Tag: coordination

Questions Related to coordination

Primary function of myelin sheath around vertebrate axon is to

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

  1. Regulate Na-K pump

  2. Increase in size of action potential

  3. Increase in speed of conduction by preventing leakage of nerve impulse

  4. Deactivate the release of neurotransmitter

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Correct Option: C

Characteristics of graded potential is

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

  1. Always followed by a refractory period

  2. Amplitude is always the same

  3. Duration and strength varies

  4. All or none response

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Correct Option: C

Choose the correct statements

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

  1. Nonmyelinated nerve fibres are found in spinal and cranial nerves

  2. Retina has multipolar neurons

  3. Electrical synapses are commonly present in humans

  4. Impulse transmission across an electrical synapse is faster than across a chemical synapse

  5. In resting neuron, axoplasm inside the axon contains high concentration of sodium ion

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Correct Option: D

Which of the following statements are correct regarding Na+ - K+ pump?


(i) Needs energy (ATP) to work.
(ii) Expels 3 Na+ for every 2K+ ions imported
(iii) Works against a concentration gradient
(iv) Maintains resting potential

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

  1. (i) and (iv)

  2. (ii) and (iii)

  3. (i) and (iii)

  4. All of these

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Correct Option: D

Which is wrong regarding conduction of nerve impulse

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

  1. In a resting neuron, the axonal membrane is more permeable to $K^+$ ions and nearly impermeable to N$a^+$ ions

  2. Fluid outside the axon has a high concentration of N$a^+$ and low concentration of $K^+$, in a resting neuron

  3. Resting potential is the electrical potential difference across the resting membrane

  4. A neuron is polarised only when the outer surface of axonal membrane possesses a negative charge and inner surface is positively charged

  5. Ionic gradients are maintained by Na-K pumps across the resting membrane which transports 3 N$a^+$ ions outwards for 2$K^+$ ions into the cell

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Correct Option: D

Nerve impluse transmission at neuromuscular junction requires

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

  1. Ca

  2. Fe

  3. Cl

  4. Mg

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Correct Option: A

Depolarisation of nerve membrane takes place through influx of .. ions

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

  1. Calcium

  2. Potassium

  3. Sodium

  4. Magnesium

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Correct Option: C


In the resting state, the axonal membrane is (i)_ with more (ii) charged ions outside than inside. This unequal distribution of ions is due to (1) the selective permeability of the membrane, which forms an almost impenetrable barrier to (iii) and (2) the action of the _(iv), which pumps (v) Na$^+$ out of the neuron for every _(vi) K$^+$ brought in.
Select the option that correctly fills the blanks in the paragraph.

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

  1. (i) - depolarised, (ii) - positively, (iii) - Na$^+$, (iv) - sodium - potassium pump, (v) - three, (vi) - two

  2. (i) - depolarised, (ii) - negatively, (iii) - Na$^+$, (iv) - sodium - potassium pump, (v) - three, (vi) - two

  3. (i) - polarised, (ii) - negatively, (iii) - Na$^+$, (iv) - sodium - potassium pump, (v) - three, (vi) - two

  4. (i) - polarised, (ii) - positively, (iii) - Na$^+$, (iv) - sodium - potassium pump, (v) - three, (vi) - two

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Correct Option: D
Explanation:

In the resting state, the axonal membrane is polarised with more positively charged ions outside than inside, unequal distribution of ions is due to the selective permeability of the membrane, which forms impermeable barrier to sodium ion and the action of the sodium which pumps three sodium ions out of the neuron for every two potassium ions brought in.

Thus, the correct option is '(i) - polarised, (ii) - positively, (iii) - Na$^+$, (iv) - sodium - potassium pump, (v) - three, (vi) - two.'

Sodium potassium pump transports

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

  1. Na+ and K+ out of the neuron

  2. Na+ and K+ into the neuron

  3. Na+ into the neuron and K+ out of the neuron

  4. K+ into the neuron and Na+ out of the neuron

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Correct Option: D

Diencephalon is the centre for the following except

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

  1. Sweating

  2. Sneezing

  3. Thirst

  4. Hunger

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Correct Option: B