Sensation is the activation of the sense organs by any source of physical energy. Stimulus is the energy that produces a response in a sense organ. Stimuli vary in both type and intensity. Different types of stimuli activate different sense organ.

Sensation is a process which information from the outside world enters in to the brain. It is the subjective experiences of a physical stimulus. Human life would be very different without our ability to sense and perceive. We can see, hear, feel, taste, smell or sense because of our sense organs and nervous.

Sensation beings with stimulation of each of these receptions. The receptors encode messages for the brain. Sensation is defined as just awareness us stimulate. It is the stimulation of sensory receptor and the bans occurs when special receptor in the sense organ, the eyes, ear, nose, tongue and skin are activated allowing various forms of outside stimuli to become neutral signal in the brain. Sensation refers to the activation of the receptors. Receptors are the basic structure of sensation.

Sensation: (Sense Organ)

a) The visual sense:

Shedding light on the eye. (Eye: Vision is the most important of all the senses. In order to understand visual sensation, it is necessary to have knowledge of light energy. Sending the message from the eye to the brain).

(Light, a candle flame seen 30 miles on a dark night)

b) The auditory sense

(ear: hearing, Audition is the second important senses after vision. The link between how we hear and what we hear is possible through sound waves. Sound is the movement of air molecules brought about by a source of vibration).

(The tick of a watch under quite condition at 20 ft.)                                   

c) The chemical sense

(nose: smell and tongue: taste, the senses of smell (olfaction) and the senses of taste (gestation) both respond to substances in solution in the form of gas or fluid that is the reason smell and taste are referred to as the chemical senses. Smell may also act as a hidden means of communication for humans. The sense of taste involves receptor cells that respond to four basic stimulus qualities: sweet, sour, salty, and better).

(One tea spoons of sugar in a cup of tea and one drop of perfume diffuse into the entire volume of a room.)

d) The skin sense

(temperature, pain, pressure etc. As the chemical sense include taste and smell so as the body sense includes: Vestibular sense: the sense of balance, kinaesthetic sense: the sensation of body movement and position and coetaneous sense: Touch, pressure, temperature and pain. Skin sensitivity in various area of the body).(Touch, the wing of a bee following on your check from a height of 1 cm.)

Structure and Functions of Visual and Auditory Sensation

Structure of the eye: Eye is the window to the soul and the world. It involves different chain of actions to make us see the world.

The auditory system: Ear is composed of three components. The outer ear, middle ear, and the inner ear.