1. Chapter 1 Homeostasis Recall the concept and components of homeostatic systems, describing how cells, tissues, organs and organ systems maintain important physiological set points. This will be measured by quiz and exam scores.

2. Outline Physiology Levels of organization Basic Cell function Tissues Body systems Homeostasis

3. Physiology Study of body functions Two processes explain body functions –Teleological Explanations are in terms of meeting a bodily need –Mechanistic Explanations are in terms of cause and effect sequences –Body is viewed as a machine

4. Physiology is the study of body functions Physiologists explain body function in terms of cause-and-effect sequences Two approaches are used to explain events that occur in the body: –The purpose of a body process –The underlying mechanism Anatomy is the study of structure Physiology and anatomy are interrelated because functions depend on structure Structure-Function relationships of the body Examples: Heart receiving and pumping blood Teeth tearing and grinding food

5. Levels of Organization-Cells

6. Basic Cell Functions Obtain nutrients and oxygen from surrounding environment Perform chemical reactions that provide energy for the cell Eliminate carbon dioxide and other wastes to surrounding environment Synthesize needed cellular components Control exchange of materials between cell and its surrounding environment Sensing and responding to changes in surrounding environment Reproduction –Exception Nerve cells and muscle cells lose their ability to reproduce during their early development

7. Why Study Cells? Stem Cell Research (pg 10) 5 minutes

8. Tissues Groups of cells with similar structure and specialized function Four primary types of tissues –Muscle tissue –Nervous tissue –Epithelial tissue –Connective tissue

9. Tissues Muscle tissue –Specialized for contracting and generating force –Three types of muscle tissue Skeletal muscle –Moves the skeleton Cardiac muscle –Pumps blood out of the heart Smooth muscle –Encloses and controls movement of contents through hollow tubes and organs Connective tissue –Cells dispersed in a matrix –Connects, supports, anchors tissue

10. Tissues Nervous tissue –Consists of cells specialized for initiating and transmitting electrical impulses –Found in brain, spinal cord, and nerves Epithelial tissue –Consists of cells specialized for exchanging materials between the cell and its environment –Organized into two general types of structures Epithelial sheets Secretory glands

11. Fig. 1-4a, p. 7

12. Sweat gland duct in the skin. LM X5. Credit: © Carolina Biological/Visuals Unlimited 318237

13. Simple Squamous Epithelium. LM X75. Credit: © Carolina Biological/Visuals Unlimited 310887

14. Microscopic technique series - Cheek cells. Phase view. LM X75. Credit: © David Phillips/Visuals Unlimited 308777

15. Stratified squamous epithelium from mouth mucosa. H&E stain. LM X100. Credit: © G.W. Willis, MD/Visuals Unlimited 301193

16. Credit: © Carolina Biological/Visuals Unlimited 310845

17. Human pseudostratified columnar epithelium lining the bronchus of the lung. H&E stain. X180. Credit: © G.W. Willis, MD/Visuals Unlimited 164740

18. Areolar (loose) connective tissue. LM X60. Credit: © Carolina Biological/Visuals Unlimited 317178

19. Hyaline cartilage. X64. Credit: © Dr. Fred Hossler/Visuals Unlimited 98769

20. Collagen or dense connective tissue. X155. Credit: © Dr. David Phillips/Visuals Unlimited 98964

21. Reticular fibers, silver preparation. X100. Credit: © Dr. Richard Kessel/Visuals Unlimited 98990

22. Human unilocular (white) fat and adipose (adult fat). H&E stain. LM X100. Credit: © G.W. Willis, MD/Visuals Unlimited 164732

23. Bone section showing osteocytes in lacunae arranged in concentric circles surrounding Haversian canals. LM X75. Credit: © Carolina Biological/Visuals Unlimited 319245

24. Organs Consist of two or more types of primary tissues that function together to perform a particular function or functions Example –Stomach Inside of stomach lined with epithelial tissue Wall of stomach contains smooth muscle Nervous tissue in stomach controls muscle contraction and gland secretion Connective tissue binds all the above tissues together

