Acid -- base homeostasis - wikipedia Acid -- base homeostasis Acids and bases pH Reaction Titration Extraction Dissociation constant ( acid ) Acid strength Acidity function Buffer solutions Proton affinity Self - ionization of water Amphoterism Acid types Brønsted Lewis Mineral Organic Strong Superacids Weak Monobasic acid Dibasic acid Tribasic acid Solid Base types Brønsted Lewis Organic Strong Superbases Non-nucleophilic Weak Acid -- base homeostasis is the homeostatic regulation of the pH of the body 's extracellular fluid ( ECF ). The proper balance between the acids and bases in the ECF is crucial for the normal physiology of the body, and cellular metabolism. The pH of the intracellular fluid and the extracellular fluid need to be maintained at a constant level. Many extracellular proteins such as the plasma proteins and membrane proteins of the body 's cells are very sensitive for their three dimensional configurations to the extracellular pH. Stringent mechanisms therefore exist to maintain the pH within very narrow limits. Outside the acceptable range of pH, proteins are denatured ( i.e. their 3 - D structure is deranged ), causing enzymes and ion channels ( among others ) to malfunction. In humans and many other animals, acid -- base homeostasis is maintained by multiple mechanisms involved in three lines of defence. The first line of defence are the various chemical buffers which minimize pH changes that would otherwise occur in their absence. They do not correct pH deviations, but only serve to reduce the extent of the change that would otherwise occur. These buffers include the bicarbonate buffer system, the phosphate buffer system, and the protein buffer system. Physiological corrective measures make up of the second and third lines of defence. This is because they operate by making changes to the buffers, each of which consists of two components : a weak acid and an weak base. It is the ratio of weak acid to weak base that determines the pH of the solution. Thus, by manipulating firstly the concentration of the weak acid, and secondly the weak base, the pH of the extracellular fluid ( ECF ) can be adjusted very accurately to the correct value. The bicarbonate buffer, consisting of a mixture of carbonic acid ( H CO ) and a bicarbonate ( HCO − 3 ) salt in solution, is the most abundant buffer in the extracellular fluid, and it is also the buffer whose acid to base ratio can be changed very easily and rapidly. Thus the second line of defence of the pH of the ECF consists of controlling of the carbonic acid concentration in the ECF. This is achieved by changes in the rate and depth of breathing ( i.e. by hyperventilation or hypoventilation ), which blows off or retains carbon dioxide ( and thus carbonic acid ) in the blood plasma. The third line of defence is the renal system, which can add or remove bicarbonate ions to or from the ECF. The bicarbonate is derived from metabolic carbon dioxide which is enzymatically converted to carbonic acid in the renal tubular cells. The carbonic acid spontaneously dissociates into hydrogen ions and bicarbonate ions. When the pH in the ECF tends to fall ( i.e. become more acid ) the hydrogen ions are excreted into the urine, while the bicarbonate ions are secreted into the blood plasma, causing the plasma pH to rise ( correcting the initial fall ). The converse happens if the pH in the ECF tends to rise : the bicarbonate ions are then excerted into the urine and the hydrogen ions into the blood plasma. An acid -- base imbalance is known as acidemia when the acidity is high, or alkalemia when the acidity is low. Contents 1 Acid -- base balance 2 Imbalance 3 See also 4 References 5 External links Acid -- base