Question

Describe the process involved in human sensory transduction (the transformation of physical signals, i.e., light and sound) into neural messages for sight, hearing, somato-sensation, olfaction, and gestation.

Answer 1

Transduction basically is defined as the process of transformation of physical energy into electrical voltage or potential and this potential is called Receptor Potential.

In some Senses, Receptor potential directly triggers Nerve impulses that travel to central nervous system.

In other Senses, Receptor potential first leads to some electrical events which then trigger nerve impulses. Then, these impulses travel to Central nervous System.

Transduction in Vision:

As we know, there are photoreceptor cells presents in retina i.e. rods and cones, transduction occurs at these receptors. Rods and Cones contain photosensitive pigments. When electromagnetic waves in the form of light strikes on these cells after reaching to retina, some of the light energy is absorbed by these receptors which changes the configuration of the photosensitive pigments present in these cells, and this process creates electrical energy.

For ex.- Rhodopsin( pigment in rods) which exists in cis-rhodopsin configuration when not excited, changes into trans-rhodopsin configuration after absorbing the light.

These changes generates potential, through further electrical steps involving horizontal cells, bipolar cells, amacrine cells, further reaches to ganglion cells of the retina. These Ganglion cells make the optic nerve of the eye. Through optic nerve, this energy reaches to optic chiasm and to further brain areas.

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