25. Levels of Organization-Organs Organs are combinations of two or more types of tissues that function together An example is the stomach: –Lined with epithelial tissue –Wall contains smooth muscle and nervous tissues –Connective tissue binds various tissues together

26. Body Systems Groups of organs that perform related functions and interact to accomplish a common activity essential to survival of the whole body Do not act in isolation from one another Human body has 11 systems

27. Body Systems Circulatory System Digestive System Respiratory System Urinary System Skeletal System Muscular System Integumentary System Immune System Nervous System Endocrine System Reproductive System

28. Information from the external environment relayed through the nervous system O2O2 CO 2 Urine containing wastes and excess water and electrolytes Nutrients, water, electrolytes Feces containing undigested food residue Sperm leave male Sperm enter female EXTERNAL ENVIRONMENT BODY SYSTEMS RESPIRATORY SYSTEM NERVOUS SYSTEM URINARY SYSTEM DIGESTIVE SYSTEM REPRODUCTIVE SYSTEM Exchanges with all other systems CIRCULATORY SYSTEM Exchanges with all other systems MUSCULAR AND SKELETAL SYSTEM IMMUNE SYSTEM INTEGUMENTARY SYSTEM ENDOCRINE SYSTEM Body systems maintain homeostasis Keeps internal fluids in Keeps foreign materials out HOMEOSTASIS Homeostasis essential for cell survival CELLS Cells make up body system Enables the body to interact with the external environment Protects against foreign invaders Regulate What contribution does each system make to whole body homeostasis?

29. Homeostasis vs. Allostasis Homeostasis –ideal set point through local regulatory mechanism Claude Bernard 1865 and Walter Cannon 1926 –ex. Kidneys figure this out and decrease fluid output Allostasis: –The brain coordinating body-wide changes often including changes in behavior. –“ remaining stable by being variable” –Sterling and Eyer 1988. Sterling, P.; Eyer, J. (1988). "Allostasis: A new paradigm to explain arousal pathology". In Fisher, S.; Reason, J. T. Handbook of life stress, cognition, and health. Chicester, NY: Wiley.

30. Concept of Homeostasis Homeostasis defined as maintenance of a relatively stable internal environment –Does not mean that composition, temperature, and other characteristics are absolutely unchanging Homeostasis is essential for the survival of each cell Each cell helps maintain the internal environment shared by all cells Factors maintained homeostatically: –concentration of nutrients –concentration of O 2 and CO 2 –concentration of waste products –pH –concentrations of water, salt, and other electrolytes –volume and pressure –temperature

31. Fluid Compartments The fluid inside the cell is intracellular fluid (ICF) The fluid outside the cells is extracellular fluid (ECF) –ECF is the body’s internal environment Consists of the plasma and interstitial fluid Most body cells are not in direct contact with the external environment Cell survival depends on maintaining a relatively stable internal fluid environment

32. Homeostatic Control Systems In order to maintain homeostasis, control system must be able to –Detect deviations from normal in the internal environment that need to be held within narrow limits –Integrate this information with other relevant information –Make appropriate adjustments in order to restore factor to its desired value

33. Homeostatic Control Systems Control systems are grouped into two classes –Intrinsic controls Local controls that are inherent in an organ –Extrinsic controls Regulatory mechanisms initiated outside an organ Accomplished by nervous and endocrine systems

34. Homeostatic Control Systems Feedforward –Term used for responses made in anticipation of a change Feedback –Refers to responses made after change has been detected –Types of feedback systems Negative Positive

35. Homeostatic Control Systems Negative feedback system –Primary type of homeostatic control –Opposes initial change –Components Sensor –Monitors magnitude of a controlled variable Control center –Compares sensor’s input with a set point Effector –Makes a response to produce a desired effect

36. Homeostatic Control Systems Positive feedback system –Amplifies an initial change –Do not occur as often as negative feedback system –Example Uterine contractions become increasingly stronger until the birth of the baby Pathophysiology refers to abnormal functioning of the body associated with disease When a homeostatic disruption becomes so severe that it is no longer compatible with survival, death results