balance The pH of the extracellular fluid, including the blood plasma, is normally tightly regulated between 7.36 and 7.42, by the chemical buffer s, the respiratory system, and the renal system. Aqueous buffer solutions will react with strong acids or strong bases by absorbing excess hydrogen H + ions, or hydroxide OH − ions, replacing the strong acids and bases with weak acids and weak bases. This has the effect of damping the effect of pH changes, or reducing the pH change that would otherwise have occurred. But buffers can not correct abnormal pH levels in a solution, be that solution in a test tube or in the extracellular fluid. Buffers typically consist of a pair of compounds in solution, one of which is a weak acid and the other a weak base. The most abundant buffer in the ECF consists of a solution of carbonic acid ( H CO ), and the bicarbonate ( HCO − 3 ) salt of, usually, sodium ( Na ). Thus, when there is an excess of OH − ions in the solution carbonic acid partially neutralizes them by forming H O and bicarbonate ( HCO − 3 ) ions. An excess of H ions is partially neutralized by the bicarbonate component of the buffer solution to form carbonic acid ( H CO ), which, because it is a weak acid, remains largely in the undissociated form, releasing very much fewer H ions into the solution than the original strong acid would have done. The pH of a buffer solution depends solely on the ratio of the molar concentrations of the weak acid to the weak base. The higher the concentration of the weak acid in the solution ( compared to the weak base ) the lower the resulting pH of the solution. Similarly, if the weak base predominates the higher the resulting pH. This principle is exploited to regulate the pH of the extracellular fluids ( rather than just buffering the pH ). For the carbonic acid - bicarbonate buffer, a molar ratio of weak acid to weak base of 1 : 20 produces a pH of 7.4 ; and vice versa - when the pH of the extracellular fluids is 7.4 then the ratio of carbonic acid to bicarbonate ions in that fluid is 1 : 20. This relationship is described mathematically by the Henderson -- Hasselbalch equation, which, when applied to the carbonic acid - bicarbonate buffer system in the extracellular fluids, states that : p H = p K a H 2 C O 3 + log 10 ⁡ ( ( H C O 3 − ) ( H 2 C O 3 ) ), ( displaystyle mathrm ( pH ) = mathrm ( p ) K_ ( mathrm ( a ) ~ mathrm ( H ) _ ( 2 ) mathrm ( CO ) _ ( 3 ) ) + log _ ( 10 ) left ( ( \frac ( ( mathrm ( HCO ) _ ( 3 ) ^ ( - ) ) ) ( ( mathrm ( H ) _ ( 2 ) mathrm ( CO ) _ ( 3 ) ) ) ) \right ), ) where : pH is the acidity in the plasma pK is the cologarithm of the acid dissociation constant of carbonic acid. It is equal to 6.1. ( HCO − 3 ) is the molar concentration of bicarbonate in the blood plasma ( H CO ) is the molar concentration of carbonic acid in the blood plasma However, since the carbonic acid concentration is directly proportional to the partial pressure of carbon dioxide ( P C O 2 ( displaystyle P_ ( ( mathrm ( CO ) ) _ ( 2 ) ) ) ) in the extracellular fluid, the equation can be rewritten as follows : p H = 6.1 + log 10 ⁡ ( ( H C O 3 − ) 0.0307 × P C O 2 ), ( displaystyle mathrm ( pH ) = 6.1 + log _ ( 10 ) left ( ( \frac ( ( mathrm ( HCO ) _ ( 3 ) ^ ( - ) ) ) ( 0.0307 \times P_ ( mathrm ( CO ) _ ( 2 ) ) ) ) \right ), ) where : pH is the acidity in the plasma ( HCO − 3 ) is the molar concentration of bicarbonate in the plasma P is the partial pressure of carbon dioxide in the blood plasma. The pH of the extracellular fluids can thus be controlled by separately regulating the partial pressure of carbon dioxide ( which determines the carbonic acid concentration ) and bicarbonate ion concentration in the extracellular