The role of ventilation in acid/base balance

Question 1

What does the function of proteins depend on and how is this achieved?

Answer 1

→ Depends on a specific secondary, tertiary and quaternary structure
→ Achieved by intra and inter chain bonding

Question 2

What can denature proteins?

Answer 2

→ Temperature, pH, pressure can denature proteins

Question 3

How is arterial pH tightly regulated?

Answer 3

→ Presence of buffering systems and regulating the level of molecules associated with acid/base production

Question 4

What is a buffer?

Answer 4

→ Weak acid + conjugate base

Question 5

How do buffers work when H+ is added?

Answer 5

→ When there are excess H+ ions present they are mopped up by reacting with the conjugate base to form the weak acid
→ H+ + HCO3- ⇌ H2CO3
→ The end product is much less acidic

Question 6

How do buffers work when H+ is removed?

Answer 6

→ If H+ ions are removed the weak acid will dissociate to increase the H+ ion concentration

Question 7

Why does the pH remain relatively stable with a buffer?

Answer 7

→ Any H+ formed by the addition of strong acid will react with the conjugate base to form a weaker acid

Question 8

What are buffers used for?

Answer 8

→ Resisting sharp changes in pH

Question 9

What are 3 examples of intracellular buffers?

Answer 9

→ Phosphate buffer system
→ Amino acids/ proteins
→ Haemoglobin (RBC)

Question 10

What are 2 examples of extracellular buffers?

Answer 10

→Bicarbonate buffer system

→ Plasma proteins

Question 11

What maintains blood homeostasis?

Answer 11

→ CO2 bicarbonate buffering system

Question 12

How does the level of CO2 in the body determine acidity?

Answer 12

→ CO2 + H20 ⇌ H+ + HCO3-
→ CO2 reacts with water to form bicarbonate
→ Bicarbonate dissociates to form H+ and HCO3-

Question 13

What happens during acidosis?

Answer 13

→ CO2 builds up in the blood
→ More carbonic acid is produced
→ H+ increases

Question 14

What happens during alkalosis?

Answer 14

→ CO2 is removed from the blood
→ Less carbonic acid
→ H+ decreases

Question 15

How do the lungs contribute to acid/base balance?

Answer 15

→ Regulate CO2 levels

Question 16

How can you diagnose respiratory distress?

Answer 16

→ ABG and pH

Question 17

What is blood pH proportional to?

Answer 17

→ pH ∝ log (HCO3-)/PaCO2

Question 18

What does the renal system control and what is the timeframe for this?

Answer 18

→ The concentration of bicarbonate ions

→ time frame (hours to days)

Question 19

What does the respiratory system control and what is the time frame for this?

Answer 19

→ The partial pressure of CO2

→ time frame ( minutes)

Question 20

What happens if PaCO2 increases?

Answer 20

→ pH decreases

Question 21

What happens if PaCO2 decreases?

Answer 21

→ pH increases

Question 22

What happens if HCO3- increases?

Answer 22

→ pH increases

Question 23

What happens if HCO3- decreases?

Answer 23

→ pH decreases

Question 24

What is the balance of CO2 and HCO3- like in acidosis?

Answer 24

→ CO2 is too high

→ HCO3- is too low

Question 25

What is respiratory acidosis?

Answer 25

→ CO2 is too high

Question 26

What is metabolic acidosis?

Answer 26

→ HCO3- is too low

Question 27

What is the balance of CO2 and HCO3- like in alkalosis?

Answer 27

→ CO2 is too low | → HCO3- is too high

Question 28

What is respiratory alkalosis?

Answer 28

→ CO2 is low

Question 29

What is metabolic alkalosis?

Answer 29

→ HCO3- is too high

Question 30

What are the causes of acidosis?

Answer 30

``` → Hypercapnia → Increased lactic acid → Increased ketone bodies → Decreased kidney acid excretion → Decreased HCO3- reabsorption → Diarrhoea ```

Question 31

What are the effects of acidosis?

Answer 31

``` → Tachypnoea → Muscular weakness → Headache → Confusion + coma → Cardiac arrhythmia → Hyperkalaemia ```

Question 32

What are the compensatory mechanisms for acidosis?

Answer 32

→ Hyperventilation | → Decrease in HCO3- excretion

Question 33

What are the causes of alkalosis?

Answer 33

→ Hypocapnia → Vomiting → Increased kidney acid excretion → Increased alkalotic agent consumption

Question 34

What are the effects of alkalosis?

Answer 34

``` → Bradypnoea → Muscular weakness, cramps, tetany → Headache, nausea → Lightheadedness, confusion + coma → Cardiac arrhythmia → Hypokalaemia ```

Question 35

What are compensatory mechanisms for alkalosis?

Answer 35

→ Hypoventilation | → Increased HCO3- excretion

Question 36

How can acidosis induce hyperkalaemia?

Answer 36

Acidosis increases the concentration of extracellular H+ ⇓ Decreases the concentration gradient ⇓ Less H+ excretion via the H+/ Na+ exchange ⇓ Decreased levels of Na+ affect the Na+/K+ exchange ⇓ Decreasing the K+ absorption into the cell ⇓ K+ accumulation in the serum is hyperkalaemia ⇓ Leads to cardiac arrhythmias and muscle weakness

Question 37

How can alkalosis induce cerebral vasoconstriction?

Answer 37

CO2 acts as a vasodilator in blood vessels ⇓ In alkalosis with decreased CO2 and H+ there is vasoconstriction in cerebral arteries ⇓ Decrease leads to headaches, lightheadedness, confusion + seizures