BIOH 370 1st editionLecture 30 Outline of Last Lecture Urinary System Day 4/ Fluid, Electrolyte, and Acid-Base BalanceI. Kidney StonesII. Urinary IncontinenceIII. Fluid CompartmentsIV. Water Balance and ECF OsmolalityV. Regulation of Water IntakeVI. Regulation (hormonal) of Renal Na and Cl Reabsorption After High Sodium IntakeVII. Fluid Compartments and Fluid Homeostasis ChartVIII. Influence of Other HormonesIX. Water Balance Disordersa. Dehydrationb. Hypotonic Hydration (water intoxication) Outline of Current Lecture Fluid, Electrolyte and Acid-Base Balance Lecture Day 2I. Treatment for Water Intoxication and DehydrationII. EdemaIII. Electrolyte ConcentrationIV. Extracellular vs. Intracellular FluidsV. Blood Electrolyte Imbalances ChartsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.VI. Acid-Base Balancea. Chart of Mechanisms to Maintain pH of Body Fluidsb. Buffer systems:i. Bicarbonate Buffer Systemii. Phosphate Buffer Systemiii. Protein Buffer Systemc. Physiological Buffering: Exhalation of CO2d. Renal Mechanisms i. Type A intercalated Cellsii. Type B intercalated Cellse. Acidosis Vs. AlkalosisCurrent LectureFluid, Electrolyte and Acid-Base Balance Lecture Day 2I. Treatment for Water Intoxication and Dehydration- Water Intoxication Treatment: use a hypertonic saline solution- not isosaline or hypotonic solution- Dehydration Treatment: give a normal saline solutionII. Edema: - Hindered fluid return occurs with an imbalance in colloidosmotic pressures, e.g., hypoproteinemia (¯ plasma proteins)o Fluids fail to return at the venous ends of capillarybedso Results from protein malnutrition, liver disease, or glomerulonephritis- Blocked (or surgically removed) lymph vesselso Cause leaked proteins to accumulate in IFo Colloid osmotic pressure of IF draws fluid from the bloodo Results in low blood pressure and severely impaired circulation- Atypical accumulation of IF fluid ® tissue swelling- Due to anything that increases flow of fluid out of the blood or hinders its returno Blood pressureo Capillary permeability (usually due to inflammatory chemicals) o Incompetent venous valves, localized blood vessel blockage o Congestive heart failure, hypertension, blood volumeIII. Electrolyte Concentration- Expressed in milliequivalents per liter (mEq/L), a measure of the number of electrical charges per liter of solutionmEq/L = ion concentration (mg/L) ´ # of electrical charges atomic weight of ion (mg/mmol) on one ion- For single charged ions (e.g. Na+), 1 mEq = 1 mOsm - For bivalent ions (e.g. Ca2+), 1 mEq = 1/2 mOsmIV. Extracellular vs. Intracellular Fluids:- Importance of electrolyte balanceo Controlling fluid movementso Excitabilityo Secretory activityo Membrane permeability- Each fluid compartment has a distinctive pattern of electrolytes- Difference in electrolytes in the ECF and ICF create a gradient for secondary active transport=important to keep balanced- ECFo All similar, except higher protein content of plasma Major cation: Na+ -not much in ICF due to Na/K ATPase pump Major anion: Cl–- ICF:o Low Na+ and Cl– Major cation: K+ Major anion HPO42–V. Blood Electrolyte Imbalances ChartsVI. Acid-Base Balance- pH affects all functional proteins and biochemical reactions- Normal pH of body fluidso Arterial blood: pH 7.4o Venous blood and IF fluid: pH 7.35o ICF: pH 7.0- Alkalosis or alkalemia: arterial blood pH >7.45- Acidosis or acidemia: arterial pH < 7.35- Most H+ is produced by metabolismo Phosphoric acid from breakdown of phosphorus-containing proteins in ECFo Lactic acid from anaerobic respiration of glucose o Fatty acids and ketone bodies from fat metabolism o H+ liberated when CO2 is converted to HCO3– in blood- Chart of Mechanisms to Maintain pH of Body Fluids- hierarchical order---- Buffer systems: Bicarbonate Buffer System Mixture of H2CO3 (weak acid) and salts of HCO3– (e.g., NaHCO3, a weak base) Buffers ICF and ECF The only important ECF buffer Phosphate Buffer System: Action is nearly identical to the bicarbonate buffer Components are sodium salts of:a. Dihydrogen phosphate (H2PO4–), a weak acidb. Monohydrogen phosphate (HPO42–), a weak base Effective buffer in urine and ICF, where phosphate concentrations are high Protein Buffer System: Intracellular proteins are the most plentiful and powerful buffers; plasma proteins are also important Protein molecules are amphoteric (can function as both a weak acid anda weak base)a. When pH rises, organic acid or carboxyl (COOH) groups release H+b. When pH falls, NH2 groups bind H+- Physiological Buffering: Exhalation of CO2 Respiratory system eliminates CO2 A reversible equilibrium exists in the blood:o CO2 + H2O « H2CO3 « H+ + HCO3– During CO2 unloading the reaction shifts to the left (and H+ is incorporated intoH2O) During CO2 loading the reaction shifts to the right (and H+ is buffered by proteins)Alveolus: foavors conversion from bicarbonate to CO2 + H20 so canbe exhaledIn tissues: favors conversion to bicarbonate to betransferred throughout body- Renal Mechanisms  Most important renal mechanisms Conserving (reabsorbing) or generating new HCO3– Excreting HCO3– Generating or reabsorbing one HCO3– is the same as losing one H+  Excreting one HCO3– is the same as gaining one H+  Type A intercalated Cells:(a) Exchange of O2 and CO2 in pulmonary capillaries (external respiration)ExhaledInhaledAlveolusInterstitialfluidPulmonarycapillary wallPlasmaRed blood cellReversechlorideshiftCO2CO2CO2CO2 + H2OCO2 + Hb Hb–CO2O2O2O2O2 + Hb–HHb–O2+ H+HCO3–HCO3– + H+H2CO3Cl –Cl –Carbonic anhydrase(b) Exchange of O2 and CO2 in systemic capillaries (internal respiration)Tissue cellInterstitialfluidSystemiccapillary wallPlasmaRed blood cellChlorideshiftCO2CO2CO2CO2 + H2OCO2 + Hb Hb–CO2 + O2O2O2O2O2 + Hb–HHb–O2HCO3–HCO3– + H+H2CO3Cl –Cl –Carbonic anhydraseo Dietary H+ must be balanced by generating new HCO3–o Most filtered HCO3– is used up before filtrate reaches the collecting duct o Intercalated cells actively secrete H+ into urine, which is buffered by phosphates and excretedo Generated “new” HCO3– moves into the interstitial space via a cotransport system and then moves passively into peritubular capillary blood Type B intercalated