Urinary acid:base balance

Question 1

What can extreme acidaemia or alkalaemia result in

Answer 1

coma, cardiac failure, circulatory collapse

Question 2

How do buffer systems work?

Answer 2

Act to quickly temporarily bind XS H+ or OH-, sequestering the highly reactive ions until they can be permanently excreted
2. first line of defence, act quickly to moderate changes in pH

Question 3

What are the limitations of respiratory systems for correction of acid-base balances

Answer 3

1. Only functions when respiratory systems and control centres are working normally
2. Limited by availability of bicarbonate ions (bicarbonate reserve)
3. Cannot protect ECF from pH changes due to increased or depressed CO2 levels (cannot buffer itself) - if CO2 is the issue to start with = won’t work
   - responsible for about 75% change tho!

Question 4

By time filtrate has entered DCT what ahs happened to HCO3- and H+

Answer 4

1. HCO3-
   - 100% filtered
   - 100% reabsorbed, 80-90% PCT, 10-20% LoH
2. H+
   - produced in XS by metabolism
   - some unregulated secretion into PCT

Question 5

When does respiratory acidosis occur?

Answer 5

1. issue with respiratory tract
2. CO2 accumualtes because of hypoventilation
3. CO2 builds up = build up of protons in arterial blood = acidemai

Question 6

When does metabolic acidosis occur?

Answer 6

1. Due to either:
   DECREASED BICARBONATE Chronic Diarrhoea, loss of kidney function therefore reduced reabsorption of bicarbonate
2. INCREASED ACID LOAD - diabetic ketoacidosis. producing energy for fats increases ketones = acid into blood

Question 7

Given pH less than 7.35. What could be the cause: how would you investigate

Answer 7

ACIDOSIS

1. Respiratory
   a) read off Pa CO2. if raised = respiratory
   b) only way body can compensate with this is metabolically (kidney)
   c) kidney will compensate by inc bicarbonate level - over time
2. METABOLLIC
   a) look at bicarbonate - if reduced
   b) compensation = respiratory
   c) could be diabetic ketoacidosis, kidney disease, severe faecal loss of bicarbonate during diarrhoea

Question 8

If presented with a patient that has pH greater than 7.45 what could be case- how would you investigate

Answer 8

ALKALOSIS

1. METABOLLIC REASONS
   a) look at bicarbonate conc
   b) if increased = metabollic
   c) compensations = respiratory
2. RESPIRATORY
   a) look at PaCO2
   b) if reduced = lungs are removing CO” at a faster rate than it si being produced
   c) hyperventilation
   d) compensations will be metabollic

Question 9

If animal is persistently vomiting what could this cause

Answer 9

1. alkalosis

2. Vomit = get rid of HCL in stomach = rid of protons