Understanding Vision Physiology Mechanism in 60 Seconds #medicalstudent #vision #physiology

What hidden symphony unfolds in the eye when light dances upon the retina, sparking the marvel of vision? At the heart of this magic are photoreceptors—delicate rods and cones—poised like sentinels to intercept light. Each photon triggers a quantum stir, altering the shape of rhodopsin in rods or photopsins in cones, akin to the twist of a key unlocking a door. This subtle shift activates the G-protein transducin, prompting it to exchange GDP for GTP. The GTP-bound transducin stimulates phosphodiesterase (PDE), which swiftly reduces cyclic GMP (cGMP) levels. As cGMP diminishes, cGMP-gated sodium channels close, halting the sodium influx and leading to the hyperpolarisation of the photoreceptor membrane.
This hyperpolarisation orchestrates a decrease in the release of the neurotransmitter glutamate at the synaptic terminal, a critical moment that alters communication with downstream bipolar and horizontal cells. In this elegant cascade, light transforms from ephemeral photons into electrical impulses and neurotransmitter signals, delivering the very essence of vision to the brain—a journey where the ordinary becomes extraordinary.

Видео Understanding Vision Physiology Mechanism in 60 Seconds #medicalstudent #vision #physiology канала Medical Physiology: Prof. John 8-12