(a) Role of Na+ in the generation of action potential.

(b) Mechanism of generation of light-induced impulse in the retina.

(c) Mechanism through which a sound produces a nerve impulse in the inner ear.

Answers:

(a) When nerve fiber is stimulated, the sodium channels of the neurilemma are open and active. From the outside, sodium ions disperse the intracellular fluid due to the established electrochemical gradient. The membrane is negatively charged externally as potassium ions are released and are properly charged internally. Rapid changes in the membrane are known to act as potentially weakening of the membrane.

(b) The human eye contains a number of visual cues known as retinal and opsin. This separation is when light causes a change in the structure of the opsin, triggering a potentially potent action on bipolar neurons. These powerful actions or desires are transmitted to the cerebral cortex by the optic nerve where these desires are studied for analysis, to see a well-formed image.

(c) The vibration is detected by a membrane that encloses the ovalis of the fenestra by the perilymph of the inner ear. From here (perilymph), vibration is transmitted to the scala vestibule of the cochlea and in addition to the scala media by the Reissner membrane, which creates the corneal hair follicles, which is the sensory organ. These hair cells receive pressure to take to the brain through the ear canal, where the sense of hearing is affected.