Block 1: Acid-Base Imbalances Flashcards
Why is pH homeostasis important?
It maintains normal body function.
What is an acid?
A substance that can donate a Hydrogen (H+) ion.
What is a base?
A substance that can gain or accept a Hydrogen (H+) ion.
What is the normal pH of blood?
7.35-7.45 is normal
What acids are produced by the body during metabolism?
i) Carbonic acid from CO2 - aerobic respiration
ii) Lactic acid - from anaerobic respiration.
iii) Ketones - lipid metabolism
iv) Sulphuric acid - oxidation of sulphur containing amino acids
v) Phosphoric acids - from breakdown of phosphoproteins and ribonucleotides.
How is pH homeostasis regulated?
Buffers
What are important buffer systems to maintain pH?
- Bicarbonate/Carbonic acid buffer
- Proteins
- Haemoglobin
- Phophate buffer system
What does bicarbonate do with regards to buffering?
Accepts hydrogen ions
What does carbonic acid do with regards to buffering?
Donates hydrogen ions
What are buffers?
Helps maintain consistency - buffers against change
How do the lungs compensate in changes to pH?
By altering ventilation rate; They increase and decrease the CO2 levels and therefore the amount of carbonic acid in the blood.
How do the kidneys help to maintain homeostasis?
By excreting or retaining bicarbonate (base) AND By excreting or retaining hydrogen ions (acids).
Which is the faster response to pH homeostasis - lungs or kidneys?
Lungs
Define acidosis?
pH below 7.35
What conditions could cause metabolic acidosis?
i) Lactoacidosis
ii) Ketoacidosis
iii) Renal failure
iv) Prolonged vomiting or diarrhoea
How does Respiratory acidosis occur?
Impaired lung function which can produce a build-up of carbonic acid from the body’s inability to excrete CO2.
Define alkalosis?
pH greater than 7.45
How is respiratory alkalosis caused?
Excessive loss of CO2 - Hyperventilation
What are some clinical cause of metabolic alkalosis?
i) vomiting, loss of gastric juices
ii) Diuretics
iii) Overdose of antacids
What blood gas tests can be done?
i) pH
ii) PCO2 (carbon dioxide)
iii) HCO3 (bicarbonate)
iv) PO2 (oxygen)
v) O2% Saturation
What are 3 things that blood values determine?
i) If a person is acidosis or alkalosis
ii) If it is metabolic or respiratory
iii) If condition is compensated or decompensated
What is used to treat metabolic acidosis?
Bicarbonate is given
What is used to treat metabolic alkalosis?
Chloride containing solution is given
What type of acid/base disorder is likely to develop in someone with chronic breathing problems?
Respiratory acidosis
What are the pH cutoffs for acid-base before cell death occurs?
pH 6.8-7.7
Why is lactic acid produced?
When tissue is not supplied with enough oxygen
When are ketones produced?
When there is high fat metabolism by tissues and not enough glucose.
What 3 mechanisms are involved to maintain homeostasis?
Lungs, kidneys and buffers.
