Podcast
Questions and Answers
What is the primary mechanism by which photoreceptors become hyperpolarized in the dark?
What is the primary mechanism by which photoreceptors become hyperpolarized in the dark?
- The activation of a sodium-potassium pump, expelling Na+ ions
- The closure of Na+ and Ca2+ channels, allowing K+ to flow out
- The presence of cGMP, which keeps ion channels open for Na+ and Ca2+ influx (correct)
- The opening of Cl- channels, allowing negative ions to enter
What initiates the process of photoreceptor hyperpolarization when light hits the retina?
What initiates the process of photoreceptor hyperpolarization when light hits the retina?
- The depolarization of neighboring bipolar cells, which inhibits the photoreceptors
- The activation of rhodopsin, which triggers cGMP to leave the ion channel gate (correct)
- The direct closure of Na+ and Ca2+ channels by the incoming photons
- The release of a neurotransmitter that binds to and closes ion channels
What is the primary consequence of ion channel closure in photoreceptors during light exposure?
What is the primary consequence of ion channel closure in photoreceptors during light exposure?
- Na+ and Ca2+ can no longer flow in, but K+ can flow out, causing hyperpolarization (correct)
- The photoreceptor becomes completely impermeable to all ions, resulting in no change in membrane potential
- Cl- ions begin to flow out, causing depolarization of the photoreceptor
- The sodium-potassium pump is activated, expelling Na+ and allowing K+ influx
What is the function of the optic nerve in visual processing?
What is the function of the optic nerve in visual processing?
What is the primary role of the lateral geniculate nucleus (LGN) in visual processing?
What is the primary role of the lateral geniculate nucleus (LGN) in visual processing?
What is the primary function of the primary visual cortex (V1/Brodmann's area 17)?
What is the primary function of the primary visual cortex (V1/Brodmann's area 17)?
Which of the following is NOT a correct step in the visual processing pathway?
Which of the following is NOT a correct step in the visual processing pathway?
Which of the following statements about the optic chiasm is INCORRECT?
Which of the following statements about the optic chiasm is INCORRECT?
Which of the following statements about photoreceptor hyperpolarization is CORRECT?
Which of the following statements about photoreceptor hyperpolarization is CORRECT?
What is the primary function of the retina in visual processing?
What is the primary function of the retina in visual processing?