Cells organize into tissues, which then organize into organs that work together in organ systems. There are four main tissue types - epithelial, connective, muscle and nerve tissue. Epithelial tissues line body surfaces and internal cavities. Connective tissues bind other tissues together and provide structural support. Muscle tissues contract to cause movement. Nerve tissues transmit electrical signals to coordinate body functions. Organs contain multiple tissue types that work together to perform specific functions, and organ systems group related organs to carry out major processes like digestion and respiration.

1. Levels of OrganizationBiology Lecture 1 11-16-09

2. Chapter 4-3 Vocabulary Colonial Organism Organ Organ System Tissue

3. Section 4-3 Multicelluar Organization Most cells specialized to perform one or a few function Due to specialization: Cells of multicellular organisms depend on other cells in the organism

4. Levels of Structural Organization Atoms Molecule Organelle Cell Tissue Organ Organ System Organism

5. Tissues Cells that are organized into groups that carry out a specific function Examples: Epithelial tissue – sheets of closely packed cells Skin Connective tissue – Loosely scattered cells Muscle tissue – Cells that pull against each other Nerve tissue – Cells that transmit signals

6. Epithelial Tissue

7. A Classification of Connective Tissues

8. Muscle Tissue

9. Muscle Tissue

10. Muscle Tissue

11. Neural Tissue

12. Organs Several types of tissues that interact to perform a specific function All organisms have organs except most simple

13. Organ Systems Groups of organs that work together to perform a set of related tasks(need each other) Examples: 11 Systems in the Human Body Cardiac Nervous Skeletal Muscular Digestive Reproductive Immune Respiratory Excretory Endocrine Lymphatic