Post 496 by Gautam Shah
In buildings and landscapes we move around with natural care. The care includes maintaining balance, controlling the speed of movement, knowing which of the body limbs are where, the direction of movement, orientation of the body and postural position. We sense our own body movement and external forces that quicken or slow it down, without using other sensual faculties. We sense the position of our body and the direction of movement. We also perceive the spatial position and orientation with three-dimensional references. And yet within that we attain and maintain the postural equilibrium.
Balance and movement are two interconnected experiences. Balance, equilibrioception, or vestibular sense is the sense that allows an organism to sense body Movement, Direction, and Acceleration. The organ of equilibrioception is the vestibular labyrinthine system found in both of the inner ears. In technical terms, this organ is responsible for two senses of angular momentum acceleration and linear acceleration (which also senses gravity), but they are known together as equilibrioception.
The vestibular system, in most mammals, is the sensory system which is the main contributor for the sense of balance and spatial orientation. This serves the purpose of coordinating movement with balance. The vestibular system contains three semicircular canals in each labyrinth, generating three-dimensional sense. Perceptions through the vestibular system are very fast and can generate responses to maintain perceptual and postural stability. But yet compared to sensual perceptions like vision, touch and audition, the responses are little delayed.
Kinesthesis is the sense of the position and movement of body parts. Through Kinesthesis, people know where all the parts of their bodies are, how and which-way (direction) they are moving. Kinesthetic sense, provides the parietal cortex of the brain with information on the relative positions of the parts of the body. Receptors for Kinesthesis are located in the muscles, joints, and tendons.
The sense of balance or equilibrium provides information about where the body exists in space. When the vestibular system gets stimulated, in absence of any other perceptions (like seeing, hearing or touching) we still experience the body movement. In space craft, engineers are checked for their sense of perceptivity of balance and equilibrium in darkness and near zero sound environments. We control speed of movement while going down a hill. The sense of going up or down on a clockwise or anti-clock-wise spiral stair is predictable, because we relate to all those experiences in some other references. ‘A person in complete darkness and sitting in a chair will feel that he or she has turned to the left if the chair is turned to the left’. Similarly, the sense of balance tells people ‘whether they are standing up, falling in an elevator, or riding a roller coaster’.