Physiology of Kidney Acid Base Balance Flashcards
What is the normal pH of arterial blood?
7.4
Protons can be bound to protein or acid, however, in order to contribute to pH, what must proton ions be?
Free
What are some of the sources of protons (H+) in the body?
Respiratory acid
Metabolic acid
What is a respiratory acid?
Carbonic acid is formed from carbon dioxide dissolving in water
What does carbonic acid dissociate into?
Carbonates and protons
Why is increased carbon dioxide production in exercise normally not a problem for the body?
It’s compensated for by increased ventilation
What happens if there is impaired lung function in someone who is exercising?
Carbon dioxide builds up as the body cannot fully release and exhale the carbon dioxide, leading to increased respiratory acid production
Metabolic acids are produced via metabolism. What are the two types of metabolic acid?
Inorganic acids
Organic acids
Give an example of an inorganic metabolic acid.
Sulphuric and phosphoric acid due to sulphur/phosphate containing amino acids
Give an example of an organic metabolic acid.
Fatty acids, lactic acid
What is the major source of alkaline in the body?
Oxidation of organic anion such as citrate
Buffers?
Solutions which minimise changes in pH when proton ions are added or removed
What is the most important extracellular buffer?
Bicarbonate buffer
What is the normal pCO2?
40mmHg or 5.3kPa
Protons do not get removed from the body, so how does it work so that these protons don’t contribute to pH thanks to buffers?
Bicarbonate buffers the protons and the respiratory compensation greatly increases the buffering capacity so that free protons ions are prevented from contributing to pH
->basically, just understand that protons are not removed, just buffered so they can’t contribute to pH
What are the two factors which are important when protecting the pH?
Bicarbonate
Carbon dioxide
How is carbon dioxide regulated?
Respiration
How is bicarbonate regulated?
Directly by the kidney
If there is a disruption to the regulation of the bicarbonate, how is this compensated for?
Compensated by ventilation
List some of the primary intracellular buffers.
Proteins, organic and inorganic phosphates
Haemoglobin in erythrocytes
What can buffering of proton ions by ICF buffers cause changes to?
Can cause changes in plasma electrolytes
What is done as compensation when transporting protons into cells to be buffered intracellularly?
Needs to be co-transport of chloride in red cells or potassium
In acidosis, there is movement of potassium out of the cells. What can this cause?
Hyperkalaemia, leading to depolarisation of excitable tissues, ventricular fibrillation and death
What else provides an additional store for buffer?
Bone carbonate
->very important in chronic acid loads in renal failure as can lead to wasting of bones