Eye – sight
The only vision organ in our body is eye. The eye is connected to the brain through the optic nerve and the point of this connection is called the "blind spot" because it is highly sensitive to light. Furthermore experiments have shown that the back of the brain maps the visual input from the eyes. An eye has a dynamic structure consisting of a transparent lens that focuses light on the retina. The retina is covered with two basic types of light-sensitive cells-rods and cones. The light is focused by the cone cells which are sensitive to color and they are located in the part of the retina. The rod cells are not sensitive to color, but it have got a greater sensitivity to light than the cone cells.

The brain combines the input of our two eyes into a single three-dimensional image. Additionally even though the image on the retina is upside-down because of the focusing action of the lens, the brain converts and provides the right-side-up perception.
The iris actually is a pigmented muscle that controls the size of the pupil, which dilates to allow more light into the eye or contracts to allow less light into the eye. The iris and pupil are covered by the cornea.
The range of perception of the eye is phenomenal. In the dark, the eye perception would be a substance produced by the rod cells which increases the sensitivity of the eye so that it is possible to detect very dim light.
Strong light, the iris contracts reducing the size of the lens that admits light into the eye and a protective obscure substance reduces the exposure of the light-sensitive cells. Ears - Hearing
The organ for hearing in our body is the ears. The outer ear which appears away from the head and is shaped to direct sounds toward the tympanic membrane, which he organ that transmits vibrations to the inner ear through a series of small bones in the middle ear called the malleus, incus and stapes.
The inside ear is a spiral-shaped chamber which is covered internally by nerve fibers that react to the vibrations and transmit sounds to the brain via the auditory nerve. The brain combines the input of our two ears to determine the direction as well as to identify the distance of sounds.
The human ear can perceive frequencies from 16 cycles per second, which is a very deep bass, to 28,000 cycles per second, which is a very high pitch.
The human ear can detect pitch changes from three percent of the original frequency in some frequency ranges.
To hear, the ear must respond to mechanical stimulation by sound waves. Ear is not only for hearing but it helps us to balance the sounds.

Tounge -Taste

The indicators for taste is called as taste buds which are situated chiefly in the tongue, but they are also located in the roof of the mouth too. The little bumps on our tongue are the taste buds.
They are able to identify four basic tastes: salty, sweet, bitter, and sour.
When we put something into our mouth, the taste buds in our tongue can identify what chemicals we are ingesting.
Generally, the taste buds close to the tip of the tongue are very sensitive to identify sweet tastes, whereas the taste buds in the back of the tongue are sensitive to identify bitter tastes.
The taste buds on top and on the side of the tongue are sensitive to salty and sour tastes.
At the middle of each taste bud there is a nerve that sends the sensations to the brain.
The sense of taste is mainly combined with the sense of smell.
The number of taste buds varies substantially from one individual to another individual, but greater numbers increase sensitivity. Experiments shows that Women, in general, have a greater number of taste buds than men. As in the case of color blindness, some people have lost the insensitive to some taste

Nose - Smell

The nose is the organ which is responsible for the sense of smell and the main organ which identifies the smell.
The cavity of the nose is built with muscles that have smell identifiers connected to the brain nerve.
The smells themselves consist of various substances.
The smell identifiers are sensitive to seven types of sensations which are camphor, musk, flower, mint, ether, acrid, or putrid.
The sense of smell is sometimes temporarily lost when a person has got a cold beacause it will lose some smell identifiers. Dogs have a sense of smell that is many times more sensitive than man's.

Touch

The sense of touch is distributed throughout the body and it can be felt with any part of the body. Nerve endings in the skin and other parts of the body transmit sensations to the brain. Some parts of the body have a larger number of nerve endings and, therefore they are more sensitive.
Four kinds of touch sensations that can be identified are cold, heat, contact, and pain.
Hairs which are in the skin as protectors magnify the sensitivity and act as an early warning system for the body.
The fingertips and the sexual organs have the greatest concentration of nerve endings.
The skin identifiers can detect touch, pain, pressure, and temperature. Throughout the skin, we have all four of these interconnected.
Skin receptors generate a notice to the brain when activated, which is carried to the spinal cord and then to the brain.
The skin is not the tissue in the body to have identifiers but it acts as a protector to the body.