Human Physiology Chapter 1 Introduction PDF

Human Physiology, An Integrated Approach 8th Edition Chapter 1 Introduction to Physiology Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Chapter 1 Outline 1.Physiology is an Integrative...

Human Physiology, An Integrated Approach 8th Edition Chapter 1 Introduction to Physiology Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Chapter 1 Outline 1.Physiology is an Integrative Science 2.Function and Mechanism 3.Themes in Physiology 4.Homeostasis 5.Control Systems and Homeostasis 6.The Science of Physiology Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Learning Outcomes 1.Define physiology. 2.List the levels of organization from atoms through organism. 3.Name the 10 physiological organ systems of the body and give their functions. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.1 Physiology is an Integrative Science Physiology Defined Study of the normal functioning of a living organism and its component parts – Includes all its chemical and physical processes – Closely related to anatomy Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.1 Physiology is an Integrative Science Levels of Organization 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 PHYSIOLOGY ECOLOGY CELL MOLECULAR BIOLOGY BIOLOGY CHEMISTRY Organ Populations of Ecosystem of Atoms Molecules Cells Tissues Organs Organisms Biosphere systems one species different species Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.1 Physiology is an Integrative Science Organ System Integration FIG. 1.2 Organ Systems of the Human Body and their Integration System Name Includes Representative Functions The Integration between Systems of the Body Circulatory Heart, blood Transport of materials between all Integumentary System vessels, blood cells of the body Respiratory Digestive Stomach, Conversion of food into particles system intestine, that can be transported into the liver,pancreas body; elimination of some wastes Nervous system Endocrine Thyroid gland, Coordination of body function adrenal gland through synthesis and release of regulatory molecules Immune Thymus, spleen, Defense against foreign Endocrine lymph nodes invaders system Digestive system Integumentary Skin Protection from external Circulatory environment system Musculoskeletal Skeletal mus- Support and movement cles, bone Nervous Brain, spinal Coordination of body function cord through electrical signals and release of regulatory molecules Musculoskeletal system Urinary Reproductive Ovaries and Perpetuation of the species system uterus, testes Reproductive system Respiratory Lungs, airways Exchange of oxygen and carbon dioxide between the internal and external environments This schematic figure indicates relationships between Urinary Kidneys, bladder Maintenance of water and systems of the human body. The interiors of some Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved solutes in the internal hollow organs (shown in white) are part of the environment; waste removal external environment. Chapter 1 Outline 1.Physiology is an Integrative Science 2.Function and Mechanism 3.Themes in Physiology 4.Homeostasis 5.Control Systems and Homeostasis 6.The Science of Physiology Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Learning Outcomes 4.Distinguish between mechanistic explanations and teleological explanations. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.2 Function and Mechanism Function explains the “why” – Teleological approach Process or mechanism describes the “how” – Mechanistic approach Example: Red Blood Cells – Teleological: Why do red blood cells transport oxygen? ▪“Because cells need oxygen and red blood cells bring it to them.” – Mechanistic: How do red blood cells transport oxygen? ▪“Oxygen binds to hemoglobin molecules contained in the red blood cells.” Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Mapping Organizational tool for relationships and processes Structure/function maps –Relationship between anatomical structures and their functions –Atoms, molecules, cells, tissues, and organs Process maps or flow charts –Diagram processes in sequence Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.2 Function and Mechanism Figure 1.3 Structure/function maps SANDWICHES Outside components Fillings Dressings Breads Tortillas Wraps Vegetables Cheeses Meats and sauces Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.2 Function and Mechanism Figure 1.3 Process maps or flow charts 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 Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Chapter 1 Outline 1.Physiology is an Integrative Science 2.Function and Mechanism 3.Themes in Physiology 4.Homeostasis 5.Control Systems and Homeostasis 6.The Science of Physiology Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Learning Outcomes 5.List the four major themes in physiology. