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.
Answers
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Answer:
(a) Afferent neurons are sensory neurons that carry nerve impulses from sensory stimuli towards the central nervous system and brain, while efferent neurons are motor neurons that carry neural impulses away from the central nervous system and towards muscles to cause movement.
(b) The myelinated nerve fibers have nodes of Ranvier while unmyelinated nerve fibers do not have nodes of Ranvier. ... Due to presence of myelin sheath, myelinated nerves do not lose the impulse during conduction whereas unmyelinated nerve fibers can lose the nerve impulse during conduction.
(c) Aqueous humor is a clear liquid found between the cornea and the lens of eye, whereas vitreous humor is a clear gelatinous mass found in the rear part of the eyeball between the lens and retina. ... Vitreous humor does not replenish while aqueous humor does.
(d) Blind spot is a spot on the retina present at the point of origin of the optic nerve. Yellow spot is a small area on the retina present at the posterior pole of the eye, lateral to the blind spot. Photoreceptor cells are absent from this region.
(f) Cranial nerves are mixed nerves, where they carry both sensory and motor fibers whereas spinal nerves are mixed nerves. Cranial nerves are involved in vision, sense of the smell, hearing, sense of taste and eye movements
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