Chapter 18: Neural Control and Coordination Assertion-Reason Questions | biology Class 11 CBSE

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 1

Logic Check

Assertion (A): The neural system provides an organised network of point-to-point connections for quick coordination. Reason (R): The endocrine system provides chemical integration through hormones, which is a slower process.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 2

Logic Check

Assertion (A): Neurons are described as excitable cells. Reason (R): The membranes of neurons are maintained in a polarised state due to a differential concentration gradient of ions across the membrane.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 3

Logic Check

Assertion (A): The outer surface of the resting axonal membrane is negatively charged. Reason (R): The sodium-potassium pump transports 3 Na+ outward and 2 K+ into the cell, making the outer surface positively charged.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 4

Logic Check

Assertion (A): Myelinated nerve fibres are found in spinal and cranial nerves. Reason (R): The myelin sheath is formed by Schwann cells that wrap around the axon.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 5

Logic Check

Assertion (A): Impulse transmission across an electrical synapse is faster than across a chemical synapse. Reason (R): At electrical synapses, the membranes of pre- and post-synaptic neurons are in very close proximity, allowing electrical current to flow directly without neurotransmitter involvement.

Reasoning Options

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Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 6

Logic Check

Assertion (A): Nissl's granules are found in both the cell body and the axon of a neuron. Reason (R): Dendrites also contain Nissl's granules and carry impulses towards the cell body.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 7

Logic Check

Assertion (A): The cerebral cortex is called grey matter. Reason (R): Neuron cell bodies are concentrated in the cerebral cortex, giving it a greyish appearance.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 8

Logic Check

Assertion (A): The corpus callosum connects the left and right cerebral hemispheres. Reason (R): The corpus callosum is a tract of nerve fibres that enables communication between the two hemispheres.

Reasoning Options

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Assertion-Reason

Easy difficulty • Check the statement and reason

Easy

Question 9

Logic Check

Assertion (A): The cerebellum has a very convoluted surface. Reason (R): The convoluted surface of the cerebellum provides additional space for many more neurons, increasing its functional capacity.

Reasoning Options

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Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 10

Logic Check

Assertion (A): The axoplasm inside the resting axon has a high concentration of Na+ ions. Reason (R): The resting axonal membrane is comparatively more permeable to K+ and nearly impermeable to Na+.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 11

Logic Check

Assertion (A): Unipolar neurons are found usually in the embryonic stage. Reason (R): Unipolar neurons have a cell body with only one axon and no dendrites.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 12

Logic Check

Assertion (A): The hypothalamus is involved in the regulation of sexual behaviour and emotional reactions. Reason (R): The hypothalamus, along with the limbic system, controls sexual behaviour, emotional reactions such as excitement, pleasure, rage, and fear, and motivation.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 13

Logic Check

Assertion (A): The medulla oblongata is the part of the forebrain that controls respiration and cardiovascular reflexes. Reason (R): The medulla oblongata is part of the hindbrain and contains vital reflex centres that control respiration, cardiovascular reflexes, and gastric secretions.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 14

Logic Check

Assertion (A): The somatic neural system relays impulses from the CNS to skeletal muscles. Reason (R): Skeletal muscles are under voluntary control and require conscious neural input from the CNS via the somatic neural system.

Reasoning Options

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Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 15

Logic Check

Assertion (A): After depolarisation, K+ ions diffuse inward to restore the resting potential. Reason (R): The resting potential is restored when K+ diffuses outside the membrane, re-establishing the positive charge on the outer surface.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 16

Logic Check

Assertion (A): The thalamus is described as the major coordinating centre for sensory and motor signalling. Reason (R): The cerebrum wraps around the thalamus, and the hypothalamus lies at the base of the thalamus.

Reasoning Options

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Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 17

Logic Check

Assertion (A): Electrical synapses are the most common type of synapse in the human neural system. Reason (R): Electrical synapses allow faster transmission compared to chemical synapses because current flows directly between neurons.

Reasoning Options

ByteNotes

Assertion-Reason

Hard difficulty • Check the statement and reason

Hard

Question 18

Logic Check

Assertion (A): The action potential generated at site A propagates to site B along the axon. Reason (R): Current flows on the inner surface from site A to site B and on the outer surface from site B to site A, reversing polarity at B and generating an action potential there.

