The visual system In the
visual system, sensory cells called
rod and
cone cells in the
retina convert the physical energy of
light signals into
electrical impulses that travel to the
brain. The light causes a conformational change in a protein called
rhodopsin.
The auditory system In the
auditory system, sound vibrations (mechanical energy) are transduced into electrical energy by hair cells in the inner ear. Sound vibrations from an object cause vibrations in air molecules, which in turn, vibrate the
ear drum. The movement of the eardrum causes the bones of the middle ear (the
ossicles) to vibrate. These vibrations then pass into the
cochlea, the organ of hearing. Within the cochlea, the hair cells on the sensory epithelium of the
organ of Corti bend and cause movement of the basilar membrane. The membrane undulates in different sized waves according to the frequency of the sound. Hair cells are then able to convert this movement (mechanical energy) into electrical signals (graded receptor potentials) which travel along auditory nerves to hearing centres in the brain.
The olfactory system In the
olfactory system, odorant molecules in the mucus bind to G-protein receptors on olfactory cells. The G-protein activates a downstream signalling cascade that causes increased level of cyclic-AMP (cAMP), which trigger neurotransmitter release.
The gustatory system In the
gustatory system, perception of five primary
taste qualities (sweet, salty, sour, bitter and umami [savoriness] ) depends on taste transduction pathways, through taste receptor cells, G proteins, ion channels, and effector enzymes.
The somatosensory system In the
somatosensory system the sensory transduction mainly involves the conversion of the mechanical signal such as pressure, skin compression, stretch, vibration to electro-ionic impulses through the process of
mechanotransduction. It also includes the sensory transduction related to
thermoception and
nociception. ==References==