Anatomy - Levels of Organization

Atoms

Smallest. Made of subatomic particles: electrons, protons, neutrons. e.g. Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus

Molecules

Made of bonded atoms.

4 types: Sugars, Ammino acids, Fatty acids, Nucleotides.

Macromolecules

Made of chains of molecules.

4 types: Carbohydrates, Proteins, Lipids, Nucleic acids.

Organelles

Made of macromolecules. e.g. Cell membrane, Mitochondria, Nucleus, etc.

Cells

Made of organelles. e.g. Neurons, Muscle cells, etc.

Tissues

Made of two or more cell types working together to perform a common function.

4 types: Epithelial, Nervous, Connective, Muscle.

Organs

Made of two or more tissue types working together to perform a common function. e.g. Heart, Lungs, Kidneys, etc.

Organ System

Made of two or more organs working to preform common function. 11 total organ systems in human body. e.g. Nervous, Respiratory, Digestive, etc.

Organism

Made of organ systems working to preform a common function.