What is the organization of the body?

Organization of Body Parts 
The structure of the body can be studied at different levels of organization. First, all substances, including body parts, are composed of chemicals made up of submicro­scopic particles called atoms. The atoms most frequently found in the body are carbon, hydrogen, oxygen, and ni­trogen. Atoms join together to form a molecule, which can join with other molecules to form macromolecules. The macromolecules in cells are called biomolecules in this text. For example, the molecules called amino acids join to­gether to form a biomolecule called protein. Muscles con­tain a significant amount of protein; therefore, meat is a rich source of this basic nutrient.
Proteins and also fats contribute to the makeup of the cell, the basic unit of all living things. Cells are the smallest living portion of any organism, and it is at the cellular level that health and disease are best understood. Within cells are organelles, tiny membranous structures that perform cell functions. For example, the or­ganelle called the nucleus is especially concerned with cell reproduction; another organelle called the mitochondrion supplies the cell with energy.
Cells are found in tissues, and tissues make up organs. A tissue is composed of similar types of cells and performs a specific function. An organ is composed of several types of tissues and performs a particular function within an organ system. For example, the stomach is an organ and is a part of the digestive system. It has a specific role in this system, in which the overall function is to supply the body 'dth the nutrients needed for growth and repair. The other systems of the body also have specific functions.
All of the body systems together make up the organism -in this case, the human being. Human beings are com­plex animals, but this complexity can be broken down and
studied at ever simpler levels. Each simpler level is organ­ized and constructed in a particular way.
The body has levels of organization that progress from atoms to molecules. macromolecules (biomolecules), cells, tissues. organs. organ systems. and finally, the organism.

Posted in Human Anatomy and Physiology