The Human Body and Orientation

1. The Human Body and Orientation Chapter 1 Pg 1-21

2. Anatomy and physiology • Subdivisions of biology that describe how our bodies are put together and how they work • Emphasizes the structure and function relationships • Surface area/allows gas exchange

3. Levels of organization

4. Organ System Overview • Integumentary • Skeletal • Muscular • Nervous • Endocrine • Cardiovascular • Lymphatic • Respiratory • Digestive • Urinary • reproductive

5. Integumentary • Forms external body covering

6. Skeletal • Protects and supports body organs; acts as a framework

7. Muscular • Allows for movement

8. Nervous • Responds to internal and external changes and activates appropriate muscles and glands

9. Endocrine • Contains glands that secrete hormones to allow for metabolism, homeostasis, reproduction, growth, etc….

10. Cardiovascular • Transports oxygen, carbon dioxide, wastes, and nutrients via the blood through the body

11. Lymphatic • Transports fluid from blood vessels back to the blood, disposes of debris, houses white blood cells to fight off infection

12. Respiratory • Allows for gas exchange of oxygen and carbon dioxide

13. Digestive • Breaks down food into useable units to be absorbed by blood and eliminates undigestible food stuff

14. Urinary • Eliminates nitrogenous wastes from body and regulates water, electrolytes, and pH of the blood.

15. Reproductive • Allows for the production of offspring

16. Homeostasis • Describes the body’s ability to maintain relatively stable internal conditions even though the outside environment is constantly changing. • homeo=the same stasis=standing still • Dynamic equilibrium

18. Homeostatic Control Mechanisms • Accomplished primarily by the nervous and endocrine system via electrical signals and/or hormones • 3 components: • 1. Receptor, which responds to stimuli sends input to the • 2. Control center via afferent pathway and analyzes information and determines appropriate response or action. This is acted out by the • 3. Effector, which relays the output response from control center that came via the efferent pathway. The results of the response feed back to influence the stimulus

19. Negative Feedback Mechanism • Negative feedback depresses the stimulus so that the whole control mechanism is shut off • Most homeostatic control mechanisms are negative feedback mechanisms!!!! • Ex) a home heating system connected to a thermostat, and body regulation of temperature, heart rate, blood pressure, breathing rate, and blood levels of sugar, oxygen, carbon dioxide, and minerals

20. Negative Feedback Example • Home heating system connected to a thermostat: Thermostat contains both the receptor and the control center • If thermostat is set at 68⁰F, the heating system (effector) will be triggered ON when the house temperature drops below that setting • As the furnace produces heat, the air is warmed. When the temperature reaches 68 ⁰ F or slightly higher, the thermostat sends a signal to shut off the furnace

21. Positive Feedback • Positive feedback mechanisms increase the original disturbance (stimulus) and pus the variable farther from its original value • Positive feedback mechanisms are very rare in the body and occur as a result of events that occur explosively and do not require continuous adjustments • Ex) blood clotting and the birth of a baby

22. Homeostatic imbalances • Homeostasis is so important that most diseases can be regarded as a result of its disturbance, a condition known as homeostatic imbalance. • These disturbances increase with age as a result of body organs becoming less efficient • Pay attention to such conditions while using this text, they will be marked with a triangular symbol ∆

23. Review • Read over summary pg 22 & 23 • Complete all review questions • Write in complete sentences Formulate responses for the “At the Clinic” scenarios in the event you encounter them again