acid base balance Flashcards
what is an acid
proton donator
what is a base
proton acceptor
what is a buffer
- a solution containing substances which can minimise changes in PH
intracellular buffering components examples
- physiochemical include proteins, phosphates
- metabolic
- organeller
- acid extrusion
extracellular buffering components
- physiochemical include hb, albumin, bicarbonate
- metabolic such as changing ventilation rate
what is the normal blood ph
7.35-7.45
what is an volatile acid and example
- carbonic acid dissociates into carbon dioxide and water which can be expelled during expiration as a gas
- volatile acid can be expelled as a gas through the lungs
non volatile acid examples
- all acids other than carbonic acid
- excreted in urine
- usually referred to their anion base e.g. lactate, sulphate
- derived from oxidation of CHO fats and amino acids
what is the buffer of the blood
- H+ + HCO3- > H2CO3 > H20 + CO2
- HCO3- acts as the base and binds with an free H+ ions minimising changes in ph of the blood
- hydrogen ions also buffered by hb and other proteins
what is acidosis and the two types of acidosis
- ph in blood is low so below 7.35
- metabolic acidosis
- respiratory acidosis
what is metabolic acidosis
- low ph
- low levels of base specifically bicarbonate ions
what is the 5 cause of metabolic acidosis
- too much acid ingested e.g. aspirin overdose
- too much acid produced diabetes ketoacidosis, lactate acidosis
- too much base excreted- small bowel fistula
- too little acid excreted- renal failure
- too little base produced- renal failure
what is respiratory acidosis
- low ph
- high partial pressures of carbon dioxide
- hypoventilation
- compensatory to metabolic alkalosis and drugs
- inability to clear co2 due to lung pathology such as copd, pneumonia, muscle weakness
what is the anion gap
- difference between unmeasured anions and cations
- [na+] + [k+]- [hco3-] - [cl-]
- anion gap is 8-16 mol/l usually
- gives indication of cause of metabolic acidosis
what does an increased anion gap suggest
- associate with too much acid being produced/accumulation of acids
- renal failure
- ingestion of acid
- diabetic ketoacidosis (too much acid produced)
- lactic acidosis ( too much acid produced)
what does an normal anion gap suggest
- suggests acidosis might be due to loss of bicarbonate ions or other non- acid causes
- decreased acid excretion
- loss of base (diarrhoea, small bowel fistula)
- normal anion gap associated with hypercholraemia (high chloride levels- can cause hco3 levels to be excreted to compensate increased cl- levels
how does exercise cause acidosis
- tissues undergoing respiration- aerobic
- demand of oxygen exceeds supply so anaerobic respiration takes place
- lactate produce as well as hydrogen ions
- leads to lactate acidosis
how does type 1 diabetes cause acidosis
- no insulin produced
- glucose not utilised as a source or energy
- fats are utilised
- ketone acids form which leads to ketoacidosis
what is alkalosis and the two types
- ph is too high
- metabolic alkalosis
- respiratory alkalosis
what is metabolic alkalosis
- high ph
- high bicarbonate levels
- base excess
what is 3 the causes of metabolic alkalosis
- too much base being produced e.g. compensatory to respiratory acidosis
- too much base ingested e.g. antacids
- too much acid excreted e.g. vomiting
what is respiratory alkalosis
- high ph
- low carbon dioxide levels
- due to hyperventilation which can caused by drugs or compensatory to metabolic acidosis, anxiety
compensatory of metabolic acidosis
- increased ventilation
compensatory of respiratory acidosis
- renal compensation
- causing in a rise in hco3- levels
compensatory of metabolic alkalosis
- decreased ventilation
- hypoventilation
- breath in paper bag
compensatory of respiratory alkalosis
- renal compensation
- increased hco3- excretion
