmitters in the autonomic nervous system (ANS) and the only neurotransmitter used in the motor division of the somatic nervous system.

Multiple choice

Nerves are wires that are distributed all over the human body. Which of the following statements is/are correct about nerves?

a. There are mainly two types of nerves. b. Cranial nerves connect all parts of the body to the brain. c. Visceral nerves connect the internal organs of the body to the spinal cord, though some also connect to brain.

  1. Only a

  2. Both a and b

  3. Only b

  4. Both b and c

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

This is the correct option.

Multiple choice

Which of the following statements is correct about axon?

  1. Axon picks up the nerve impulses from receptors.

  2. Axon is the junction through which impulses are passed through to another neuron.

  3. Axon is made of fats and proteins.

  4. Axon is the shortest fibre on the cell body of a neuron.

  5. Axon is the longest fibre on the cell body of a neuron.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct option. Axon is the longest fibre on the cell body of a neuron.

Multiple choice

An inhibitory neurotransmitter decreases the electrochemical activity of neurons. Among the following, ___________ is a chief inhibitory neurotransmitter in mammals.

  1. gadopentetic acid

  2. galantamine

  3. galactose

  4. γ-aminobutyric acid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

γ-Aminobutyric acid is the chief inhibitory neurotransmitter in the mammalian central nervous system. It plays a role in regulating neuronal excitability throughout the nervous system.

Multiple choice

Myelin sheath is the insulating envelope surrounding the nerve fibre and facilitates the transmission of nerve impulses. Which of the following amino acids helps in the maintenance of the myelin sheaths?

  1. Cysteine

  2. Histidine

  3. Glutamine

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

Histidine is known to be vital in the maintenance of the myelin sheaths surrounding nerves, particularly the auditory nerve and is used to treat some forms of hearing disability.

Multiple choice

Blocking of acetylcholine receptors at the postsynaptic neuromuscular junction by circulating antibodies causes

  1. myasthenia gravis

  2. polymyalgia rheumatica

  3. microscopic polyangiitis

  4. Behcet's syndrome
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Myasthenia gravis or muscle weakness is caused by circulating antibodies that block acetylcholine receptors at the postsynaptic neuromuscular junction. It inhibits the excitatory effects of neurotransmitter acetylcholine on nicotinic receptors at neuromuscular junctions.

Multiple choice

Which of the following statements regarding the coordination of activities in sponges is INCORRECT?

  1. Glass sponges rapidly transmit electrical impulses through all parts of the syncytium.

  2. Myocytes are thought to be responsible for transmitting signals between different parts of the body.

  3. Adult sponges are well equipped with neurons.

  4. Some species can contract the osculum independently of the rest of the body.

  5. Sponges may also contract in order to reduce the area that is vulnerable to attack by predators.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Adult sponges lack neurons or any other kind of nervous tissue. However most species have the ability to perform movements that are coordinated all over their bodies, mainly contractions of the pinacocytes, squeezing the water channels and thus expelling excess sediment and other substances that may cause blockages.