This means that the bones sense the reduced load placed on them and they respond by losing calcium. The increased calcium in the urine can lead to kidney stones, and a continuous loss of calcium weakens bone. NASA-supported research is looking at the basic ways that cells can sense the effects of gravity. A better understanding of this process may lead to ways to prevent both kidney stones and the bone loss of osteoporosis. Muscles and bones are part of the structure of the human body, and we need this structure to work against gravity.
Plants have a structure as well, and it's also affected by gravity.
For example, a tree's wood allows it to stand up against the forces of gravity, and wood production is sensitive to gravity. This is true of all the major trees, like Douglas fir, that are used extensively for construction. Plants that are blown over by wind or rain can right themselves, again demonstrating the ability of plants to sense and work against gravity. This ability is important for harvesting the plant. Plants that can quickly right themselves produce higher yields.