Structural levels of Organization

A&P Ch 1a

Chemical level

atoms→ molecules → organelles

Cellular Level

Cells (smallest unit of living things)

Tissue level

groups of similar cells that preform specific functions

Organ level

structures that contain 2+ types of tissues

Organ System

organs that work together to preform complex functions

Organismal level

all organ systems to make whole organism

3 rules

1. organ systems are designed to service cells

2. all cells depend on organ systems to meet survival needs

3. 11 total organ systems