Five Senses

There are 5 senses which help us to understand different the world around us. They are smell, touch, sight and hearing. They help us in identifying different things, in finding food as well as they help keep us safe.

Sense of Sight or Vision

The eye is the organ which is responsible for vision. It consists of complex structure which consists of a lens which sends light to the retina, which covers two types of photoreceptor cells, which include the shape of cones and rods. The cone cells show sensitivity to light and color it is present on the part of the retina called the fovea, where the lens focuses light. The cells which are rod shaped have a high sensitivity to light and color. These rods present near fovea have responsibility for and night and peripheral vision. The eye is connected to the brain with the optic nerve. It is known as papilla due to its insensitivity to light. Scientific experiments reveal that the backside of the brain corresponds to the visual perception in the retina.

Brain is responsible for the combination of these images perceived by our eyes in a single three-dimensional image. Although the image on the retina is inverted by the action of the lens, brain correction and perceive objects in their original position. Experiments with goggles that invert images through prisms have shown that individuals face confusion initially, but eventually perceive the images properly.

Vision is most important of all the senses but over exposure to the sun and below than normal nutrition level can lead to age-related macular degeneration (ARMD) as well as cataracts. ARMD can be defined as loss of clear vision and can lead to visual impairment. (Greenough, Black & Wallace, pp. 539-559)

Figure 1

Sense of Hearing or Hearing

The ear is the organ which is responsible for hearing. It is the outer ear protruding from the cup-shaped head to direct the sound towards the eardrum. The vibrations are transmitted to the internal ear through several small bones located which are called the hammer, anvil and stirrup. The cochlea or inner ear is a spiral-shaped chamber whose interior is covered with fibbers that react to transfer all impulses to vibrations the brain through auditory nerve. Then brain sends signals from ears in order to determine the distance and direction of sounds.

The vestibular system in the inner ear has three semicircular canals that are responsible for balancing as well as spatial orientation. It also consists of cavities which consist of a viscous liquid (endolymph) and minute particles (statoliths) which consist mainly of calcium carbonate. The movement of on the inner ear cells which sends signals to the brain that is interpreted as acceleration and motion.

Hearing is most likely to be lost with age. One in the three people belonging to the age group 65 and older, while 50% of those age 85 and older suffer from hearing loss from mild to severe. Optimal use of Vitamin D and calcium show a reduction in the symptoms of hearing ...