The rod receptor potential differs from other surface receptors in that it shows ______?: (A) Depolarization, (B) Decreased negativity, (C) Increased conductance of Sodium, (D) Hyperpolarization
Answer is D. The rod receptor potential differs from the outer surface receptors in that it shows Hyperpolarization. In most sensory receptors: Arrival of stimulus - Ion channels are opened up allowing current to flow - depolarisation of the receptor. In photoreceptors: When the light strikes the outer segment, a cascade of reactions are initiated, that close some of the Na+ channels in the outer segment and results in hyperpolarisation. Ref: Guyton and Hall 13th edition Pgno: 650-651