Introduction to Physiology

1. Introduction to Physiology 1

2. 2. Levels of Organization • Physiology defined • Study of the functions and processes of living organisms- as seen under normal conditions. This is different from anatomy since it is the study of structure. • Organization of life • The cell is the unit of life • Cells, tissues, organs, organ systems, and organisms

3. 3. Levels of Organization Figure 1-1

4. 4. Organ Systems in Review • Integumentary-Skin, hair, nails. 7 functions main one is protection. • Musculoskeletal- Muscle and bone- main functions is movement and protection. • Respiratory- Lungs and respiratory tract- main function is gas exchange • Digestive-GI tract and accessory organs- main function is digestion to provide nutrion. • Reproductive and Urinary- genitals (primary and accessory) and urinary organs- main function is reproduction and excretion • Circulatory-Heart, blood vessels, blood. Main function is to deliver components needed by living cells and collect waste. • Nervous and Endocrine- Brain, nerves, and glands. Main function is to control body functions, responses, and information management. • Immune- white blood cells, lymphatic system, and other organs belonging to systems listed above. Main function is to protect the body from infection and promote healing.

5. 5. Organ Systems in Review The integration between systems of the body (immune system not shown) Figure 1-2

6. 6. Function versus Process • Function explains the “why” • Teleological approach- explains to you the functions. This approach can be used to relate different systems. • Process or mechanism describes the “how” • Mechanistic approach-explains the processes of how things work but doesn’t give a reason why. Incorporates principles of physics, chemistry, and biology. • Physiology integrates function and process. • Red blood cell example • Why do we have red blood cells? • How do red blood cells do this?

7. 7. Homeostasis (“a relatively constant environment”) • Environmental balance-despite the changes in the external environment the body is able to maintain a constant internal environment. Example- water balance • External-temperature, humidity, and other environmental factors affect our internal environment. • Internal-body temperature, hydration, pH balance, CO2/O2 levels and more are internal components that must be stable for cells to function properly. • Cell • Intracellular fluid-found inside the cells- it directly affects cell organelles. • Extracellular fluid-surrounds cells and serves as a buffer zone and changes as a result of overall body conditions.

8. 8. Factors Homeostatically Regulated • Concentration of nutrient molecules- nutrient molecules are used by the cell to produce energy • Concentration of O2 and CO2- oxygen is needed to produce energy. Carbon dioxide is a waste product of this process and must be removed to maintain pH • Concentration of waste products- accumulation of waste products causes toxic effects • pH- appropriate pH levels are required for proper nerve cell and enzyme function in the body. • Concetration of water, salt, and other electrolyte- regulation is essential for maintaining proper cell volume and function • Volume and Pressure- ultimately affect plasma levels needed for linking intra- & extracellular environments • Temperature- a narrow range allows for proper function to prevent slow down or impairment of protein function

9. 9. Homeostasis Relationships between an organism’s internal and external environments Protective cells allow for less diffusion than exchange cells do. Movement of intra- and extra cellular fluid happens at equal rates Figure 1-3

10. 10. Homeostasis and Controls • External or internal change-Because extracellular fluid influences the internal cell environment it must remain within the narrow range of normal values. • Physiological attempt to correct- when the normal ranges for extracellular fluid are not met compensatory mechanisms help to restore conditions. • Sensors, integrating center- certain organs in the body monitor internal conditions. • Response of cells and organs- a disruption of homeostasis triggers compensatory mechanism- example: thrist. • Loss of homeostasis- inability to restore a normal range environment.

11. Homeostasis and Controls • Successful compensation- discontinues triggered reponses, • Homeostasis reestablished- normal function is restored. • Failure to compensate • Pathophysiology- functioning under a state of disease • Illness- a pathological condition that may result from external or internal failure of normal processes • Death- occurs when homeostasis fails and cell life cannot be sustained.

12. Homeostasis and Controls Figure 1-4

13. Themes in Physiology • Homeostasis and control systems – process that maintain a stable environment using signals and a controller. • Biological energy - used for processes like transport and metabolism • Structure-function relationships • Molecular interactions – abilities of individual molecules to interact with each other greatly influences biological functions. • Compartmentation- uses boundaries or concentrated areas to promote specialization of a process. • Mechanical properties – cells have specific characteristics that facilitate function like elasticity, pumps, etc. • Communication- the flow of information through chemical and electrical signals. These themes will appear throughout the units and chapters.

14. The Scientific Method • A series of procedures used by scientist to explain and observation. • The explanation may lead to the formation of a theory or law • The steps of the scientific method may be followed in different order must commonly it is presented as follows.

15. Scientific Method

16. The scientific method • Observation – recognizing something has occurred • As one observes events there may be something that spikes your curiosity. You want to understand how or why it happens. • Question Formation – relates to observation • You create a question the reflects the observation and interest. • Research- exploration of alternative resources • You look up information gathered on the subject you are exploring. It may be previous research or well stablished information. • Hypothesis – possible explanation/answer to question. Educated guess. • After research and learning more you make an educated guess to explain your observation. This will be tested through experimentation.

17. The scientific method • Experimentation- testing the hypothesis through experiment • Experimental group vs. Control group -both groups are tested in identical conditions. They vary by only one variable- it is the factor that you think influences an outcome that either supports or rejects the hypothesis. b. Independent variable vs. Dependent variable - variables not -variables influenced by affected by others change in others c. Valid and reliable results - if multiple test give the same results and there are enough subjects or sample for results to be statistically supported, then results are valid and reliable.

18. Scientific Method • Agree with or create laws and theory • Scientific Law- uniform or constant feature of nature describing what happens in nature • Theory- widely accepted , plausible generalization about fundamental concepts in science that is supported by many experiments and explains why things happen in nature. • Conclusion and communication • You decide whether the results support or reject the hypothesis and share it with the scientific community • a. Inductive reasoning vs. deductive reasoning • Inductive- draw a conclusion from the sum of multiple results • Deductive- draw a conclusion after excluding mulitple possibilities

19. Summary • Organ systems • Structures and functions • Homeostatic balance • Integrative science • Four key themes • Scientific Method