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 zoology diversity in living world hemichordata phylum hemichordata chordates and hemichordates

Chorda dorsalis is

  1. Dorsal solid nerve cord

  2. Dorsal hollow nerve cord

  3. Notochord

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

Chorda dorsalis originates from Latin. Chorda literally means 'sting' and dorsum means 'back'. Hence the answer is 'notochord' because it is the spinal column which is present on the dorsal side of an embryo. The notochord is a common aspect of all Chordates.

So, the correct answer is 'Notochord'.

Multiple choice biology life processes in living organism movements in plants coordination in plants tropic and nastic movements in plants

Which cranial nerve is present in Rabbit but absent in frog?

  1. Glossopharyngeal

  2. Hypoglossal

  3. Olfactory

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

The hypoglossal nerve (XII) is a cranial nerve present in mammals, including rabbits, but it is absent in amphibians like frogs. In frogs, the tongue muscles are innervated by spinal nerves rather than a dedicated cranial nerve.

Multiple choice evs the unique world of insects and animals sleeping time animal senses sense organs in animals sense organs in humans

Which of the following receptor classifications could be considered enteroreceptors?

  1. Chemoreceptors

  2. Photoreceptors

  3. Visceroreceptors

  4. Both (a) and (c)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Enteroceptor - any receptor that responds to stimuli inside the body.
  • Chemoreceptors: consists of aortic and carotid bodies. Aortic body detects changes in blood oxygen and carbon dioxide, but not pH, while carotid body detects all three.
  • visceroreceptors group of receptors that includes those located in visceral organs. Their stimulation gives rise to poorly localized and ill-defined sensations or to pain. In hollow visceral organs, they are stimulated principally by excessive contraction or by distention.

Since both chemoreceptors and visceroreceptors respond to stimuli inside the body, these can be categorized under enteroreceptors.

So, the correct answer is 'Both (a) and (c)'.

Multiple choice evs the unique world of insects and animals sleeping time animal senses sense organs in animals sense organs in humans

Which of the following are chemoreceptors?

  1. Taste receptors

  2. Olfactory receptors

  3. Auditory receptors

  4. Both (a) and (b)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chemoreceptors are the receptors that respond to chemicals. Both taste and smell are related to chemical receptors. Therefore, they are chemoreceptors.

So, the correct option is 'Both (a) and (b)'.

Multiple choice evs the unique world of insects and animals sleeping time animal senses sense organs in animals

Organs that helps to detect stimulus from surroundings is called as

  1. Muscles

  2. Sense organs

  3. Blood

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Sense organs are organs of the body which response to external stimuli by conveying impulses to the sensory nervous system.
  • We see with our eyes, we smell with our noses, we listen with our ears, we taste with our tongue, and we touch with our skin. Our brain receives signals from each of these organs and interprets them to give us a sense of what's happening around us.
  • Hence Organs that helps to detect stimulus from surroundings is called as sense organs.
  • So, the correct answer is 'Sense organs'.
Multiple choice biology control and coordination in living organisms control of blood glucose endocrine system and hormone hormones in human reproduction testes and ovary parts of the brain kidney

Vasopressin influences 

  1. Electrolyte efflux

  2. Nerve excitability

  3. Water reabsorption

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Vasopressin, also known as antidiuretic hormone (ADH), is a neurohypophysial hormone which has two primary functions- to retain water in the body and to constrict the blood vessels. Vasopressin regulates the body's retention of water by increasing water reabsorption in the collecting ducts of the kidney nephron.

Multiple choice biology control and co-ordination in plants and animals control of blood glucose hormones in human reproduction testes and ovary

Myelin sheath is covering of

  1. Muscle cells

  2. Axon of neurons

  3. Blood vessels

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

A neuron can be defined as a long cytoplasmic process of the cell body, which transmits the impulse from the cell body to other neurons is termed. The axon is covered by a lipid-rich membrane, called myelin sheath. The myelin sheath is formed by Schwann cells and each Schwann cell covers a part of the axon.
Thus, the correct answer is the option (B), 'Axon of neurons'.

Multiple choice

After presynaptic neurons are depolarized they:

  1. Release a neurotransmitter into the synapse

  2. Trigger an action potential within the synapse

  3. Produce acetylcholine in the cytoplasm

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

When the presynaptic membrane depolarizes, voltage-gated calcium channels open, leading to an influx of calcium which triggers the exocytosis of neurotransmitters into the synaptic cleft.

Multiple choice

Propagation of nerve impulses is the result of local currents causing each part of the neuron:

  1. To remain below threshold potential

  2. To reach threshold potential

  3. To return to resting potential

  4. To remain at resting potential
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Local currents flow from an active region to an adjacent inactive region, causing the membrane potential in the inactive region to rise until it reaches the threshold potential, triggering a new action potential.

Multiple choice

During depolarization:

  1. K+ moves into the axon via facilitated diffusion

  2. K+ moves out of the axon via facilitated diffusion

  3. Na+ moves into the axon via facilitated diffusion

  4. Na+ moves out of the axon via facilitated diffusion
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

During depolarization, voltage-gated sodium channels open, allowing Na+ ions to rush into the axon down their concentration gradient via facilitated diffusion.

Multiple choice

An action potential consists of:

  1. Resting potential, depolarization and repolarization

  2. Depolarization and repolarization of the neuron

  3. Resting potential and depolarization

  4. Repolarization and resting potential
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An action potential is defined by the rapid change in membrane potential consisting of the depolarization phase (rising) and the repolarization phase (falling).

Multiple choice

The myelination of nerve fibres allows for:

  1. Saltatory conduction

  2. Continuous conduction

  3. Synaptic transmission

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

Myelin sheaths act as insulators that allow the action potential to jump between nodes of Ranvier, a process known as saltatory conduction.

Multiple choice

The function of neurons is to:

  1. Transmit chemical impulses

  2. Transmit electrical impulses

  3. Increase reaction time

  4. Decrease reaction time
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Neurons are specialized cells designed to transmit electrical impulses (action potentials) along their axons to communicate information.

Multiple choice

The sense of touch is caused by signals from _.

  1. nociceptors

  2. mechanoreceptors

  3. osmoreceptors

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

Mechanoreceptors are specialized sensory receptors that respond to mechanical pressure or distortion. Nociceptors detect pain, and photoreceptors detect light.