Question 12: Distinguish between:
(a) afferent neurons and efferent neurons
(b) impulse conduction in a myelinated nerve fibre and unmyelinated nerve fibre
(c) aqueous humor and vitreous humor
(d) blind spot and yellow spot
(f) cranial nerves and spinal nerves.
Answer:
(a) Afferent neurons and efferent neurons
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Afferent neurons
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Efferent neurons
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Afferent neuron conducts nerve impulses toward the brain or the spinal cord.
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Efferent neuron conducts nerve impulses from the brain or spinal cord to the effector organs such as muscles or glands.
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(b) Impulse conduction in a myelinated nerve fibre and an unmyelinated nerve fibre
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Impulse conduction in a myelinated nerve fibre
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Impulse conduction in an unmyelinated nerve fibre
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1.
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In a myelinated nerve fibre, the action potential is conducted from one node to another.
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1.
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In an unmyelinated nerve fibre, the action potential is not conducted from node to node. It is carried along the whole length of the nerve fibre.
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2.
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The conduction of impulses is faster.
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2.
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The conduction of impulses is slower.
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(c) Aqueous humour and vitreous humour
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Aqueous humour
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Vitreous humour
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It is a thin, watery fluid present between the cornea and the lens.
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It is a transparent gel present between the lens and the retina.
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(d) Blind spot and yellow spot
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Blind spot
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Yellow spot
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1.
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Blind spot is a spot on the retina present at the point of origin of the optic nerve.
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1.
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Yellow spot is a small area on the retina present at the posterior pole of the eye, lateral to the blind spot.
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2.
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Photoreceptor cells are absent from this region.
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2.
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Only cones are present in this region.
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3.
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They are insensitive to light as both rods and cones are absent.
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3.
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They are sensitive to bright light as cones are present.
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(f) Cranial nerves and spinal nerves
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Cranial nerves
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Spinal nerves
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1.
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Cranial nerves arise from the brain.
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1.
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Spinal nerves arise from the spinal cord.
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2.
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There are 12 pairs of cranial nerves.
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2.
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There are 31 pairs of spinal nerves.
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Comments
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Accurate answer's from the exam point of view.
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