The Human Body: An Orientation

1. The Human Body: An Orientation

2. Organ System Overview • Cardiovascular • Transports materials in bodyvia blood pumped by heart • Oxygen • Carbon dioxide • Nutrients • Wastes Figure 1.2f

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

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

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

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

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

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

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

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

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

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

13. Interrelationships Among Body Systems Figure 1.3

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

15. Input:Informationsent alongafferentpathway to Controlcenter Output:Information sentalong efferentpathway to activate Effector Receptor (sensor) Changedetectedby receptor Response ofeffector feedsback toinfluencemagnitude ofstimulus andreturns variableto homeostasis Stimulus:Produceschangein variable Imbalance Variable(in homeostasis) Imbalance Figure 1.4

16. Variable(in homeostasis) Figure 1.4, step 1a

17. Stimulus:Produceschangein variable Imbalance Variable(in homeostasis) Imbalance Figure 1.4, step 1b

18. Receptor (sensor) Changedetectedby receptor Stimulus:Produceschangein variable Imbalance Variable(in homeostasis) Imbalance Figure 1.4, step 2

19. Input:Informationsent alongafferentpathway to Controlcenter Receptor (sensor) Changedetectedby receptor Stimulus:Produceschangein variable Imbalance Variable(in homeostasis) Imbalance Figure 1.4, step 3

20. Input:Informationsent alongafferentpathway to Controlcenter Output:Information sentalong efferentpathway to activate Effector Receptor (sensor) Changedetectedby receptor Stimulus:Produceschangein variable Imbalance Variable(in homeostasis) Imbalance Figure 1.4, step 4

21. Input:Informationsent alongafferentpathway to Controlcenter Output:Information sentalong efferentpathway to activate Effector Receptor (sensor) Changedetectedby receptor Response ofeffector feedsback toinfluencemagnitude ofstimulus andreturns variableto homeostasis Stimulus:Produceschangein variable Imbalance Variable(in homeostasis) Imbalance Figure 1.4, step 5

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

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

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

25. Feedback Mechanisms • 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