Question

describe the structures responsible for the special senses of taste smell hearing balance and vision

Answer 1

General senses present in the human body are taste, smell, hearing and vision. There are certain structures associated which are responsible for these senses.

Taste: gustation or the taste is the sense that associated with the structure called tongue. Tongue has papilla that contain taste buds which has specialized gustatory receptor cells. These help in the transduction of taste stimuli like sweet, bitter etc.

Smell: the olfaction or smell is the sense associated with the structure called nose. The olfactory receptors are responsible for smell which are present in the superior nasal cavity. This region is called as olfactory epithelium which contain bipolar sensory neurons. These sensory neurons contain dendrites which are leading to mucus lining of the cavity. Whenever we inhale the smell lead to the epithelial region and dissolve into the mucus and than through the neurons give signal to the brain.

Hearing: audition or hearing is the sense associated with the structure called ear. The sound travel from external ear through C shaped pinnae and than move to middle ear with the help of osicle bones. these bones help in travelling the sound to inner ear where sound wave transduced into the neural signal. The inner ear has two regions vestibule and cochlea which are responsible for hearing and balancing respectively.

Touch: somatosensation is the sense associated with the structure called skin as their major receptors are present on the skin. somatosensory signals are passed through neutrons with the with the help of free nerve ending. The signal passed are pain and temperature. Thermoreceptors helps in transducing temperature stimuli and nocieceptor help in transduction of pain stimuli.

vision: this sense is associated with the structure celled eye. This is based on the light received through the eyes. The retina is composed of several layers and contains specialized cells for the initial processing of visual stimuli. Light falling on the retina causes chemical changes to pigment molecules in the photoreceptors, ultimately leading to a change in the activity of the RGCs. Photoreceptor cells have two parts, the inner segment and the outer segment. The inner segment contains the nucleus and other common organelles of a cell, whereas the outer segment is a specialized region in which photoreception takes place. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer segment. The rod-shaped outer segments of the rod photoreceptor contain a stack of membrane-bound discs that contain the photosensitive pigment rhodopsin. The cone-shaped outer segments of the cone photoreceptor contain their photosensitive pigments in infoldings of the cell membrane. There are three cone photopigments, called opsins, which are each sensitive to a particular wavelength of light. The wavelength of visible light determines its color. The pigments in human eyes are specialized in perceiving three different primary colors: red, green, and blue.