Human Body Systems

homeostasis

process by which organisms maintain a relatively stable internal environment

organ systems

There are eleven organ systems in the human body. An organ system is a group of organs that perform closely related functions.

nervous tissue

Transmits nerve impulses throughout the body

connective tissue

Connective tissue provides support for the body and connects its parts.

epithelial tissue

Epithelial tissue includes glands and tissues that cover interior and exterior body surfaces.

organs

In an organ, distinct tissue types work together to perform a single function. For example in the eye, epithelial tissue, nervous tissue, muscle tissue, and connective tissue work together to sense light and color.

maintaining a stable body temperature

Nerve cells sense temperatures on the surface of the body at the skin and organs of the body in the core. Chemical signals from the brain increase cellular activities to warm the body or decrease cellular activity to lower the production of heat, initiating a complex set of responses in either instance.

Cells, tissues, organs, and organ systems

Tissues are groups of similar cells that perform a single function, like muscle tissue. An organ is a group of tissues that work together to form a complex function, such as sight. An organ system is a group of organs that perform closely related functions.