Acid Base Balance II

Question 1

Describe hypercapnia

Answer 1

high carbon dioxide

Question 2

What stimulates central chemoreceptors

Answer 2

hypercapnia, pH

Question 3

What is the main function of the central chemoreceptors

Answer 3

drive breathing

Question 4

Who identified that central chemoreceptors are stimulated by pH

Answer 4

Isidore Leusen

Question 5

Where are central chemoreceptors located

Answer 5

brain parenchyma

Question 6

What bathes the central chemoreceptors

Answer 6

brain extracellular fluid

Question 7

Which chemoreceptors are excretely expressed

Answer 7

central

Question 8

What cell type are central chemoreceptors

Answer 8

neuronal

Question 9

What is the blood brain barrier NOT permeable to

Answer 9

bicarbonate or hydrogen ions

Question 10

What is the MAIN stimulation for central chemoreceptors

Answer 10

increased CO2, therefore pH fall

Question 11

How does the BBB compensate for pH changes

Answer 11

can upregulate its permeability to bicarbonate

Question 12

Why is brain extracellular fluid capacity to buffer pH low

Answer 12

fewer proteins

Question 13

What is a drawback of brain extracellular fluid having low buffering capacity

Answer 13

small changes in CO2 will cause large pH changes

Question 14

What concentrations are affected in metabolic disorders

Answer 14

hydrogen and/or bicarbonate

Question 15

What is the impact of metabolic disorders compared to respiratory disorders on brain extracellular fluid pH

Answer 15

metabolic disorders change BECF pH by a very small amount compared to respiratory

Question 16

Where are central chemoreceptors located

Answer 16

ventrolateral medulla and brainstem nuclei

Question 17

What are the two central chemoreceptor populations

Answer 17

acid activated, acid inhibited

Question 18

What neurotransmitter is associated with acid activated central chemoreceptors

Answer 18

serotonin

Question 19

What neurotransmitter is associated with acid inhibited central chemoreceptors

Answer 19

GABA

Question 20

What can some sudden infant death babies lack

Answer 20

serotonergic neurones

Question 21

What defect might sudden infant death babies have

Answer 21

defect in central chemoreceptors

Question 22

What receptors are stimulated during respiratory acidosis

Answer 22

central and peripheral chemoreceptors

Question 23

Which receptors play the biggest role when oxygen levels are normal

Answer 23

central chemoreceptors

Question 24

Which receptors have the fastest response during respiratory acidosis

Answer 24

peripheral chemoreceptors

Question 25

Definition of normoxic

Answer 25

normal oxygen levels

Question 26

When does metabolic acidosis occur

Answer 26

extreme hyperventilation

Question 27

Describe carbon dioxide in metabolic acidosis

Answer 27

fall in partial pressure of CO2

Question 28

What drives the acute response in metabolic acidosis

Answer 28

peripheral chemoreceptors

Question 29

What is the effect of hyperventilation on pH

Answer 29

pH increases

Question 30

How does metabolic acidosis affect breathing rate

Answer 30

breathing rate increases

Question 31

What is the ONLY long term regulation of pH

Answer 31

renal mechanisms

Question 32

What are the 3 mechanism of the renal system for pH regulation

Answer 32

bicarbonate handling, urine acidification, ammonia synthesis

Question 33

What does bicarbonate handling mean

Answer 33

bicarbonate is reabsorbed

Question 34

Where is the majority of bicarbonate reabsorbed

Answer 34

90% in proximal tubule

Question 35

What enzyme catalyses the break down of carbonic acid

Answer 35

carbonic anhydrase

Question 36

What does base conservation mean

Answer 36

bicarbonate conservation

Question 37

What is the main contributer to base conservation

Answer 37

ammonia synthesis

Question 38

What can generate bicarbonate

Answer 38

renal epithelial cells

Question 39

What can undergo urine acidification

Answer 39

uric acid, creatinine

Question 40

Where does urine acidification occur

Answer 40

nearly all the way down the nephron

Question 41

TRUE or FALSE - ammonia is impermeable across the cell membrane

Answer 41

false - its permeable

Question 42

What does ammonia come from in renal cells

Answer 42

break down of glutamine

Question 43

What does ammonium allow the secretion of

Answer 43

hydrogen ions

Question 44

What does ammonia production prevent

Answer 44

acidification of the urine

Question 45

What increases during alkalosis

Answer 45

bicarbonate excretion, pH increases

Question 46

What decreases during alkalosis

Answer 46

plasma pH, H+ excretion

Question 47

What increases during acidosis

Answer 47

H+ excretion, plasma pH

Question 48

What stays the same during acidosis

Answer 48

bicarbonate excretion

Question 49

Describe carbon dioxide levels during respiratory alkalosis

Answer 49

CO2 decreases

Question 50

When is respiratory acidosis seen

Answer 50

lungs have a problem excreting CO2

Question 51

What diseases would have a respiratory acidosis

Answer 51

emphysema, chronic bronchitis

Question 52

When would metabolic acidosis occur

Answer 52

ingestion of acid, loss of alkaline fluid, diarrhoea, cholera

Question 53

What is stimulated during metabolic acidosis

Answer 53

central chemoreceptors to increase ventilation

Question 54

In what disorder does the renal system not contribute to

Answer 54

metabolic alkalosis

Question 55

Where does compensation come from for metabolic alkalosis

Answer 55

respiratory system

Question 56

What is a mixed disorder

Answer 56

more than one disorder e.g. respiratory and metabolic acidosis

Question 57

Examples of mixed disorders

Answer 57

Alcoholics, asthma, COPD, salicylate poisoning

Question 58

Which is the most life threatening mixed disorder

Answer 58

asthma

Question 59

What mix disorders do COPD patients have

Answer 59

respiratory acidosis and metabolic alkalosis

Question 60

What mix disorders do patients with salicylate poisoning have

Answer 60

respiratory alkalosis and metabolic acidosis