Light activates the photopigment, reducing cGMP, closing Na+ channels, hyperpolarizing the photoreceptor, releasing bipolar cells from inhibition, and allowing signal transmission to the ganglion.
La lumière active le photopigment, réduisant le cGMP, fermant les canaux Na+, hyperpolarisant le photorécepteur, libérant les cellules bipolaires de l'inhibition et permettant la transmission du signal au ganglion.
| Front | Explain physiology of photoreceptors in the light |
|---|---|
| Back | 1. Light is absorbed by the photopigment 2. Cis retinal changes to trans-rettinal and activates opsin 3. Activated opsin triggers a cascade of events that reduces levels of cGMP 4. Less cGMP, Na+ channels close (dark current ceases), which hyperpolarizes the photoreceptor 5. Hyperpolarized photoreceptor can no longer inhibit the bipolar cells 6. Bipolar cells are now free to release excitatory NT to stimulate ganglion cells which relay nerve impulses to the brain through the optic nerve |
Learn with these flashcards. Click next, previous, or up to navigate to more flashcards for this subject.
Next card: Draw physiology photoreceptors light the
Previous card: Draw photoreceptor dark a in
Up to card list: Anki Anatomy, physiology, microbiology