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Human Physiology Bio 5 Denise Lim, Instructor 1 ParScore Scantrons for Lecture Tests z Orange, 8.5" X 11" z Do not wait until the day of the exam to buy them 2 Use Your Textbook Wisely Glossary/Index Concept Reviews (Blue Headings) "Focus On…” in Chapter 1 – Concept Mapping – Graphing Concept Checks – (Answers in Appendix A) Running Problems (case studies) Chapter Summaries Review Questions (Answers in Appendix A) Appendix B: Physics and Math basics 3 Some other words of advice Manage your time well Pay attention to detail Learn to be a good communicator Be professional 4 Introduction Chapter 1 What is Physiology? The integration of function across many levels of organization 5 Organization: small to big Atoms Molecules Cells Tissues Organs Organ systems 6 Function and Mechanism: "Why" versus "How" "Why" = Purpose "How" = Mechanism Need to understand both purpose and mechanistic, but focus on mechanism 7 Why is physiology so hard to study? Complexity – Conditions both inside and outside the body constantly change – Interplay between body systems change as conditions change Variation between individuals – Genetic predisposition, life style Safety, ethics – Investigative methods can be invasive 8 Important physiological themes Structure/Function relationships Energy –Metabolism Communication coordinates function Homeostasis & Regulation –Maintaining the constancy or stability of the internal environment within a range of tolerance 9 Homeostasis is maintained through mass balance and mass flow What goes in must go out What is lost must be replaced Fig. 1.5, pg. 11 10 Flow of exchange between the body’s external and internal environment Fig. 1.4, pg 11 11 Local versus longdistance control of homeostasis Fig. 1-9, pg. 14 Local response: intrinsic control Reflex response: extrinsic control 12 Homeostasis depends on communication and feedback Stimulus Receptor or sensor – Detects the stimulus Integrating center determines setpoint Effector produces response Fig. 1-10, pg. 15 13 Activity 1 14 Negative feedback counteracts the stimulus, maintains conditions within a range around a setpoint (range of tolerance) Fig. 1-11, pg. 16 15 Example: blood glucose Glucose levels drop after fasting: hungry Glucose rises after a meal Insulin brings levels back to setpoint May overshoot Fig. 22-19, pg. 716 16 Glucose Homeostasis Stimulus – Increased blood glucose Receptor – Beta cells in pancreas Afferent Pathway – ATP production increases when more glucose is available Integrating Center – Pancreas: releases insulin when ATP in beta cells is high Efferent Pathway – Insulin Effector – Liver and muscle cells: insulin triggers glucose uptake Response – Decreases blood glucose 17 Positive feedback amplifies body’s response; NOT homeostatic Inflammatory response Childbirth Fig. 1-12b, pg. 16 18 Figure 1.12 A positive feedback loop Baby drops lower in uterus to initiate labor Cervical stretch causing stimulates Push baby against cervix Oxytocin release Positive feedback loop causes Uterine contractions Delivery of baby stops the cycle Fig. 1.13, pg 17 HCl production in stomach Presence of food in stomach activates pepsin Emptying stomach shuts it off 20