fluids. There are therefore at least two homeostatic negative feedback systems responsible for the regulation of the plasma pH. The first is the homeostatic control of the blood partial pressures of oxygen and carbon dioxide, which determines the carbonic acid concentration in the plasma, and can change the pH of the arterial plasma within a few seconds. The partial pressure of carbon dioxide in the arterial blood is monitored by the central chemoreceptors of the medulla oblongata, and so are part of the central nervous system. These chemoreceptors are sensitive to the pH and levels of carbon dioxide in the cerebrospinal fluid. ( The peripheral chemoreceptors are located in the aortic bodies and carotid bodies adjacent to the arch of the aorta and to the bifurcation of the carotid arteries. These chemoreceptors are sensitive to changes in the partial pressure of oxygen in the arterial blood and are not directly involved with pH homeostasis. ) The central chemoreceptors send their information to the respiratory centres in the medulla and pons of the brainstem. The respiratory centers then determine the average rate of ventilation of the alveoli of the lungs, to keep the partial pressure carbon dioxide in the arterial blood constant. The respiratory center does so via motor neurons which activate the muscles of respiration ( in particular the diaphragm ). A rise in the partial pressure of carbon dioxide in the arterial blood plasma above 5.3 kPa ( 40 mmHg ) reflexly causes an increase in the rate and depth of breathing. Normal breathing is resumed when the partial pressure of carbon dioxide has returned to 5.3 kPa. The converse happens if the partial pressure of carbon dioxide falls below the normal range. Breathing may be temporally halted, or slowed down to allow carbon dioxide to accumulate once more in the lungs and arterial blood. The sensor for the plasma HCO − 3 concentration is not known for certain. It is very probable that the renal tubular cells of the distal convoluted tubules are themselves sensitive to the pH of the plasma. The metabolism of these cells produces CO, which is rapidly converted to H and HCO − 3 through the action of carbonic anhydrase. When the extracellular fluids tend towards acidity, the renal tubular cells secrete the H ions into the tubular fluid from where they exit the body via the urine. The HCO − 3 ions are simultaneously secreted into the blood plasma, thus raising the bicarbonate ion concentration in the plasma, lowering the carbonic acid / bicarbonate ion ratio, and consequently raising the pH of the plasma. The converse happens when the plasma pH rises above normal : bicarbonate ions are excreted into the urine, and hydrogen ions into the plasma. These combine with the bicarbonate ions in the plasma to form carbonic acid, thus raising the carbonic acid : bicarbonate ratio in the extracellular fluids, and returning its pH to normal. In general metabolism produces more waste acids than bases. The urine is therefore generally acid. This urinary acidity is, to a certain extent, neutralized by the ammonia ( NH ) which is excreted into the urine when glutamate and glutamine ( carriers of excess, no longer needed, amino groups ) are deaminated by the distal renal tubular epithelial cells. Thus some of the `` acid content '' of the urine resides in the resulting ammonium ion ( NH ) content of the urine, though this has no effect on pH homeostasis of the extracellular fluids. Imbalance An acid base nomogram for human plasma, showing the effects on the plasma pH when carbonic acid ( partial pressure of carbondioxide ) or bicarbonate occur in excess or are deficient in the plasma Acid -- base imbalance occurs when a significant