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.3 Themes in Physiology 1. Structure and function are closely related – Molecular interactions (Ch 2) – Compartmentation (Ch 3) 2. Living organisms need energy (Ch. 4ff) 3. Information flow coordinates body functions – Chemical signals (Ch 5 & 6) – Electrical signals (Ch 8-12) 4. Homeostasis maintains internal stability Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Chapter 1 Outline 1.Physiology is an Integrative Science 2.Function and Mechanism 3.Themes in Physiology 4.Homeostasis 5.Control Systems and Homeostasis 6.The Science of Physiology Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Learning Outcomes 6.Define homeostasis. What happens when homeostasis fails? 7.Name and describe the two major compartments of the human body. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.4 Homeostasis Homeo = like/similar statis = condition Maintenance of a relatively stable internal environment, despite changes in the internal and/or external environment Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.4 Homeostasis Critical variables – Environmental factors that affect cells – Materials for cells needs – Factors cells use to communicate with one another Involves interaction between ▪External environment ▪Extracellular fluid ▪Intracellular fluid Regulated within a range of values, not a single value Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.4 Homeostasis Loss of homeostasis is sensed by organism Attempt will be made to correct/restore homeostasis What happens when homeostasis is disturbed for prolonged periods? Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.4 Homeostasis Disease state or pathological condition –Failure to maintain homeostasis –Study of body functions in a disease state is called pathophysiology –Examples? Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  Organism in Figure 1.4 Homeostasis homeostasis External change Internal change Internal change results in loss of homeostasis Organism attempts to compensate Compensation fails Compensation succeeds Illness or disease Wellness Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.4 Homeostasis (a) Extracellular fluid is a buffer between cells and the (b) A box diagram represents the ECF, ICF, and external outside world. environment as three separate compartments. Cells contain intracellular fluid (ICF). External Extracellular Intracellular environment fluid (ECF) fluid (ICF) External Cells are surrounded Cells ECF environment by the extracellular fluid (ECF). The cell membrane separates cells from the ECF. ECF serves as buffer zone between outside world and ICF ECF needs to be kept relatively stable Figure 1.5 The body’s internal and external environments Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Learning Outcomes 8. Explain the law of mass balance and how it applies to the body’s load of a substance. 9. Distinguish between equilibrium and steady state. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  1.4 Homeostasis Figure 1.6 Mass balance (a) Mass balance in an open system (b) Mass balance in the body requires input equal to output. Input Input Output Intake through Excretion by intestine, lungs, kidneys, liver, skin lungs, skin To maintain constant level, BODY output must equal input. LOAD Metabolic Metabolism production to a new substance Law of Mass Balance Intake or Excretion or Output Existing + Mass balance = metabolic – metabolic body load production removal Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.4 Homeostasis Homeostasis Does Not Mean Equilibrium Dynamic steady state – Materials are constantly moving between two compartments Equilibrium – Implies composition of compartments are identical – But not the same as steady state Homeostasis attempts to maintain the dynamic steady state – Disequilibrium Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.4 Homeostasis Homeostasis Does Not Figure 1.7 Steady-state disequilibrium Mean Equilibrium ECF ICF 140 120 Concentration (mmol/L) 100 80 60 40 20 Na+ Cl– K+ Na+ Cl– K+ Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Chapter 1 Outline 1.Physiology is an Integrative Science 2.Function and Mechanism 3.Themes in Physiology 4.Homeostasis 5.Control Systems and Homeostasis 6.The Science of Physiology Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Learning Outcomes 10.List the three components of a control system and give an example. 11.Compare local control, long-distance control, and reflex control. 12.Explain the relationship between a regulated variable and its set- point. