1. Animal Structure and Function Organization of cells into systems that are specialized for particular functions. –Tissues- 4 general categories 1.Epithelial tissue 1.outer skin layers and internal protective coverings 2.Connective tissue 1.Bone, cartilage, blood 3.Nervous tissue 4.Muscle tissue

2. Animal Structure and Function Organ –A group of different tissues functioning together to perform a particular activity. –Example Heart –Consists of tissues from all four categories functioning together to pump blood through the body

3. Animal Structure and Function Organ system –Two or more organs working together to accomplish a particular task. –Example Digestive system –Coordinated activities of many organs Mouth, stomach, small intestine, large intestine, pancreas, and liver

4. Animal Structure and Function Homeostasis –Maintaining a stable, internal conditions within narrow limits –Negative feedback Sensing mechanism (receptor) –Detects a change in conditions beyond specific limits Control center (integrator) –Often a brain –Evaluates the change and activates a second mechanisms (effector) to correct the condition When the condition is corrected, the corrective action is discontinued.

5. Animal Structure and Function Positive feedback –An action intensifies a condition so that it is driven further beyond normal limits –Examples Labor contractions lactation