Human body from organs to the cells of which they are composed. The human body consists of many interacting systems of organs. These interact to maintain homeostasis, keeping the body in a stable state with safe levels of substances such as sugar and oxygen in the blood. Each system contributes to homeostasis, of itself, other systems, and the entire body. Some combined systems are referred to by joint names. For example, the nervous system and the endocrine system operate together as the neuroendocrine system. The nervous system receives information from the body, and transmits this to the brain via nerve impulses and
Human microbiota Recently, the more appropriate term "microbiota" is applied, though its use has not eclipsed the entrenched use and recognition of "flora" with regard to bacteria and other microorganisms. Both terms are being used in different literature. As of 2014, it was often reported in popular media and in the scientific literature that there are about 10 times as many microbial cells in the human body as there are human cells; this figure was based on estimates that the human microbiome includes around 100 trillion bacterial cells and that an adult human typically has around 10 trillion human cells. In 2014,