Chapter 1 Introduction to Physiology 2013 Pearson Education Inc About This Chapter Physiology is an integrative science Function and mechanism Themes in physiology Homeostasis Control systems and homeostasis The science of physiology 2013 Pearson Education Inc Definition of Physiology What is physiology Father of medicine Hippocrates The healing power of nature Physiology defined as Aristotle Knowledge of nature study of the functions and processes of living organisms Physiology Is an Integrative Science Integration of function across many levels of organization Complex systems have emergent properties 2013 Pearson Education Inc Moving Beyond the Genome Genomics Proteomics Study of all of the genomes of an organism Human Genome Project Study of all of the proteins of an organism The Physiome Project Molecular cellular and physiological information Translational research 2013 Pearson Education Inc Levels of Organization Physiology defined Study of the normal functioning of a living organism and its component parts Includes all its chemical and physical processes Organization of life The cell is the smallest unit of structure capable of carrying out all life processes Atoms molecules cells tissues organs organ systems and organisms 2013 Pearson Education Inc Figure 1 1 Levels of organization and the related fields of study PHYSIOLOGY ECOLOGY CHEMISTRY MOLECULAR BIOLOGY CELL BIOLOGY Atoms Molecules Cells Tissues Organs Organ systems Organisms Populations of one species Ecosystem of different species Biosphere Organ Systems in Review Integumentary Musculoskeletal Respiratory pulmonary Digestive gastrointestinal Urinary renal Reproductive Circulatory cardiovascular Nervous Endocrine Immune 2013 Pearson Education Inc Table 1 1 Organ Systems of the Human Body and their Integration Organ Systems in Review The integration between systems of the body Figure 1 2 Mapping Organizational tool for relationships and processes Schematic diagram of structure and function Atoms molecules cells tissues and organs Flow charts Diagram processes in sequence 2013 Pearson Education Inc Figure 1 2a Types of maps SANDWICHES Outline components Fillings Breads Tortillas Wraps Vegetables Cheeses Meats Dressings and sauces A map showing structure function relationships Figure 1 2b Types of maps Person working outside on a hot dry day Loses body water by evaporation Body fluids become more concentrated Internal receptors sense change in internal concentration Thirst pathways stimulated Person seeks out and drinks water Water added to body fluids decreases their concentration A process map or flow chart Function Versus Process Function explains the why Teleological approach significance Process or mechanism describes the how Mechanistic approach explains the process Red blood cell example Because cells need oxygen and red blood cells bring it Oxygen binds to hemoglobin molecules contained in the to them red blood cells 2013 Pearson Education Inc Themes in Physiology Structure and function are closely related Molecular interactions Compartmentation Living organisms need energy Information flow coordinates body function Homeostasis maintains internal stability 2013 Pearson Education Inc Table 1 2 Biology Concepts Homeostasis Regulation of the body s internal environment Keeping internal environment stable Interaction between Outside world Extracellular fluid Intracellular fluid 2013 Pearson Education Inc Homeostasis External or internal change Loss of homeostasis Sensed by organism Physiological attempt to correct Dynamic steady state Not the same as equilibrium 2013 Pearson Education Inc Homeostasis Successful compensation Homeostasis reestablished Failure to compensate Disease Study of failure to compensate is pathophysiology 2013 Pearson Education Inc Figure 1 3 Homeostasis Organism in homeostasis External change Internal change Internal change results in loss of homeostasis Organism attempts to compensate Compensation fails Compensation succeeds Illness or disease Wellness Figure 1 4 The body s internal and external environments Cells contain intracellular fluid ICF The cell membrane separates cells from the ECF Cells are surrounded by the extracellular fluid ECF Cells ECF External environment Extracellular fluid ECF Intracellular fluid ICF FIGURE QUESTION Put a on the cell membrane of the box diagram Figure 1 5 Mass balance in an open system Input Input Intake through intestine lungs skin Metabolic production BODY LOAD Output Excretion by kidneys liver lungs skin Metabolism to a new substance To maintain constant level output must equal input Law of Mass Balance Output Mass balance Existing body load Intake or metabolic production Excretion or metabolic removal Mass balance in an open system Mass balance in the body Figure 1 6 The body compartments are in a dynamic steady state but are not at equilibrium ECF ICF L l o m m n o i t a r t n e c n o C 140 120 100 80 60 40 20 Na Cl K Na Cl K Control Systems and Homeostasis Regulated variables are kept within normal range by control mechanisms Keeps near set point or optimum value Control systems local and reflex Input signal Integrating center controller integrates incoming info and initiates appropriate response Output signal 2013 Pearson Education Inc Figure 1 7 A simple control system Input signal Integrating center Output signal Response Figure 1 8 A comparison of local and reflex control Brain evaluates the change and initiates a response Brain In local control cells in the vicinity of the change initiate the response LOCAL CHANGE LOCAL RESPONSE Blood vessels Systemic change in blood pressure sensed here In reflex control cells at a distant site control the response REFLEX RESPONSE is initiated by cells at a distant site KEY Stimulus Integrating center Response Control Systems and Homeostasis Local control Reflex control Long distance pathway Uses nervous and or endocrine systems Response loop Stimulus sensor input signal integrating center output signal target response Feedback loop requires outside factor to shut off cycle Negative feedback stabilizes variable Positive feedback reinforces stimulus Feedforward control anticipates change 2013 Pearson Education Inc Figure 1 9 Steps in the response loop of a reflex control pathway Water temperature is 25 C Feedback loop Thermometer Wire Control box Wire to heater Heater Water temperature increases Reflex steps Water temperature is below the setpoint STIMULUS Thermometer senses temperature decrease SENSOR