The body is organized on several different levels, from organ systems to cells. Groups of cells form tissues, and groups of tissues form organs. Organs then form organ systems. All parts of the body work together to maintain homeostasis, or keep internal conditions stable. Failure of homeostasis can be fatal.
Cell: Basic unit of structure and function.
Tissue: A cluster of cells with similar functions.
Organ: A group of tissues working together
Organ System: A group of organs working together.
Homeostasis: Process where the body tries to keep internal conditions stable.
Humans are organized at different levels in order of most general to most complex:
The cell is a basic unit of life, as it is the smallest unit capable of carrying out the functions of life.
Connected cells performing a similar function form a tissue.
Four basic types of tissues:
Organs are then made up of two or more types of tissues working together.
The organs can be organized into an overall organ system that performs a more complex job.