Lecture 41: Acid base II

Question 1

In order to maintain acid-base balance the kidneys must:

Answer 1

• replace the bicarbonate that has been filtered by the glomerulus
• form new bicarbonate to replace that consumed in the excretion of non-volatile acids

Question 2

The kidneys handle bicarbonate in 3 different ways which are:

Answer 2

• reabsorption of filtered HCO3
• replacement of bicarbonate consumed in excretion of non-volatile acids
• excretion of excess bicarbonate

Question 3

Acidosis is when the pH is:
- what does acidosis result in?

Alkalosis is when the pH is:
- what does alkalosis result in:

What senses the change in pH

Answer 3

Acidosis is when the pH is below 7.35
- hypoventilation = increase in H+, decreased loss of CO2 as you exhale less

Alkalosis is when the pH is above 7.45
- hyperventilation = results in loss of H+ as you exhale CO2

Change in pH is sensed by the carotid sinus and the aortic arch chemoreceptors

Question 4

What is metabolic acidosis?

Answer 4

= due to increased H+ or decreased HCO3-

• occurs when you have uncontrolled diabetes or during starvation
• results in abnormally large amounts of acids entering the blood

Question 5

What is metabolic alkalosis?

Answer 5

= due to the deceased H+ or increased HCO3- ; too much HCO3-

- occurs due to the ingestion of large amounts of alkali or due to excess vomiting

Question 6

What is respiratory acidosis?

What is respiratory alkalosis?

Answer 6

= too much CO2, hypoventilation; is caused when carbonic acid is in excess
= too little CO2, hyperventilation; excess loss of carbonic acid

Question 7

How does the renal system and respiratory system compensate for acidosis?

Answer 7

Renal system:

• Glomerular filtration rate is decreased to reduce the filtered load of HCO3-
• The amount of HCO3- filtered is decreased
• H+ secretion is increased

Respiratory system
Respiration rate is increased = hyperventilation which results in a decrease in PCO2 of the plasma

Question 8

How does the renal system and respiratory system compensate for alkalosis?

Answer 8

The renal systems:

• Glomerular filtration rate is increased to increase the filtered load of HCO3-
• The amount of HCO3- excreted via the filtrate is increased i
• H+ secretion is decreased

The respiratory system:
Respiration rate is decreased = hypoventilation which results in an increase in the PCO2 of the plasma