insult causes the blood pH to shift out of the normal range ( 7.35 to 7.45 ). In the fetus, the normal range differs based on which umbilical vessel is sampled ( umbilical vein pH is normally 7.25 to 7.45 ; umbilical artery pH is normally 7.18 to 7.38 ). An excess of acid in the blood is called acidemia and an excess of base is called alkalemia. The imbalance is classified based on the cause of the disturbance ( respiratory or metabolic ) and the direction of change in pH ( acidosis or alkalosis ). There are four basic processes : metabolic acidosis, respiratory acidosis, metabolic alkalosis, and respiratory alkalosis. One or a combination may occur at any given time. For instance, a metabolic acidosis ( as in uncontrolled diabetes mellitus ) is almost always partially compensated for by a respiratory alkalosis ( hyperventilation ), or a respiratory acidosis can be completely or partially corrected by a metabolic alkalosis. See also Acid ash hypothesis References ^ Jump up to : Hamm, LL ; Nakhoul, N ; Hering - Smith, KS ( 7 December 2015 ). `` Acid - Base Homeostasis. ''. Clinical journal of the American Society of Nephrology : CJASN. 10 ( 12 ) : 2232 -- 42. PMID 26597304. doi : 10.2215 / CJN. 07400715. Jump up ^ J., Tortora, Gerard ( 2012 ). Principles of anatomy & physiology. Derrickson, Bryan. ( 13th ed. ed. ). Hoboken, NJ : Wiley. pp. 42 -- 43. ISBN 9780470646083. OCLC 698163931. CS1 maint : Extra text ( link ) Jump up ^ Macefield, Gary ; Burke, David ( 1991 ). `` Paraesthesiae and tetany induced by voluntary hyperventilation : increased excitability of cutaneous and motor axons ''. Brain. 114 ( 1 ) : 527 -- 540. doi : 10.1093 / brain / 114.1. 527. Jump up ^ Stryer, Lubert ( 1995 ). Biochemistry. ( Fourth ed. ). New York : W.H. Freeman and Company. p. 347, 348. ISBN 0 7167 2009 4. Jump up ^ Adrogué, H.E. ; Adrogué, H.J. ( April 2001 ). `` Acid - base physiology ''. Respiratory Care. 46 ( 4 ) : 328 -- 341. ISSN 0020 - 1324. PMID 11345941. ^ Jump up to : Tortora, Gerard J. ; Anagnostakos, Nicholas P. ( 1987 ). Principles of anatomy and physiology ( Fifth ed. ). New York : Harper & Row, Publishers. pp. 698 -- 700. ISBN 0 - 06 - 350729 - 3. ^ Jump up to : Bray, John J. ( 1999 ). Lecture notes on human physiology. Malden, Mass. : Blackwell Science. p. 556. ISBN 978 - 0 - 86542 - 775 - 4. ^ Jump up to : Garrett, Reginald H. ; Grisham, Charles M ( 2010 ). Biochemistry. Cengage Learning. p. 43. ISBN 978 - 0 - 495 - 10935 - 8. ^ Jump up to : MedlinePlus Encyclopedia Metabolic acidosis ^ Jump up to : Tortora, Gerard J. ; Anagnostakos, Nicholas P. ( 1987 ). Principles of anatomy and physiology ( Fifth ed. ). New York : Harper & Row, Publishers. pp. 581 -- 582, 675 -- 676. ISBN 0 - 06 - 350729 - 3. ^ Jump up to : Stryer, Lubert ( 1995 ). Biochemistry. ( Fourth ed. ). New York : W.H. Freeman and Company. pp. 39, 164, 630 -- 631, 716 -- 717. ISBN 0 7167 2009 4. ^ Jump up to : Tortora, Gerard J. ; Anagnostakos, Nicholas P. ( 1987 ). Principles of anatomy and physiology ( Fifth ed. ). New York : Harper & Row, Publishers. pp. 494, 556 -- 582. ISBN 0 - 06 - 350729 - 3. Jump up ^ MedlinePlus Encyclopedia Blood gases Jump up ^ Caroline, Nancy ( 2013 ). Nancy Caroline 's Emergency care in the streets ( 7th ed. ). Buffer systems : Jones & Bartlett Learning. pp. 347 -- 349. ISBN 978 - 1449645861. Jump up ^ Hamm, L. Lee ; Nakhoul, Nazih ; Hering - Smith, Kathleen S. ( 2015 - 12 - 07 ). `` Acid - Base Homeostasis ''. Clinical journal of the American Society of Nephrology : CJASN. 