A PII Objectives Exam 4 Power Point 1 Acid Base Balance Objective 1 Explain the effects of H concentration on pH levels in the body pH is the measure of acidity in a solution relative concentration of H in body fluids o Greater H Acidic Lower H Alkaline pH falls when H increases and rises when H decreases All functional proteins are influenced by H so almost all reactions are influenced by the pH of their fluid environment interstitial fluid blood H are by products of metabolism Lactate o Also ketone bodies from ketosis due to a lack of CHO releases H ions into the blood Objective 2 Explain how the 3 major buffering systems work as well as the subsystems of the protein buffering system 3 major buffering systems work to help regulate the H concentration to maintain a neutral pH 1 Chemical Buffers 1st line of defense These act within a fraction of a second in an attempt to resist changes in pH Muscle Carnosine 2 Brain Stem Respiratory Centers Act within 1 3 minutes to counteract acidosis or alkalosis Respiratory Buffer 3 3 Renal Mechanisms Kidneys Require hours or even a day or more to act on changes in blood pH Chemical Buffer Systems o A system of one or more compounds that acts to resist changes in pH when a strong acid or base is added o Compounds bind to H when pH drops and release H when pH rises o A shift in H concentration in one fluid compartment is compensated by a shift in another compartment if 2 or more compounds o Therefore there are 3 Chemical Buffer Systems Bicarbonate Buffer System H2CO3 and NaHCO3 Phosphate Buffer System H2PO4 2 Protein Buffer System Example Hemoglobin and HPO4 o NOTE Chemical buffers can only tie up acids or bases temporarily only kidneys can remove excess from the body 1 1 o Bicarbonate Buffer System The Only important buffer in extracellular fluid ECF Substances H2CO3 Carbonic Acid Weak Acid NaHCO3 Sodium Bicarbonate Salt Weak Base HCL Strong Acid NaOH Sodium Hydroxide Strong Base H2CO3 and NaHCO3 Carbonic Acid and Sodium Bicarbonate Carbonic Weak Acid Salt Weak Base HCL s interaction w Bicarbonate Carbonic Acid weak acid doesn t dissociate completely but HCL does strong acid Bicarbonate weak base which ties up H from HCL o Now pH is only slightly lowered If a strong base is now added sodium hydroxide it causes Carbonic acid to dissociate a little more making H to tie up with OH released by the strong base o Now pH is slightly elevated Buffering Power is related to concentration of substances o Phosphate Buffer System o Protein Buffer System Similar to that of the Bicarbonate Buffer Sodium dihydrogen phosphate NaH2PO4 and monohydrogen phosphate NaHPO4 NaH2PO4 Weak Acid NaHPO4 Weak Base Phosphate concentrations are low in the blood so this is very effective buffer in urine and intracellular fluid ICF of buffering power of all bodily fluids are in the cells and this mostly reflects the buffering capabilities of intracellular proteins Amino Group Carbon Group COOH Organic Acid COOH is a strong acid which releases H when pH rises to counteract it Amino Group NH2 binds w H to become NH3 o This removes H to prevent the solution from becoming too acidic Amphoteric Molecules acid or base depending on the pH of its environment A single protein which can act as an Hemoglobin is charged after releasing O2 H dissociates from Carbonic Acid but H rapidly binds to Hb so pH changes are minimal o Note this rapid binding is because of Hb s charge due to the release of O2 2 2 Respiratory Buffer System o Acts more slowly than the chemical buffers o 2X s the buffering power of all of the chemical buffers combined o As CO2 expelled from lungs Carbonic acid is formed and dissociated in o Hypercapnia H chemoreceptors which Respiratory rate drop in cerebrospinal fluid activates medulla Chemoreceptors will also increase plasma H to counteract o Respiratory Compensations compensate for metabolic acid base alkalosis imbalances o Metabolic acidosis increased respiratory rate and depth o Metabolic alkalosis decreased respiratory rate and depth o CO2 H2O H2CO3 H HCO 3 Renal Buffer System o Only the kidneys can Rid the body of metabolic acids not chemical buffers i e nitrogen Regulate blood levels of alkaline substances and renew chemical buffers that are used up o H is proportional to CO2 in ECF and CO2 is inversely proportional to blood pH HCO3 is lost when CO2 leaves lungs H is retained as HCO3 is secreted which increases H shifting equation to the right Na is reabsorbed from filtrate to maintain balance Need to replenish HCO3 to counteract H retention Objective 3 Explain how the amount of CO2 in the blood affects pH levels Also know what the ventilation response is to high and low CO2 levels in the blood CO2 in the blood dissolves is converted into carbonic acid which breaks into bicarbonate and H Bicarbonate ions are acidic and cause pH levels of the blood to drop H is proportional to CO2 in ECF and CO2 is inversely proportional to blood pH o As CO2 increases pH decreases Bottom line CO2 makes the blood more acidic Objective 4 Explain the ventilation response to pH levels A pH 7 35 causes Respiratory Acidosis o Occurs when someone breathes too shallow or low or hypoventilates o Lungs cannot remove enough CO2 3 3 o CO2 levels get too high causing the pH of the blood to decrease and become too acidic A pH 7 45 causes Respiratory Alkalosis o Occurs when someone breathes very deep or rapidly or o CO2 levels drop too low causing the pH of the blood to rise and Hyperventilates become too alkaline Objective 5 How do acidosis and alkalosis occur Arterial Blood has a pH of 7 4 Venous Blood and Interstitial Fluid have a pH of 7 35 Alkalosis occurs when the Arterial pH rises above 7 45 or becomes too basic Acidosis occurs when the Arterial pH drops below 7 35 or becomes too Intracellular Fluid has a neutral pH of 7 0 acidic Lower pH in the blood demonstrates more acidic metabolites and CO2 Acidosis and alkalosis are categorized by the cause of the condition o Respiratory acidosis or alkalosis results from abnormalities of the respiratory system o Metabolic acidosis or alkalosis results from all causes other than abnormal respiratory functions Objective 6 Determine the levels of bicarbonate with acidosis and alkalosis Metabolic Acidosis Bicarbonate HCO3 22mEq L pH 7 35 Metabolic Alkalosis Bicarbonate HCO3 26mEq L pH 7 45 Power Point 2 Male Reproductive System Objective 1 Explain the parasympathetic and sympathetic innervations of the male reproductive system and the effects of
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