Acid base

Question 1

What does ph stand for

Answer 1

Potential of hydrogen

Question 2

What is the ph of gastric juice

Answer 2

2

Question 3

What is the ph of inside of small intestine

Answer 3

8

Question 4

State some ways in which acid can be produced in the body

Answer 4

• Breakdown of food esp protein
• • CO2 metabolised and forms carbonic acid with water
• Acids resulting from other metabolic activity such as lactic acid in exercise

Question 5

Name the 3 ways that the body can regulate acid base

Answer 5

• Chemical buffers in blood and interstitial fluid
• Respiratory centre in the brain stem
• Renal mechanism

Question 6

Define buffer

Answer 6

Solution that can resist pH change upon the addition of an acid or a base

Question 7

What are the main buffer systems in the body

Answer 7

• Bicarbonate
• Proteins
• Phosphates

Question 8

What proteins are most commonly used as a buffer system

Answer 8

Haemoglobin in blood

Albumin in plasma

Question 9

Can chemical buffers eliminate acids or bases from the body

Answer 9

No

Question 10

Does acidemia lead to hypo/ hyper kalaemia

Answer 10

Hyper

Question 11

Why does acidemia lead to hyperkalaemia

Answer 11

Cells take in more hydrogen so potassium is displaced

Question 12

Why do alkalosis lead to hypokalaemia

Answer 12

Because hydrogen goes out of the cell so potassium mvoes in

Question 13

Does anion gap measure levels in the blood or the plasma

Answer 13

Plasma

Question 14

What are the cations used in anion gap

Answer 14

Unmeasured cations
K+
Na+

Question 15

What are the anions used in the anion gap

Answer 15

Unmeasured anions
HCO3-
Cl-

Question 16

What is meant by the magic 4

Answer 16

way to remember levels of electrolytes in plasma
K+=4
Na+=140
HCO30=24
Cl-= 104

Question 17

Name some of the unmeasured cations

Answer 17

Calcium
Magnesium
Proteins

Question 18

Name some of the unmeasured anions

Answer 18

Phosphates
Sulfates
Proteins

Question 19

What is a normal anion gap

Answer 19

8-12mEg/L

Question 20

How do you calculate anion gap

Answer 20

Na+-(Cl-+HCO3-)

Question 21

Why does a loss of bicarbonate causing acidosis not lead to a change in anion gap

Answer 21

• Chloride compensates for loss of bicarbonate

- There is an exchange of chloride and bicarbonate

Question 22

What is it called when there is a surge of chloride leading to acidosis

Answer 22

Hyperchloremic acidosis

Question 23

What are the causes of normal gap acidosis?

Answer 23

‘gut stuff’ leading to bicarb loss

• Severe diarrhoea
• Laxative abuse
• Villous adenoma
• Others

Question 24

Name some causes of normal gap acidosis

Answer 24

• Bicarbonate loss

- Reduced kidney H+ excretion

Question 25

Why does reduced kidney H+ secretion lead to normal gap acidosis

Answer 25

If kidneys are not able to excrete acids efficiently, more HCO3- is needed to buffer them leading to drop in bicarbonate (lost into carbonic acid)

Question 26

Causes of reduced kidney H+ excreted

Answer 26

Renal failure

Question 27

How far up can the elevated anion gap go

Answer 27

24mEg/L

Question 28

What are the causes of elevated gap acidosis

Answer 28

Too much acid or not enough bicarbonate is being produced: - Ketoacidosis - Lactic acidosis - Also severe renal failure

Question 29

Which unmeasured anion contributes to the majority of the value of anion gap

Answer 29

Albumin

Question 30

What causes low gap acidosis

Answer 30

Albumin dropped leading to surge in HCO3- and Cl- - Haemorrhage - Nephrotic syndrome - Intestinal obstruction - Liver cirrhosis

Question 31

What kind of acids do the lungs deal with

Answer 31

CO2

Question 32

What organ can prevent metabolic acidosis

Answer 32

Kidney

Question 33

Which 2 tasks must the kidney complete to control acid base balance

Answer 33

- Reabsorption of all filtered bicarbonate | - Excrete the daily acid load

Question 34

Where is 70-90% of the bicarbonate reabsorbed

Answer 34

Proximal convuluted tubule

Question 35

Where is 10-30% of the bicarbonate reabsorbed

Answer 35

Throughout rest of the nephron (after PCT)

Question 36

Which enzyme breaks HCO3 into CO2 and OH

Answer 36

Carbonic anhydrase

Question 37

Where in the kidney does active excretion of H+ happen

Answer 37

Various parts of the distal kidneys

Question 38

What do alpha intercalated cells secrete and reabsorb

Answer 38

Secretes acid | Reabsorbs HCO3-

Question 39

What pumps does alpha intercated cell use to excrete acid

Answer 39

H+ ATPase pump | H+/K+ exchanger

Question 40

What do beta intercalated cells excrete/ absorb

Answer 40

Secretes HC03- | Reabsorbs acid

Question 41

How do renal tubule cells act during acidosis

Answer 41

- Need to get rid of H+ into the lumen using sodium transporter - Bicarbonate moves into the cell

Question 42

Which 2 systems are used to allow excretion of acid

Answer 42

HPO42- buffer and ammonium

Question 43

Which pathways is used by kidneys to produce bicarbonate

Answer 43

Glutimate pathway

Question 44

How do renal cells act during alkalosis

Answer 44

Tubular cells secrete bicarbonate ions and reclaim hydronium to acidify the body This uses separate ATPase K+ traded for H+

Question 45

What are the stimuli for HCO3- reabsorption in PCT

Answer 45

Low ph Low K+ Angiotensin II

Question 46

What does drop in ph or increase in aldosterone do to the collecting duct

Answer 46

- Sodium reabsorption | - Displaced by H+ and K+

Question 47

What does the Henderson-Hasselbach equation find

Answer 47

- pH of buffer solution | - ratio of conjugate base: acid

Question 48

pH=

Answer 48

PKa + log (conjugate base)/ (acid)

Question 49

What does pKa=

Answer 49

-log( equilibrium constant)