Physiology 8

Question 1

what does the body do the maintain pH levels?

Answer 1

We need to maintain the ratio between HCO3 (bicarbonate) and carbon dioxide

Question 2

How does the body control levels of carbon dioxide?

Answer 2

by using the respiratory system

Question 3

how does the body control levels of bicarbonate?

Answer 3

by using the kidneys

Question 4

What is respiratory acidosis?

Answer 4

A decrease in pH caused by the respiratory system

Question 5

What is the cause of respiratory acidosis?

Answer 5

An increase in CO2

Question 6

what are the acute causes of CO2 retention?

Answer 6

hypoventilation, barbiturates, opioids, obstruction.

Question 7

What are the chronic causes of CO2 retention?

Answer 7

COPD, asthma, bronchitis

Question 8

what is the response to respiratory acidosis?

Answer 8

An increase in PCO2 should be compensated by an increase in HCO3 by the kidneys.

Question 9

In respiratory acidosis how do we get an increase in HCO3?

Answer 9

the increase in CO2 causes an increase in H+ ions that can be used to reabsorb and create new bicarbonate.

Question 10

What is respiratory alkalosis?

Answer 10

this is an increase in pH caused by the respiratory system.

Question 11

What causes respiratory alkalosis?

Answer 11

a decrease in PCO2

Question 12

what causes an acute decrease in PCO2?

Answer 12

hyperventilation, aspirin, going to high altitudes

Question 13

what causes a chronic decrease in PCO2?

Answer 13

living at high altitudes

Question 14

How does the kidneys compensate to respiratory alkalosis?

Answer 14

The reduction in PCO2 is compensated. by the kidneys reducing HCO3 (this is easy because theres less H+ to create bicarbonate anyway)

Question 15

What is metabolic acidosis?

Answer 15

This is a decrease in pH caused by the kidneys.

Question 16

what causes metabolic acidosis?

Answer 16

a reduction in HCO3 from the kidneys

Question 17

What causes a reduction in HCO3 from the kidneys?

Answer 17

the kidneys not reabsorbing or producing HCO3, more HCO3 being used as a buffer (if theres more CO2), diabetic ketoacidosis, kidney failure, diarrhoea

Question 18

What is the respiratory response to metabolic acidosis?

Answer 18

the respiratory system decreases PCO2 in response to a decreased HCO3, it does this by blowing off more CO2.

Question 19

What is kussmal breathing?

Answer 19

This is when the respiratory system increases depth of breathing to blow off more carbon dioxide - it is a sign of metabolic acidosis - by either chronic kidney disease or diabetic ketoacidosis.

Question 20

How does the respiratory system delay the correction of the metabolic acidosis by the kidneys?

Answer 20

because the respiratory system blows off more carbon dioxide to maintain the pH, this reduces the H+ available to create more HCO3 so it takes longer for the kidneys to increase HCO3 to correct the original problem

Question 21

What is metabolic alkalosis?

Answer 21

this is an increase in pH due to the kidneys increase in HCO3 (its more likely to be caused by a reduction in H+)

Question 22

what are causes of metabolic alkalosis?

Answer 22

(reduction in H+): vomiting, aldosterone, liquorice.

Question 23

how does the respiratory system compensate to metabolic alkalosis?

Answer 23

increase the PCO2 (reduced breathing)

Question 24

what is the difference between acute and chronic metabolic alkalosis and acidosis?

Answer 24

there is none - because compensation via the respiratory system is instant (occurs within minutes)

Question 25

what is the difference between acute and chronic respiratory acidosis and alkalosis?

Answer 25

the acute kidney response:
the only thing the kidneys can do initially is lose protons via titratable acids
the chronic kidney response: the kidney can make glutamine to be created into NH3 to be used to remove H+

Question 26

What pH is worse, acute or chronic respiratory problems?

Answer 26

The acute pH is always more dramatically affected, because the kidneys take a while to properly respond and compensate

Question 27

What happens when you vomit or have diarrhoea?

Answer 27

You lose both acid and alkali but you will become alkalotic

Question 28

Why do you become alkaloitic in vomiting or diarrhoea?

Answer 28

because your body volume reduces - this increases renin and this increases aldosterone - aldosterone increases sodium reabsorption and increases potassium excretion and increased Hydrogen excretion.
the increased hydrogen excretion causes the alkalosis.