Acid/Base

Question 1

normal pH of the body

Answer 1

7.38-7.42; slightly alkaline

Question 2

pH values of gastric secretion

Answer 2

1.0-3.5

Question 3

pH values of urine

Answer 3

4.5-8.0

Question 4

alkalosis

Answer 4

• high pH/low H+
• hyperexcitability in sensory neurons and muscles
• sustained respiratory muscle contraction

Question 5

acidosis

Answer 5

very low pH/excess H+

-CNS depression, confusion, coma

Question 6

Largest source of acid on a daily basis is..

Answer 6

CO2 from aerobic metabolism

Question 7

pH homeostasis depends on what 3 mechanisms?

Answer 7

• buffers (first line of defence)
• ventilation (75% of disturbances)
• renal regulation of H+ and HCO3- (slowest)

Question 8

buffer systems include..

Answer 8

proteins, phosphate ions, and HCO3-

Question 9

intracellular buffers

Answer 9

cellular proteins (hemoglobin), phosphate ions

Question 10

the most important extracellular buffer system

Answer 10

HCO3-

Question 11

Plasma HCO3- conc. is approx. _______x conc. as plasma H+

Answer 11

600 000

Question 12

What senses changes in plasma PCO2 and/or H+?

Answer 12

peripheral and central chemoreceptors; which signal to respiratory control center to adjust ventilation

Question 13

Alterations in ventilation can..

Answer 13

correct disturbances in acid/base balance as well as cause them

Question 14

How does the kidney handle the remaining 25% of pH disturbances?

Answer 14

• directly, by altering the rates of excretion or reabsorption of H+
• indirectly by changing the rate at which HCO3- buffer is reabsorbed or excreted

Question 15

kidney uses what kind of buffers

Answer 15

ammonia and phosphate buffers

Question 16

proximal tubule

Answer 16

secreted H+ and reabsorbs HCO3-

Question 17

distal nephron

Answer 17

controls acid excretion

Question 18

initial portion of the collecting duct

Answer 18

plays a significant role in fine regulation of acid-base balance

Question 19

Type A intercalated cells

Answer 19

function in acidosis to increase H+ secretion and HCO3- and K+ are reabsorbed; hyperkalemia

Question 20

Type B intercalated cells

Answer 20

function in alkalosis to increase H+ reabsorption and HCO3- and K+ secretion; hypokalemia

Question 21

acid-base disturbances may be

Answer 21

respiratory or metabolic

Question 22

respiratory induced changes in pH must be resolved via..

Answer 22

renal mechanism

Question 23

respiratory acidosis

Answer 23

when alveolar hypoventilation results in CO2 retention and elevated plasma CO2

Question 24

respiratory alkalosis

Answer 24

less common; occurs as a result of hyperventilation in absence of increased metabolic CO2 production

Question 25

respiratory acidosis compensation by..

Answer 25

H+ excretion, HCO3- reabsorption

Question 26

respiratory alkalosis compensation by…

Answer 26

HCO3- excretion and H+ reabsorption

Question 27

metabolic acidosis

Answer 27

when dietary or metabolic input of H+ exceeds H+ excretion

Question 28

ketoacidosis

Answer 28

results from excessive breakdown of fats and some amino acids

Question 29

metabolic alkalosis common causes

Answer 29

• excessive committing of acidic stomach contents

- excessive ingestion of bicarbonate-containing antacids

Question 30

renal response to metabolic alkalosis

Answer 30

HCO3- excreted and H+ reabsorbed