Reasoning Options

ByteNotes

Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 19

Logic Check

Assertion (A): Bipolar neurons are found in the cerebral cortex. Reason (R): Bipolar neurons have one axon and one dendrite and are found in the retina of the eye.

Reasoning Options

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Assertion-Reason

Medium difficulty • Check the statement and reason

Medium

Question 20

Logic Check

Assertion (A): The new potential generated in the post-synaptic neuron after neurotransmitter binding can be either excitatory or inhibitory. Reason (R): The neurotransmitters bind to specific receptors on the post-synaptic membrane, opening ion channels that generate a new potential whose nature depends on the ions that enter.

Reasoning Options

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Chapter sections

Chapter 18: Neural Control and Coordination | Assertion-Reason

Assertion (A): The neural system provides an organised network of point-to-point connections for quick coordination. Reason (R): The endocrine system provides chemical integration through hormones, which is a slower process.

Assertion (A): Neurons are described as excitable cells. Reason (R): The membranes of neurons are maintained in a polarised state due to a differential concentration gradient of ions across the membrane.

Assertion (A): The outer surface of the resting axonal membrane is negatively charged. Reason (R): The sodium-potassium pump transports 3 Na+ outward and 2 K+ into the cell, making the outer surface positively charged.

Assertion (A): Myelinated nerve fibres are found in spinal and cranial nerves. Reason (R): The myelin sheath is formed by Schwann cells that wrap around the axon.

Assertion (A): Nissl's granules are found in both the cell body and the axon of a neuron. Reason (R): Dendrites also contain Nissl's granules and carry impulses towards the cell body.

Assertion (A): The cerebral cortex is called grey matter. Reason (R): Neuron cell bodies are concentrated in the cerebral cortex, giving it a greyish appearance.

Assertion (A): The corpus callosum connects the left and right cerebral hemispheres. Reason (R): The corpus callosum is a tract of nerve fibres that enables communication between the two hemispheres.

Assertion (A): The cerebellum has a very convoluted surface. Reason (R): The convoluted surface of the cerebellum provides additional space for many more neurons, increasing its functional capacity.

Assertion (A): The axoplasm inside the resting axon has a high concentration of Na+ ions. Reason (R): The resting axonal membrane is comparatively more permeable to K+ and nearly impermeable to Na+.

Assertion (A): Unipolar neurons are found usually in the embryonic stage. Reason (R): Unipolar neurons have a cell body with only one axon and no dendrites.

Assertion (A): The hypothalamus is involved in the regulation of sexual behaviour and emotional reactions. Reason (R): The hypothalamus, along with the limbic system, controls sexual behaviour, emotional reactions such as excitement, pleasure, rage, and fear, and motivation.

Assertion (A): The medulla oblongata is the part of the forebrain that controls respiration and cardiovascular reflexes. Reason (R): The medulla oblongata is part of the hindbrain and contains vital reflex centres that control respiration, cardiovascular reflexes, and gastric secretions.

Assertion (A): The somatic neural system relays impulses from the CNS to skeletal muscles. Reason (R): Skeletal muscles are under voluntary control and require conscious neural input from the CNS via the somatic neural system.

Assertion (A): After depolarisation, K+ ions diffuse inward to restore the resting potential. Reason (R): The resting potential is restored when K+ diffuses outside the membrane, re-establishing the positive charge on the outer surface.

Assertion (A): The thalamus is described as the major coordinating centre for sensory and motor signalling. Reason (R): The cerebrum wraps around the thalamus, and the hypothalamus lies at the base of the thalamus.

Assertion (A): Electrical synapses are the most common type of synapse in the human neural system. Reason (R): Electrical synapses allow faster transmission compared to chemical synapses because current flows directly between neurons.

Assertion (A): The action potential generated at site A propagates to site B along the axon. Reason (R): Current flows on the inner surface from site A to site B and on the outer surface from site B to site A, reversing polarity at B and generating an action potential there.

Assertion (A): Bipolar neurons are found in the cerebral cortex. Reason (R): Bipolar neurons have one axon and one dendrite and are found in the retina of the eye.

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