The human body is made up of different levels of organization from cells to tissues to organs to organ systems. Cells that work together form tissues, such as epithelial, nervous, muscle, and connective tissues. Two or more tissues working together form organs like the brain, lungs, and stomach. Organs that work together are organized into 11 major organ systems that maintain homeostasis, including the muscular, skeletal, digestive, respiratory, nervous, integumentary, endocrine, lymphatic, reproductive, circulatory, and urinary systems.

1. Human BodyLevels of Organization

2. ObjectivesDescribehow tissues, organs, and organ systems are related.

3. List 11 major organ systems.

4. Identify how organ systems work together to maintain homeostasis.HomeostasisThe many kinds of cells in your body help your internal environment stay stable.

5. The maintenance of a constant internal state in a changing environment is called homeostasis.4 Types of TissuesCells Form Tissues A group of similar cells working together forms a tissue. Your body has four main kinds of tissue.EpithelialNervousMuscleConnective

6. EpithelialCovers and protects underlying tissues.Examples – skin, inside of mouth/nose

7. NervousSends electrical signals throughout the bodyExamples – Nerves, Brain, Spinal cord

8. MuscularMade of cells that contract and relax to produce movementExamples – Biceps, quadriceps, tongue

9. ConnectiveJoins, supports, protects, insulates, nourishes and cushions organs and joints.

10. Tissues to OrgansTissues Form OrgansTwo or more tissues working together to carry out a specialized function form an organ.

11. Working TogetherOrgans Form Systems Organs that work together make up an organ system.