1. Unit 9-Anatomy and Physiology Chapter 30-Digestive and Excretory Systems

2. Chapter 30.1: Organization of the Human Body

3. Levels of Organization in the Body
- Cells
Are the basic unit of structure and function in an organism
Tissues
Are a group of cells that perform a single function

4. Levels of Organization in the Body
Four types of tissues:
Epithelial
Lines interior and exterior body surfaces
Connective
Supports and connects body parts
Nervous
Transmits nerve impulses
Muscle
Moves body parts

6. Levels of Organization in the Body
Organs
Are groups of different tissue types that work together to perform a single function or several related functions
Organ Systems
Are groups of organs that perform closely related functions

9. Homeostasis
Is the relatively constant internal physical and chemical conditions that organisms maintain despite changes in internal and external environments

10. Homeostasis Is maintained through feedback inhibition
Also called negative feedback
A stimulus produces a response that opposes the original stimulus
A thermostat is a good example
Room gets cooler
Heater turns on
Room gets warmer

11. Examples of Homeostasis
Body Temperature
Hypothalamus acts like a thermostat
Triggers the body to shiver when cold, and to sweat when hot
Blood Sugar
Blood sugar (glucose) rises after a meal
Too much blood sugar can damage organs
Body cells absorb glucose, and the liver stores glucose as glycogen
Blood sugar drops to a safe level