Karteikarten
Acid base physiology
Karten in diesem Stapel (24)
- 1pH is the negative logarithm to the base 10 of hydrogen ion concentration, what is the formula?pH= -log10[H+]
- 2A ph 7.35 - 7.45 corresponds to an H+ concentration of what?34 - 46nmol/L
- 3Stable body pH is important for a number of essential functions, why, what is affected?Enzymes need a specific pH to perform their reactions
Membrane excitability and energy are affected with deranged pH
pH influences the state of ionisation of molecules in body (intra/extra cellular)
Nervous and endocrine systems suffer with abnormal pH - 4What is the relationship between pH and H+, what increases/ decreases?Relationship between H+ and pH concentration is inverse, as pH decreases, H+ concentration increases
- 5At a pH of 7.3, what is the concentration of H+?50nmol/L
- 6At a pH of 6.8, what is the H+ concentration?158nmol/L
- 7What is a hydrogen ion?A hydrogen ion is a molecule without its electron, which makes it a proton
- 8What is an acid?An acid is a substance that donates a proton, (H+ donor) eg, HA
- 9What is a base?A substance that accepts a proton (H+ recipient) eg, A-
- 10What is the Henderson- Hasselbach equation?Describes the relationship between pH, the dissociation constant and the concentration of a weak acid and its base salt
pH = pKa + log [-A]/[HA] - 11How does the body maintain the pH within its normal range?Buffering
Compensation
correction - 12What is a buffer?A buffer is a substance that resists change in pH by absorbing or releasing hydrogen ions
- 13What buffer systems are there?Carbonic acid bicarbonate buffer system
Haemoglobin
Plasma proteins
Phosphate buffer system - 14The relationship of HCO3, PaCO2 and pH can be represented by what equation (siggaard Anderson approach)?pH= 6.1 + log = HCO3
0.03 x PaCO2 (mmHg) - 15What is carbonic anhydrase?Enzyme that catalyses the reaction of carbon dioxide and water to form carbonic acid.
CO2 + H20 <> H+ +HCO3 - 16Where is carbonic anhydrase present?Large amounts in red blood cells
renal tubules
lung alveolar cells, buffers
CO2 and O2 transport
gastric mucosa- hydrochloric acid production
Ciliary body - aqueous humour production - 17How does renal compensation occur and how long does it take?Controls plasma bicarbonate by altering the renal secretion of H+ an the production and reabsorption of bicarbonate
Takes hours to days. - 18What is the anion gap?The difference between the measured cation and anions concentration in plasma
Used in differential diagnosis of metabolic acidosis. - 19How do you measure the anion gap?Anion gap = [K+] + [Na+] - [Cl-] - [HCO3-]
- 20What is the normal anion gap?8 - 16 mmol/L
- 21What unmeasured anions does the anion gap measure?Phosphate, sulphate, acetate and ketones
- 22What may be the cause of a raised anion gap metabolic acidosis?lactic acidosis
ketoacidosis
AKI/CKD
Toxic alcohols
salicylate poisoning - 23What may be the cause of a normal anion gap metabolic acidosis?Diarrhoea
hyperchloraemia - IV n/saline
bicarbonate loss
renal tubular acidosis - 24What is base excess?The amount of acid or base required to restore a litre of blood back to a normal pH at PCO2 5.3 Kpa and at a temperature of 37
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- Karteikarten am Acid base physiology, erstellt von Laura Foster am 02/07/2017.
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