Acid-Base (pH) Balance Overview + Buffer Systems

Question 1

acid-base balance

Answer 1

describes balance of H+ ions in blood aka pH balance

Question 2

normal pH range of arterial blood

Answer 2

7.35 - 7.45

Question 3

higher concentration of H+ means

Answer 3

substance is more acidic –> lower pH

Question 4

importance of maintaining constant pH in blood

Answer 4

enzymes (specialized proteins that control rt of metabolic reactions) are very sensitive to the pH , so blood pH outside a normal range inhibits enzymes’ normal functioning

Question 5

pH of venous blood + interstitial fluid

Answer 5

more acidic than arterial blood because cellular metabolism produces acidic waste materials

Question 6

3 systems controlling blood acidity

Answer 6

1. chemical buffer systems
2. brain stem respiratory center
3. renal system

Question 7

pH indicating alkalosis

Answer 7

pH > 7.45

Question 8

pH indicating acidosis

Answer 8

pH < 7.35

Question 9

anion

Answer 9

negatively charged ion

Question 10

cation

Answer 10

positively charged ion

Question 11

3 major buffer systems of body

Answer 11

1. bicarbonate system
2. phosphate system
3. protein system

Question 12

bicarbonate system

Answer 12

• main buffer of plasma and interstitial fluid
• fast acting (within seconds)
• composed of:
  carbonic acid (H2CO3) and bicarbonate ion (HCO3 -)

Question 13

phosphate system

Answer 13

• buffer of urine + intracellular fluid
• fast acting (within seconds)
• composed of:
  phosphoric acid (H2PO4) + hydrogen phophate ion (HPO3 -2)

Question 14

protein system

Answer 14

• main buffer of intracellular fluid
• fast acting (within seconds)
• 3x buffering capacity of other buffer systems (because of high protein concentrations in cells)
• composed of:
  amino acids + hemoglobin + plasma proteins

Question 15

buffers are a combination of

Answer 15

weak acid + its anion
OR
weak base and its cation

Question 16

how buffers work

Answer 16

buffers minimize pH changes

if an acid is introduced:
the buffers weak anion or weak base binds w/free H+ from the acid –> acid can’t lower pH

if base is introduced:
weak acid or weak cation binds with OH- from base –> base can’t raise pH