Block 1: Acid-Base Imbalances

Question 1

Why is pH homeostasis important?

Answer 1

It maintains normal body function.

Question 2

What is an acid?

Answer 2

A substance that can donate a Hydrogen (H+) ion.

Question 3

What is a base?

Answer 3

A substance that can gain or accept a Hydrogen (H+) ion.

Question 4

What is the normal pH of blood?

Answer 4

7.35-7.45 is normal

Question 5

What acids are produced by the body during metabolism?

Answer 5

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.

Question 6

How is pH homeostasis regulated?

Answer 6

Buffers

Question 7

What are important buffer systems to maintain pH?

Answer 7

• Bicarbonate/Carbonic acid buffer
• Proteins
• Haemoglobin
• Phophate buffer system

Question 8

What does bicarbonate do with regards to buffering?

Answer 8

Accepts hydrogen ions

Question 9

What does carbonic acid do with regards to buffering?

Answer 9

Donates hydrogen ions

Question 10

What are buffers?

Answer 10

Helps maintain consistency - buffers against change

Question 11

How do the lungs compensate in changes to pH?

Answer 11

By altering ventilation rate; They increase and decrease the CO2 levels and therefore the amount of carbonic acid in the blood.

Question 12

How do the kidneys help to maintain homeostasis?

Answer 12

By excreting or retaining bicarbonate (base) AND By excreting or retaining hydrogen ions (acids).

Question 13

Which is the faster response to pH homeostasis - lungs or kidneys?

Answer 13

Lungs

Question 14

Define acidosis?

Answer 14

pH below 7.35

Question 15

What conditions could cause metabolic acidosis?

Answer 15

i) Lactoacidosis
ii) Ketoacidosis
iii) Renal failure
iv) Prolonged vomiting or diarrhoea

Question 16

How does Respiratory acidosis occur?

Answer 16

Impaired lung function which can produce a build-up of carbonic acid from the body’s inability to excrete CO2.

Question 17

Define alkalosis?

Answer 17

pH greater than 7.45

Question 18

How is respiratory alkalosis caused?

Answer 18

Excessive loss of CO2 - Hyperventilation

Question 19

What are some clinical cause of metabolic alkalosis?

Answer 19

i) vomiting, loss of gastric juices
ii) Diuretics
iii) Overdose of antacids

Question 20

What blood gas tests can be done?

Answer 20

i) pH
ii) PCO2 (carbon dioxide)
iii) HCO3 (bicarbonate)
iv) PO2 (oxygen)
v) O2% Saturation

Question 21

What are 3 things that blood values determine?

Answer 21

i) If a person is acidosis or alkalosis
ii) If it is metabolic or respiratory
iii) If condition is compensated or decompensated

Question 22

What is used to treat metabolic acidosis?

Answer 22

Bicarbonate is given

Question 23

What is used to treat metabolic alkalosis?

Answer 23

Chloride containing solution is given

Question 24

What type of acid/base disorder is likely to develop in someone with chronic breathing problems?

Answer 24

Respiratory acidosis

Question 25

What are the pH cutoffs for acid-base before cell death occurs?

Answer 25

pH 6.8-7.7

Question 26

Why is lactic acid produced?

Answer 26

When tissue is not supplied with enough oxygen

Question 27

When are ketones produced?

Answer 27

When there is high fat metabolism by tissues and not enough glucose.

Question 28

What 3 mechanisms are involved to maintain homeostasis?

Answer 28

Lungs, kidneys and buffers.