Please enable JavaScript.
Coggle requires JavaScript to display documents.
Regulation of acid base balance and pathophysiology (Metabolic reactions…
Regulation of acid base balance and pathophysiology
Metabolic reactions produce an excess of H+
Glycolysis products include H+
Production of ATP produces H+ and CO2
CO2 forms carbonic acid with dissociates quickly -> biggest input of acid under normal conditions
Acid-base balance
Buffer systems
Breathing more/less CO2
Kidney excretion/reabsorption of H+
Buffers
HCO3- in ECF
Proteins, haemoglobin in cells
Phosphates and ammonia in urine
Ventilation
Rapid reflex, takes care of 75% of pH disturbances
Alters the rate and depth of breathing
Limitations
Cannot protect ECF from pH changes due to increased or depressed CO2 levels (cannot buffer itself)
Only functions when respiratory system and control centres are working normally
Limited by availability of bicarbonate ions (needed to bind to H+ to form carbonic acid)
Kidney
Helps maintain bicarbonate reserve via bulk reabsorption of HCO3- in PCT
Phosphate ions and ammonia act as buffers
Causes of acid/base disturbance
If resp acidosis - pCO2 will be high
If metab acidosis - bicarb will be reduced
Uncompensated metabolic alkilosis - pCO2 normal, pH high and bicarb upper end of normal
Compensated metabolic alkalosis - pCO2 elevated, pH high-ish, bicarb very high
Reduced GFR results in kidney dysfunction
Blood changes
Usea & creatinine
Increase K+ and phosphate
Reduced HCO3-
metabolic acidosis
Dilute urine
Causes of reduced GFR
Not always a primary problem with the kidney
Compromised CV system compromises kidney function (as kidneys take up to 20% of CO)
AZOTAEMIA (high levels of nitrogen containing compounds)
Prerenal
Reduced blood supply to kidney
Animal is able to concentrate urine (e.g. to preserve blood volume)
Renal
Intrinsic disease of kidney
Animal is NOT able to concentrate urine
Postrenal
Blockage of urine flow below kidneys
Disturbances of potassium regulation
How occur?
Reduced kidney function - less than normal excretion in an animal that is eating
Animal stops eating - K+ not stored
Disturbances of aldosterone secretion
Acidosis
The homeostasis of pH trumps that of K+
Potassium balance
Hyperkalaemia
Nerve and muscle initially more excitable BUT, depolarised cells cannot repolarise properly and thus become less excitable
Extremely low heart rate
Hypokalaemia
Nerve and muscle cells hyperpolarised (more -ve on inside of cell) and less excitable
Muscle weakness, skeletal, heart