How does one maintain balance in a weightless environment?
In order to understand how our bodies maintain balance in a weightless environment, it is essential to discuss first how we maintain balance here on Earth. The ability to sense motion and position can be attributed to the vestibular organs, or the vestibular apparatus collectively, located in each inner ear. Three membranous semicircular canals and two large sacs, the utricle and saccule, make up the vestibular apparatus, and they all share a common sensor – the hair cell. Inside a widened area of each canal called the ampulla resides fluid and hair receptor cells, which are surrounded by a fragile membrane called the cupula. With each movement, no matter how slight, the ampulla pushes the cupula, which in turn nudges against sensory hairs. The movement of sensory hairs stimulates the hair cells, and consequently sends sensory impulses down the vestibular nerve to the brain. Each canal is located in one of three planes of space, thus acquiring a sense of all possible head movement comb
