1. Intro to Animal Structure & Function Ch. 40

2. Cellular Organization The way that cells are organized Tissues: similar cells performing a common function Four types of animal tissue: Epithelial (outer skin, mucous membranes) Connective (Blood, cartilage, bone) Nervous (Neurons) Muscle (Contractile tissue) Organs: group of different tissues working together to perform a job (ex. Heart) Organ System: 2+ organs working together to perform a job. (Circulatory system)

3. Cells  Tissue  Organ  Organ System

4. Regulating the Internal Environment The purpose of most animal systems is to aid in keeping homeostasis Homeostasis: stable internal conditions. Slight fluctuations, but mostly stable Negative Feedback: change in the variable being monitored triggers the control mechanism to counteract further change in the same direction Results in a fairly stable environment Most homeostatic mechanisms in animals use negative feedback

7. Positive Feedback: a change in a variable that triggers mechanisms that amplify rather than reverse the change. Ex: During childbirth, pressure from the baby’s head stimulates contractions, which cause even greater pressure, which in turn stimulates more contractions, etc. Positive feedback has an amplifying effect

8. Endothermic: Bodies warmed by heat generated by metabolism Body temperature must be maintained at a certain level to sustain life Also called “homeotherms” or “warm-blooded” Ectothermic: Do not produce enough metabolic heat to have an effect on body temperature. Obtain body heat from environment Ex: amphibians, reptiles, fish Also called “poikilotherms” or “cold-blooded”

9. Some ways that animals control body temperatures: Behavior: Hibernation, Daytime/Nighttime activity Metabolism: metabolic activity such as muscle contraction generates heat Evaporation: sweating and panting loses heat. Adjusting Surface Area: By controlling the amount of blood sent to the body’s extremities heat can be lost or absorbed. Animals can control blood flow with vasodilation or vasoconstriction.