ACID AND BASE BALANCE

Question 1

proton donor (the substance that liberates hydrogen ion)

Answer 1

acid

Question 2

proton acceptor (the substance that accepts hydrogen ion)

Answer 2

base

Question 3

concentration of free hydrogen ion in the body

Answer 3

pH 7.4

Question 4

normal H+ concentration in the extracellular fluid (ECF)

Answer 4

38 to 42
nM/L.

Question 5

An increase in H+ ion concentration ____ the pH (acidosis)

Answer 5

decreases

Question 6

reduction in H+
concentration ____ the pH (alkalosis)

Answer 6

increases

Question 6

An increase in pH by onefold requires a ____ in H+ concentration

Answer 6

tenfold decrease

Question 6

indirect method determine the acid-base status in the ECF

Answer 6

Henderson-Hasselbalch equation

Question 7

bicarbonate ions

Answer 7

𝐻𝐶𝑂3−

Question 8

𝐻𝐶𝑂3−

Answer 8

bicarbonate ions

Question 9

pH of plasma is also determined by using

Answer 9

pH meter

Question 10

Normal acid-base ratio

Answer 10

1:20

1 CO2 (from 𝐻2𝐶𝑂2): 20 𝐻𝐶𝑂3−

Question 11

two types of acids are produced in the body

Answer 11

1. Volatile acids
2. Non-volatile acids.

Question 12

are derived from 𝐶𝑂2

Answer 12

Volatile acids

Large quantity of 𝐶𝑂2 is produced during the
metabolism of carbohydrates and lipids. This 𝐶𝑂2 is not a threat because it is almost totally
removed through expired air by lungs.

Question 13

produced during the metabolism of other nutritive substances
such as proteins

Answer 13

Non-volatile Acids

real threat

Question 14

sulfuric acid is produced during the metabolism of sulfur containing amino acids such as

Answer 14

cysteine and methionine

Question 15

is produced during the metabolism of lysine,
arginine and histidine.

Answer 15

hydrochloric acid

Question 16

the body has three mechanisms
to regulate acid-base status:

Answer 16

1. Acid-base buffer system, which binds free H+
2. Respiratory mechanism, which eliminates 𝐶𝑂2
3. Renal mechanism, which excretes H+ and conserves the bases (HCO3 –)

Question 17

the fastest mechanism and it
readjusts the pH within seconds.

Answer 17

acid-base buffer system

Question 18

mechanism does it in minutes

Answer 18

respiratory mechanism

Question 19

slower and it takes few hours to few days to bring the pH back to normal

Answer 19

renal mechanism

Question 20

most powerful mechanism than the other two in
maintaining the acidbase balance of the body fluids

Answer 20

renal mechanism

Question 21

acid-base buffer system is the combination of a?

Answer 21

weak acid (protonated substance)
and a base – the salt (unprotonated substance).

Question 22

acts immediately to prevent the changes in pH

Answer 22

Buffer system

Question 23

Buffer system maintains pH by ____

Answer 23

binding with free H+.

Question 24

Body fluids have three types of buffer systems

Answer 24

 Bicarbonate buffer system  Phosphate buffer system  Protein buffer system.

Question 25

buffer system is present in ECF (plasma).

Answer 25

Bicarbonate buffer system

Question 26

consists of the protonated substance, **carbonic acid (H2CO3)** which is a weak acid and the unprotonated substance, **HCO3** –, which is a weak base. HCO3 – is in the form of salt, i.e. sodium bicarbonate (NaHCO3).

Answer 26

Bicarbonate buffer system

Question 27

Bicarbonate buffer system prevents the fall of pH in a fluid to which a strong acid like ?

Answer 27

hydrochloric acid (HCl) is added. ## Footnote This is because the H+ dissociated from HCl combines with H𝐶𝑂3 – of NaH𝐶𝑂3 and forms a weak H2CO3. This H2CO3 in turn dissociates into 𝐶𝑂2 and 𝐻2𝑂

Question 28

buffer system also prevents the increase in pH in a fluid to which a strong base like sodium hydroxide (NaOH) is added

Answer 28

Bicarbonate buffer system ## Footnote As sodium bicarbonate is a very weak base, its association with H+ is poor. So the rise in pH of the fluid is very mild.

