1. Introduction to Anatomy – Lesson 2 TSWBAT list the levels of structural organization.

2. Levels of Structural Organization Chemical (or molecular level) Cellular Tissue Organ Organ System Organism

3. Levels of Structural Organization 1. Chemical – Atoms (smallest stable units of matter) combined to form molecules (complex shapes of two or more atoms). 2. Cellular – Molecules interact to form organelles. Organelles are components of cells (smallest living units in the body). Example – cardiac muscle cells 3. Tissue – Groups of similar cells that have a common function. (example – cardiac muscle tissue)

4. Levels of Structural Organization 4. Organ – A structure that is composed of two or more tissue types and performs a specific function for the body (example – heart: cardiac muscle tissue and smooth muscle tissue). 5. Organ System – A group of organs that cooperate to accomplish a common purpose (example – cardiovascular system; heart, blood, blood vessels).

5. Levels of Structural Organization 6. Organism – Made up of the organ systems. Highest level of structural organization (example – human).

6. Chemical level Atoms combine to form molecules 1 2 3 4 Cellular level Cells are made up of molecules Tissue level Tissues consist of similar types of cells 5 Organ system level Organ systems consist of different organs that work together closely Organ level Organs are made up of different types of tissues 6 Organismal level The human organism is made up of many organ systems Atoms Molecules Smooth muscle cell Smooth muscle tissue Connective tissue Smooth muscle tissue Epithelial tissue Blood vessel (organ) Heart Blood vessels Cardiovascular system Levels of Structural Organization Figure 1.1

7. 2. Which levels of structural organization are you unable to see with your naked eye? 3.Which level of structural organization is composed of two or more different types of tissues that work together to perform a specific function? 4. How are organs and tissues different? 1. Two or more atoms join together to form what organizational structures?