Senses are transducers from the physical world to the realm of the mind
The sensory organs detect all types of changes in the environment and send appropriate signals to the central nervous system, where all the inputs are processed and analyzed.
A sensory system is a considered as a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory receptors to recognize the stimuli, neural pathways to carry that stimuli, and parts of the brain involved in sensory perception. Most commonly known sensory systems are those for vision, auditory (hearing), somatic (touch), gustatory (taste), olfaction (smell) and vestibular (balance/movement). Sensory reception occurs through a process known as signal transduction, in which stimuli are converted into nerve impulses and relayed to the brain. Putting simply, senses are transducers from the physical world to the realm of the mind where we interpret the information, creating our perception of the world around us.
The somatic cells present in the body respond to both external and internal stimuli. Due to these stimuli, we feel the climatic changes in the environment, we see an object and its color, and we hear a sound. Although most of the somatic receptors are located in the skin (conveying the external sensations of touch, heat, cold, pressure, and pain), others are located in internal organs (e.g.; the heart and the stomach). Somatic sensations such as hunger, thirst, and fatigue are thought to originate in specific areas of the nervous system. The sense of balance, or equilibrium, is related to the flow of endolymph, a fluid found in the inner ear.
Thus, the sensory organs detect all types of changes in the environment and send appropriate signals to the central nervous system, where all the inputs are processed and analyzed. Signals are then sent to different parts or centers of the brain. This is how we can sense changes in the environment.