Question 29

pK of bicarbonate buffer system

Answer 29

6.1 ## Footnote Bicarbonate buffer system is not powerful like the other buffer systems, large difference between ECF pH of 7.4

Question 30

Concentration of H𝐶𝑂3 – is regulated by ## Footnote BBS

Answer 30

kidney

Question 31

the concentration of 𝐶𝑂3 is regulated by the ## Footnote BBS

Answer 31

respiratory system

Question 32

consists of a **weak acid**, the dihydrogen phosphate (**H2PO4** – protonated substance) in the form of sodium dihydrogen phosphate (**NaH2PO4**) and the *base*, hydrogen phosphate (*HPO4* – unprotonated substance) in the form of disodium hydrogen phosphate (*Na2HPO4*)

Answer 32

Phosphate Buffer System

Question 33

buffer system is useful in the intracellular fluid (ICF), in red blood cells or other cells, as the concentration of phosphate is more in ICF than in ECF

Answer 33

Phosphate Buffer System

Question 34

Phosphate buffer system pK

Answer 34

6.8 ## Footnote more powerful than BBS as it is close to the pH of the body fluids, i.e. 7.4

Question 35

phosphate buffer is useful in ____ also. It is because more phosphate ions are found in tubular fluid.

Answer 35

tubular fluids of kidneys

Question 36

In the red blood cells, the potassium ion concentration is higher than the sodium ion concentration. So, the elements of phosphate buffer inside the red blood cells are in the form of?

Answer 36

potassium dihydrogen phosphate (KH2PO4) and dipotassium hydrogen phosphate (K2HPO4).

Question 37

buffer systems are present in the blood; both in the plasma and erythrocytes.

Answer 37

Protein Buffer System

Question 38

Elements of proteins, which form the weak acids in the plasma are:

Answer 38

a. C-terminal carboxyl group, N-terminal amino group and side-chain carboxyl group of glutamic acid b. Side-chain amino group of lysine c. Imidazole group of histidine.

Question 39

Protein buffer systems in plasma are ____ because of their high concentration in plasma and because of their pK being very close to 7.4.

Answer 39

more powerful

Question 40

is the most effective protein buffer and the major buffer in blood

Answer 40

Hemoglobin

Question 41

Due to its high concentration than the plasma proteins, hemoglobin has about ____ more buffering capacity than the plasma proteins.

Answer 41

six times

Question 42

The ____ hemoglobin is a more powerful buffer than ____ hemoglobin because of the higher pK.

Answer 42

deoxygenated oxygenated ## Footnote When a hemoglobin molecule becomes deoxygenated in the capillaries, it easily binds with H+, which are released when CO2 enters the capillaries. Thus, hemoglobin prevents fall in pH when more and more CO2 enters the capillaries.

Question 43

play an important role in the maintenance of acid-base balance by removing CO2 which is produced during various metabolic activities in the body

Answer 43

Lungs

Question 44

H2CO3 splits into

Answer 44

carbonic acid H+ + HCO3-

Question 45

CO2 is blown off by

Answer 45

ventilation ## Footnote When metabolic activities increase, more amount of CO2 is produced in the tissues and the concentration of H+ increases as seen above. Increased H+ concentration increases the pulmonary ventilation (hyperventilation) by acting through the chemoreceptors. Due to hyperventilation, the excess of CO2 is removed from the body.

Question 46

maintains the acid-base balance of the body by the secretion of H+ and by the retention of HCO3

Answer 46

kidney

Question 47

reduction in pH (increase in H + concentration) below normal range.

Answer 47

Acidosis

Question 48

Acidosis is produced by

Answer 48

1. Increase in partial pressure of CO2 in the body fluids particularly in arterial blood 2. Decrease in HCO3 – concentration

Question 49

is the increase in pH (decrease in H+ concentration) above the normal range.

Answer 49

Alkalosis

Question 50

Alkalosis is produced by:

Answer 50

1. Decrease in partial pressure of in the arterial blood 2. Increase in HCO3 – concentration

Question 51

Since the partial pressure of CO2 (pCO2) in arterial blood is controlled by lungs, the acid-base disturbances produced by the change in arterial pCO2 are called the?

Answer 51

respiratory disturbances

Question 52

the disturbances in acid-base status produced by the change in HCO3 – concentration are generally called the?

Answer 52

metabolic disturbances.

Question 53

acid-base disturbances are:

Answer 53

1. Respiratory acidosis 2. Respiratory alkalosis 3. Metabolic acidosis 4. Metabolic alkalosis.