Acid-base Imbalances Flashcards
What is an acid?
A substance that releases H+
What is a base?
A substance takes up H+
What two types of acids are continuously being made and how are they excreted?
- carbonic acid —> excreted through lungs
- metabolic acid —> excreted by the kidneys
What is buffering?
Process of body fluids resisting large changes in pH when acids or bases are added or removed
What are buffers?
Pairs of weak acids and its base
For the ECF, what is the most important buffering system?
Bicarbonate buffering system
What does the bicarbonate buffering system consist of and what is the ratio?
-20 bicarbonate: 1 carbonic acid
How quickly does the respiratory buffer work?
Minutes
What does free H+ form in the pulmonary capillaries? What does it turn into in the lungs? How is that blown off? What does this do to the blood pH?
- it forms carbonic acid
- it turns into H2O and CO2
- it is blown off by breathing
- blood becomes less acidic and increases pH
How quickly does the renal buffer system work?
24 hours initially then possible days for effective action
What do the kidney reabsorb/conserve in the renal buffer system? What do they eliminate? What does this do to blood pH?
- they conserve bicarbonate
- they eliminate H+ (excretion of acidic urine)
- blood less acidic, increase pH
How does acidosis occur?
- buffers overwhelmed and body fluids have too much acid
- acid excretion not able to keep up with acid production or intake
How does alkalosis occur?
- too little acid, buffers unable to keep pH in normal range
- occurs when there is too much bicarbonate added to the system and acid excretion > production
What are the general risk factors of acid-base imbalances?
- excessive production or intake of metabolic acid
- altered acid buffering due to a loss or gain of HCO3
- altered acid excretion
- abnormal shift of H+ into the cells
Examples of excessive production or intake of metabolic acid
DKA, poisoning
Examples of altered acid buffering due to a loss or gain of HCO3
Loss: Diarrhea
Gain: overuse of antacid or Na+ bicarbonate therapy
Examples of altered acid excretion
- renal failure
- ppl with respiratory issues (COPD, atelectasis, PNA)
- elderly-kidneys do not work as well
What causes an abnormal shift of H+ into cells?
Hypokalemia- K+ ions leave cells and H+ enters cell to maintain electrochemical charge