Chapters 1_2_5


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CHAPTER 1: INTRODUCTION TO PHYSIOLOGY PDBIO 362 I. Homeostasis – most cells in the body do require an environment that is held within pretty narrow specifications A. How does this happen: 1. Only small percentage of cells are actually in contact with the external environment B. Extracellular fluid 1. Surrounds all cells (about 1/3 of total body volume) a) (intracellular fluid is what is inside cells – contains most of the body’s water) b) Creates a buffer zone from external world C. Body attempts to maintain internal environment by correcting any changes D. Failure to maintain homeostasis leads to disruption of body function 1. Disruption leads to pathological conditions/disease states CHAPTER 2: Concentrations and Molarity (pp. 35-38) I. Solutions and Solutes A. Solutes = Substances that dissolve in liquid B. Solvents = Liquids that dissolve solutes C. Solution = Solute + solvent II. Not all molecules dissolve in aqueous solutions A. Water is the universal biological solvent B. Degree of solubility 1. Hydrophilic = Molecules that dissolve easily in water 2. Hydrophobic = Molecules that do not dissolve easily in water III. Ways to express the concentration of a solution A. Units used to express the concentration of a solution 1. Weight given in grams 2. # of molecules in moles 3. # of solute ions in equivalents 4. volume as liters or milliliters B. Mole = 6.02 X 10 23 atoms 1. Molarity = # of moles of solute per liter a) Example: glucose = C 6 H 12 O 6 (C=12, H=1, O=16) so (1) (6x12)+(12x1)+(6x16) = 180 (2) 1 molar solution of glucose = 180 grams of glucose in 1 liter of water C. Equivalents 1. How does this differ from molarity? a) Molarity of solution x number of charges on ion (1) Example: Ca 2+ has 2 charges D. Weight/volume and percent solutions 1. How to make a per cent solution a) Example: 10% solution = 10 parts solute / 100 parts total solution 2. Units: mg/mL; mg/dL; mg% IV. Concentration of hydrogen ions and pH units A. pH: power of hydrogen ions (H + ) (fig 2-15) 1. Concentration of H + determines body pH 2. pH = -log[H + ] (see Appendix A) 3. Acids = molecules that ionize and release a H + 4. Bases = molecules that combine with H + 5. Buffers in the body a) help prevent large changes in [H + ] CHAPTER 5 – MEMBRANE DYNAMICS 1
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I. Principles of mass balance and mass flow A. Mass balance: total amount of substance in the body = intake + production – output (Fig. 5-1) 1. If substance level is to remain balanced, any gain must be offset by an equal loss a) Examples: (1) Heat gain/loss (2) Oxygen/carbon dioxide levels (3) Water, salts, hydrogen ions 2. Major routes for loss from the body: a) Urinary and digestive systems b) Respiratory system c) Integumentary system 3. Sensors monitor gain and loss – homeostasis maintains balance B. Mass flow (or amount per minute [or time]) = concentration X volume flow 1. Example: 50g glucose per liter i.v. at 2 ml/min 2. Mass flow = [50g glucose/1000 ml x 2 ml/min] = 0.1 g glucose/min II. CELL MEMBRANES
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This note was uploaded on 05/09/2008 for the course PDBIO 362 taught by Professor Sudweeks during the Winter '08 term at BYU.

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