10 ( 12 ) : 2232 -- 2242. ISSN 1555 - 905X. PMC 4670772. PMID 26597304. doi : 10.2215 / CJN. 07400715. ^ Jump up to : J., Tortora, Gerard ( 2010 ). Principles of anatomy and physiology. Derrickson, Bryan. ( 12th ed ed. ). Hoboken, NJ : John Wiley & Sons. p. 907. ISBN 9780470233474. OCLC 192027371. CS1 maint : Extra text ( link ) Jump up ^ Levitzky, Michael G. ( 2013 ). Pulmonary physiology ( Eighth ed. ). New York : McGraw - Hill Medical. p. Chapter 9. Control of Breathing. ISBN 978 - 0 - 07 - 179313 - 1. Jump up ^ Rose, Burton ; Helmut Rennke ( 1994 ). Renal Pathophysiology. Baltimore : Williams & Wilkins. ISBN 0 - 683 - 07354 - 0. Jump up ^ Yeomans, ER ; Hauth, JC ; Gilstrap, LC III ; Strickland DM ( 1985 ). `` Umbilical cord pH, PCO2, and bicarbonate following uncomplicated term vaginal deliveries ( 146 infants ) ''. Am J Obstet Gynecol. 151 : 798 -- 800. PMID 3919587. doi : 10.1016 / 0002 - 9378 ( 85 ) 90523 - x. External links Stewart 's original text at acidbase.org On - line text at AnaesthesiaMCQ.com Overview at kumc.edu Tutorial at acid-base.com Online acid -- base physiology text Diagnoses at lakesidepress.com Interpretation at nda.ox.ac.uk Acids and Bases - definitions Cardiopulmonary therapy Diagnostic Pulmonary function testing Polysomnography Disease Asthma Bronchiectasis COPD Cystic fibrosis Tuberculosis Pneumonia Therapy Hyperinflation therapy Pulmonary hygiene Mechanical ventilation Oxygen therapy See also Health care Electrolyte imbalance and acid -- base imbalance ( E86 -- E87, 276 ) Volume status Volume contraction ( dehydration / hypovolemia ) Hypervolemia Electrolyte Sodium High Hypernatremia Salt poisoning Low Hypotonic Isotonic Potassium High Low Chloride High Low Calcium High Low Acid -- base Acidosis Metabolic : High anion gap Ketoacidosis Diabetic ketoacidosis Lactic Normal anion gap Hyperchloremic Renal tubular Respiratory Alkalosis Metabolic Contraction alkalosis Respiratory Both Mixed disorder of acid - base balance Physiology of the kidneys and acid - base physiology Renal function Secretion clearance Pharmacokinetics Clearance of medications Urine flow rate Reabsorption Solvent drag sodium chloride urea glucose oligopeptides protein Renal function Glomerular filtration rate Creatinine clearance Renal clearance ratio Urea reduction ratio Kt / V Standardized Kt / V Measures of dialysis Hemodialysis product PAH clearance ( Effective renal plasma flow Extraction ratio ) Filtration Renal blood flow Ultrafiltration Countercurrent exchange Filtration fraction Hormones Antidiuretic hormone Aldosterone Atrial natriuretic peptide Renin Erythropoietin Calcitriol Prostaglandins Acid - base balance Fluid balance Darrow Yannet diagram Body water : Intracellular fluid / Cytosol Extracellular fluid ( Interstitial fluid Plasma Transcellular fluid ) Base excess Davenport diagram Anion gap Arterial blood gas Winter 's formula Buffering Bicarbonate buffer system Respiratory compensation Renal compensation Other Fractional sodium excretion BUN - to - creatinine ratio Tubuloglomerular feedback Natriuresis Urine Human homeostasis Blood composition Blood sugar Osmoregulation Pressure : Renin -- angiotensin system Acid -- base Fluid balance Hemostasis Other Predictive Thermoregulation Retrieved from `` https://en.wikipedia.org/w/index.php?title=Acid -- base_homeostasis&oldid = 805018426 '' Categories : Human homeostasis Acid -- base physiology Acid -- base disturbances Equilibrium chemistry Respiratory therapy Hidden categories : CS1 maint : Extra text Talk Contents About Wikipedia Bosanski Català Čeština Deutsch Ελληνικά Español فارسی Français Հայերեն Italiano Polski Português Română Русский Slovenčina Српски / srpski Suomi Svenska Türkçe Українська Edit links This page was last edited on 12 October 2017, at 15 : 13. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: what two body systems are involved with ph balance
Answer: respiratory