lecture 7 (renal)

Question 1

what causes a low pH?

Answer 1

• metabolic acidosis (by decrease in bicarb)
• respiratory acidosis (increased pCO2)

Question 2

what is the compensation for metabolic acidosis?

Answer 2

• increased ventilation
• decreased pCO2

Question 3

what is the compensation for respiratory acidosis?

Answer 3

• increased bicarb conc
• increased H+ secretion

Question 4

what occurs with a high pH?

Answer 4

• metabolic alkalosis (increased bicarb conc)
• respiratory alkalosis (decreased pCO2)

Question 5

what is the compensation for metabolic alkalosis?

Answer 5

• increased pCO2
• decreased ventilation

Question 6

what is the compensation for respiratory alkalosis?

Answer 6

• decreased HCO3- conc
• decreased H+ secretion

Question 7

what is the primary defect in respiratory acidosis?

Answer 7

• increase in PCO2

Question 8

what is the effect of respiratory acidosis?

Answer 8

• production of too much H+ and bicarbonate
• lowers pH
• high PCO2
• high HCO3-

Question 9

what are the causes for respiratory acidosis?

Answer 9

• obstructive airway diseases
• drugs which depress respiration

Question 10

what is the primary defect in respiratory alkalosis?

Answer 10

• decrease in PCO2

Question 11

what is the effect of respiratory alkalosis?

Answer 11

• high pH
• low HCO3-
• low PCO2

Question 12

what are the causes of respiratory alkalosis?

Answer 12

• hyperventilation
• asthma
• mechanical ventilation
• salicylate overdose (aspirin)

Question 13

what is the primary defect in metabolic acidosis?

Answer 13

• decreased bicarb conc

Question 14

what is the effect of metabolic acidosis?

Answer 14

• low pH
• low bicarb conc

Question 15

what are the causes of metabolic acidosis?

Answer 15

• gain of non-volatile acid (Ketoacidosis, diabetes, lactic acid, solvent abuse)
• loss of HCO3- (diarrhoea)
• decreased renal acid secretion

Question 16

what is the primary defect in metabolic alkalosis?

Answer 16

• increase in bicarb concentration

Question 17

what is the effect of metabolic alkalosis?

Answer 17

• high pH
• high HCO3-

Question 18

what are the causes of metabolic alkalosis?

Answer 18

• increased GI loss of protons (vomitting)
• increased renal loss of protons (hyperaldosteronism)
• hypokalaemia
• administration of HCO3-/citrate IV
• liquorice (pseudohyperaldosteronism)

Question 19

how does the body recover from the acid base disturbances?

Answer 19

• buffering any excess
• respiratory compensation
• renal compensation (transcription/translation of genes etc)
• correction of defect
  (work to minimise change in pH but cant correct the disorder)

Question 20

what is the compensation mechanism?

Answer 20

• making changes to allow the values to become closer to normal

Question 21

what is the acidosis respiratory compensation?

Answer 21

• increased ventilation decreases PCO2 and H+ conc

Question 22

what is the respiratory alkalosis compensation?

Answer 22

• decreased ventilation increases PCO2 and H+ conc

Question 23

what is the renal compensation for acidosis?

Answer 23

• increased H+ secretion and excretion
• all filtered HCO3- reabsorbed
• increased NH4+ excretion
• HCO3- production increased

Question 24

what is the renal compensation for alkalosis?

Answer 24

• H+ secretion inhibited
• HCO3- reabsorption reduced
• acid and NH4+ excretion reduced
• HCO3- secretion into urine

Question 25

what transporter removes bicarbonate from the cell via the apical membrane?

Answer 25

- pendrin - bicarbonate chloride transporter

Question 26

what is pH directly proportional to?

Answer 26

bicarbonate concentration / partial pressure of co2

Question 27

what is renal tubular acidosis (RTA) ?

Answer 27

- acidosis restyling form impaired H+ excretion from kidney

Question 28

what aerate two types of renal tubular acidosis?

Answer 28

type 1 = distal renal tubule acidosis type 2 = proximal renal tubule acidosis

Question 29

what occurs in type 1?

Answer 29

- defective H+ secretion

Question 30

what are examples causing type 1 distal tubule RTA?

Answer 30

- sjogren syndrome - defective HKA - increased nephron permeability - distal nephron dysfunction (diabetes, drugs affecting RAAS system)

Question 31

what occurs in type 2 RTA?

Answer 31

- impaired H+ secretion in PT so decreased HCO3- reabsorption - decreased plasma HCO3- causes acidosis

Question 32

what is the cause for type 2 RTA?

Answer 32

- general dysfunction

Question 33

what is the anion gap?

Answer 33

- difference in measured amount of anions in serum compared to the ions that are actually present - difference in concentration of major ECF cations and anions

Question 34

how is the anion gap calculated?

Answer 34

Na+ conc - (Cl- conc + HCO3- conc)

Question 35

what is the normal value for anion gap?

Answer 35

8 to 16 mEq/L

Question 36

what is the anion gap with acidosis from acid loading ?

Answer 36

- larger anion gap

Question 37

what is the anion gap with acidosis from bicarbonate loss ?

Answer 37

- larger anion gap

Question 38

what does an increase in anion gap indicate?

Answer 38

- progression or likelihood to progress in chronic kidney disease

Question 39

how does acidosis progress to chronic kidney disease?

Answer 39

- increased acid retention - causes decreased interstitial and intracellular pH - increased ammonia genesis ET1 and RAAS production - activation of complement, pro inflammatory and profibriotic mediators - tubule-interstitial injury and fibrosis - loss of functioning nephrons - chronic kidney disease progression - increased acid retention (loops to cause progression of kidney disease)

Question 40

what is the role of endothelin in kidney disease?

Answer 40

- podocyte foot process effacement, enhanced glomerular permeability = proteinuria - activation of proinflamamtory factors = inflammation - activation of fibrotic factors = fibrosis

Question 41

how does angiotensin II contribute to chronic kidney disease?

Answer 41

- elevation of intra-glomerular pressure = proteinuria - proliferation of tubular cells and fibroblasts = tubular atrophy - activation of proinflamamtory factor = inflammation - activation of fibrotic factors = fibrosis - tubule interstitial injury and fibrosis

Question 42

how does ammoniagenesis cause chronic kidney damage?

Answer 42

- activation of complement C3, C5b-9 and alternative complement cascade - increased production of pro inflammatory, proliferation an profibrotic mediators - proteinuria, inflammation, fibrosis - tubule interstitial injury and fibrosis