1. The Human Body: An Orientation

2. Figure 1.2f Organ System Overview Cardiovascular Cardiovascular –Transports materials in body via blood pumped by heart  Oxygen  Carbon dioxide  Nutrients  Wastes

3. Organ System Overview Lymphatic Lymphatic –Returns fluids to blood vessels –Cleanses the blood –Involved in immunity Figure 1.2g

4. Organ System Overview Respiratory Respiratory –Keeps blood supplied with oxygen –Removes carbon dioxide Figure 1.2h

5. Organ System Overview Digestive Digestive –Breaks down food –Allows for nutrient absorption into blood –Eliminates indigestible material Figure 1.2i

6. Organ System Overview Urinary Urinary –Eliminates nitrogenous wastes –Maintains acid-base balance –Regulates water and electrolytes Figure 1.2j

7. Organ System Overview Reproductive Reproductive –Produces offspring Figure 1.2k–l

8. Necessary Life Functions Maintain boundaries Maintain boundaries Movement Movement –Locomotion –Movement of substances Responsiveness Responsiveness –Ability to sense changes and react Digestion Digestion –Break-down and absorption of nutrients

9. Necessary Life Functions Metabolism—chemical reactions within the body Metabolism—chemical reactions within the body –Produces energy –Makes body structures Excretion Excretion –Eliminates waste from metabolic reactions

10. Necessary Life Functions Reproduction Reproduction –Produces future generation Growth Growth –Increases cell size and number of cells

11. Survival Needs Nutrients Nutrients –Chemicals for energy and cell building –Includes carbohydrates, proteins, lipids, vitamins, and minerals Oxygen Oxygen –Required for chemical reactions

12. Survival Needs Water Water –60–80% of body weight –Provides for metabolic reaction Stable body temperature Stable body temperature Atmospheric pressure Atmospheric pressure –Must be appropriate

13. Interrelationships Among Body Systems Figure 1.3

14. Homeostasis Homeostasis—maintenance of a stable internal environment Homeostasis—maintenance of a stable internal environment –A dynamic state of equilibrium Homeostasis is necessary for normal body functioning and to sustain life Homeostasis is necessary for normal body functioning and to sustain life Homeostatic imbalance Homeostatic imbalance –A disturbance in homeostasis resulting in disease

15. Figure 1.4 Change detected by receptor Stimulus: Produces change in variable Input: Information sent along afferent pathway to Receptor (sensor) Effector Variable (in homeostasis) Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis Control center Imbalance Output: Information sent along efferent pathway to activate

16. Maintaining Homeostasis The body communicates through neural and hormonal control systems The body communicates through neural and hormonal control systems –Receptor  Responds to changes in the environment (stimuli)  Sends information to control center

17. Maintaining Homeostasis –Control center  Determines set point  Analyzes information  Determines appropriate response –Effector  Provides a means for response to the stimulus

18. Feedback Mechanisms Negative feedback Negative feedback –Includes most homeostatic control mechanisms –Shuts off the original stimulus, or reduces its intensity –Works like a household thermostat

19. Feedback Mechanisms Positive feedback Positive feedback –Increases the original stimulus to push the variable farther –In the body this only occurs in blood clotting and during the birth of a baby