Acids, Bases, PH and Buffers

Acids, Bases, PH and Buffers

1. DEFINE ACID AND BASE

   • Acid - Substance that release Hydrogen ions H+
     • Strong acids completely dissociates
       • Hydrochloric acid -HCl (Stomach)
       • Lactic acid - C3H6O3
     • Weak acids - does not dissociate
       • Carbonic acid -H2CO3
         • Cellular respiration - C02 + H20 > H2C03
       • Amino acid
       • Carboxylic acid - fatty acids
         • methanoic acid
         • ethanoic acid
       • Ascorbic acid - Vitamin C
   • Base - Substance that take up H+, Proton acceptors, aka alkali
     • Strong base - Completely dissociates
       • NaOH > NA + OH- Sodium hydroxide
     • Weak acid - does not dissociate
       • Magnesium Hydroxide - antacid
       • Aqueous ammonia - urine Amino group in proteins

2. Ionize

   • To dissociate into electrically charged species - H20 > H+ (acid) + OH- (base)

3. PH SCALE

   • Proportion of Hydrogens
   • 0-14
   • More H+, PH goes down 6-1
   • OH-, PH goes up 8
   • PH = 7.35-7.45 BLOOD - NEEDS to be in this range

4. ACIDOSIS - PH Below -7.35, INCREASED h+ concentration

   • Respiratory Acidosis
     • Higher CO2 > Higher H2Co3 > Higher H+
       • Hypoventilation due to asthma, COPD, oedma
       • Symptoms - Shortness of breath, arrhythmia, increased heart rate, Headaches
     • Respiratory acidosis is when the lungs cannot remove all of the carbon dioxide the body produces. This causes body fluids, especially the blood, to become too acidic
     • Lactoacidosis, anaerobic glycoysis
   • Metabolic Acidosis
     • Metabolic acidosis is increased acid produced or ingested by the body, the decreased renal excretion of acid, or bicarbonate loss from the body.
     • Symptoms - Confusion, drowsiness, decreased BP, Kussmal respiration
     • Causes by
       • Diarrohea - LOss of Bicorbonate ions
       • fasting/starving - DIABETIES
         • Diabetic ketoacidosis
           • No insuline to move glucose, uses fat = creates keatones
       • Kidney failure
         • do not excrete H+ in urine
       • Lactoacidosis- shock
       • Low HC03-
   • Blood test results
     • Normal range PH 7.35-7.45 PACO2 4.7-6.0. kPA HC0-3 -19-29mmol/l
       • Respiratory
         • If the PH is point in the opposite direction to the PaCo2 and HC0-3
       • Metabolic
         • If all 3 values are pointing in the same direction e.g low ph, low PaCo2, low HC03- or High, high, high
     • At Altitude Ph will rise, PCo2 will fall

5. ALKALOSIS - PH Above 7.45 decrease h+ concentration

   • Respiratory Alkalosis
     • Hyperventilation
       • Rise in PH, decrease Pco2, decrease H+
       • Light headedness, hypokalemia, numbness
   • Metabolic Alkalosis
     • Caused by vomiting - getting ride of H+ (hydrochloric acid), Diuretics increases urine output. alkaline drug, dehydration
       • Increase HC03- (bicarbonate)
       • Confusion, tremors, muscle cramps, restlessness

6. Buffers

   • acid-balance regulation - resist ph change, can be acid or base Buffers are compounds which maintain constant PH when an acid or alkais are added
   • Carbonic acid/bicarbonate - ECF buffer
     • c02 + h20 <> H2Co3 <> H+ hC03- <> H+ cO3-2
       • Acts as both a acid and base - system fails with respiratory system problems
   • Phosphate Buffer system
     • ICF - H+ release Urine
       • H2P04- and HPo42-
   • Haemoglobin
     • Transports Co2
       • Buffers Co2 - CO2 + H20 + H2C03