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.5 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 – Output signal Figure 1.8 A simple control system Input Integrating Output Response signal center signal Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  1.5 Control Systems and Homeostasis Figure 1.9 A comparison of local control and reflex control (a) Local control: In (b) Reflex control: In reflex control, cells at a local control, cells in distant site control the response. Local control restricted to a tissue or cell the vicinity of the change initiate the response. Brain Reflex control uses long-distance signaling evaluates the change and initiates a response. – Uses nervous and/or endocrine Brain Systemic change in blood pressure sensed here. LOCAL CHANGE Blood vessels REFLEX LOCAL RESPONSE RESPONSE is initiated by cells at a distant site. KEY Stimulus Integrating center Response Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.5 Control Systems and Homeostasis Reflex Steps In the aquarium example shown, the control box is set to maintain 1 Water temperature is below the setpoint. STIMULUS a water temperature of 30 ± 1 °C. Water temperature Feedback loop 2 Thermometer senses 1 is 25 °C. SENSOR temperature decrease. 3 Signal passes from sensor to control INPUT box through the wire. SIGNAL 2 Thermometer 4 Control box is Feedback programmed loop to respond to INTEGRATING temperature below CENTER Water 29 degrees. 7 temperature 3 increases. Wire 5 Signal passes through OUTPUT wire to heater. SIGNAL 4 Control box 5 6 6 Heater turns on. TARGET Wire to heater Heater 7 Water temperature RESPONSE increases. Figure 1.10 The steps in a reflex pathway Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  1.5 Control Systems and Homeostasis Most functions that maintain homeostasis have a Set-point, or normal value. The response loop that controls the function activates when the function moves outside a predetermined normal range. 32 Negative feedback turns Setpoint response loop off. of function Temperature (°C) 31 30 Normal range of function 29 Response loop turns on. 28 Time Figure 1.11 Oscillation around the setpoint Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Learning Outcomes 13.Compare negative feedback, positive feedback, and feedforward control. Give an example of each. 14.Explain what happens to set-points in biological rhythms and give some examples. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  1.5 Control Systems and Homeostasis Figure 1.12 Negative and positive feedback (a) Negative feedback: The response counteracts (b) Positive feedback: The response reinforces the stimulus, the stimulus, shutting off the response loop. sending the variable farther from the setpoint. Initial Initial stimulus stimulus Response Response Response loop shuts off. An outside factor is + Feedback loop required to shut off feedback loop. + Stimulus Stimulus Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved  1.5 Control Systems and Homeostasis Figure 1.13 A positive feedback loop Baby drops lower in uterus to initiate labor. Cervical stretch causing stimulates Push baby against cervix Oxytocin release + Feedback loop causes Uterine contractions Delivery of baby stops the cycle. Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved 1.5 Control Systems and Homeostasis Feedforward Control Negative feedback can help restore or maintain homeostasis, but cannot prevent the initial change (responds to it after it happens) Feedforward control anticipates change and responds accordingly to prevent disruption of homeostasis. – Saliva glands are activated by sight/smell of food Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved BioFlix: Homeostasis Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Biological Rhythms Result from Changes in a Setpoint Regulated variables create repeating patterns or cycles – Biorhythms – Daily circadian rhythm Adaptation to environmental conditions – Acclimatization occurs naturally – Acclimation in a laboratory setting Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Figure 1.14 Circadian rhythms in humans (a) Body temperature is lowest in the early morning and peaks in (b) Plasma cortisol is lowest during sleep and peaks shortly after the late afternoon and early evening. Data from W. E. Scales et al., awakening. Data from L. Weibel et al., Am J Physiol Endocrinol J Appl Physiol 65(4): 1840–1846, 1998. Metab 270: E608–E613, 1996. Dark Dark Dark 9:00 A.M. Dark Dark Dark Oral body temperature (°C) 37 20 Plasma cortisol (g/dL) 15 10 5 36 Midnight Noon Midnight Noon Midnight Midnight Noon Midnight Noon Midnight Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved Chapter 1 Outline 1.Physiology is an Integrative Science 2.Function and Mechanism 3.Themes in Physiology 4.Homeostasis 5.Control Systems and Homeostasis 6.The Science of Physiology Copyright © 2019, 2016, 2013 Pearson Education, Inc. All Rights Reserved