Each structure in the body carries out functions necessary for life.
These functions can be grouped into 6 categories:
For the body to function effectively there must be organization and separation.
For example, blood will only flow if it is kept inside your circulatory system.
The integumentary system, which includes the skin, hair, nails and exocrine glands, functions as a barrier. It separates our internal organs from potentially harmful toxins in the external environment.
Organization can also be found at the microscopic level, with the cell membrane acting as a barrier between the intracellular environment separate from the extracellular environment.
Metabolism is the process of consuming food and using it for energy and maintenance.
It is made up of two types of reactions:
This is the process of combining small molecules into larger ones.
It requires energy.
The result of anabolism is usually referred to as a 'macromolecule'.
This is the process of breaking down large molecules into smaller ones.
It releases energy.
adenosine triphosphate (ATP) is a chemical compound used by cells to store and release energy.
The cell uses anabolism to synthesize ATP, this stores energy
ATP molecules can then be moved to where they are needed
The cell then uses catabolism to break down the ATP and release energy
Responsiveness can be split into internal and external.
E.g. sweating in response to increased body temperature.
E.g. moving towards sources of food and water, or moving away from danger.
Movement can be found at all the levels of organization:
Movement of water, carbon dioxide, and other molecules
Movement of cells (blood, for example) through the body
Movement of tissues, such as muscle contraction
Movement of organs, and organ systems, e.g. to move food through your digestive system
Movement of an entire organism, e.g. walking or running
Development encompasses changes in the body, such as:
A cell changing from one type to another (usually a more specialized type)