When Light of Suitable Wavelength Strikes a Photoreceptor, the Photopigment

question 103

Essay

When light of suitable wavelength strikes a photoreceptor, the photopigment (absorbs or reflects) the light, causing the photopigment to (dissociate or regenerate). This photopigment transformation acts through a second messenger system to cause Na⁺ channels in the outer segment to (open or close). Subsequently, the photoreceptor (depolarizes or hyperpolarizes), which results in a(n) (increase or decrease) in release of an (inhibitory or excitatory) transmitter from its synaptic terminal.

---

Definitions:

Myelin Sheath

Insulation around some nerve cell axons that allows nerve impulses to move more quickly through the axons.

Axons

Extended, thin extensions of neurons that convey electrical signals from the neuron's cell body outward.

Cerebral Cortex

The outer layer of neural tissue of the cerebrum of the brain, playing a key role in memory, attention, perception, cognition, awareness, thought, language, and consciousness.

Subarachnoid Space

The gap between the arachnoid membrane and the pia mater around the brain and spinal cord, filled with cerebrospinal fluid.