Basics of acid base balance Flashcards Preview

Kidneys and Hormones > Basics of acid base balance > Flashcards

Flashcards in Basics of acid base balance Deck (37):
1

Why is it important to regulate blood pH?

Many chemical reactions are pH sensitive

Excess protons will bind to proteins and change their charge

2

What will excess protons do to proteins?

Bind to them and change their charge

3

Body reactions produce enough acid to make a pH of what?

1

4

What two components make a good buffer?

Weak acid and weak conjugate base

5

What are the two types of buffer in our bodies?

Intracellular

Extracellular

6

What are examples of intracellular buffers?

Proteins

Phosphates

Haemoglobin

7

What is the main buffer of RBCs?

Haemoglobin

8

What are examples of extracellular buffers?

Bicarbonate ions

Phosphate ions

Proteins

9

What are the two types of acids you can find in the body?

Volatile

Non-volatile

10

What are volatile acids?

Acids you can get rid off

11

What is the main buffer in the blood?

Bicarbonate ions

12

How is bicarbonate made?

When the unstable intermediate carbonic acid, that is made from the reaction between carbon dioxide and water, breaks down

13

What are non-volatile acids?

Acids you can't get rid of (buffer)

14

What is an example of a non-volatile acid?

Sulphate derived from the metabolism of sulphur-containing amino acids

15

How are non-volatile acids removed from the body?

Via the kidneys

16

What gas is central to the control of pH?

Carbon dioxide

17

Protons determine the pH of blood

TRUE or FALSE

TRUE

18

How is carbon dioxide controlled in the body?

Negative feedback loop

Chemoreceptors sense the proton concentration of the blood

Increase in ventilation counterracts the increase in pH

19

What is the result of increasing breathin rate on the pH of the blood?

Increasing breathing rate

Reduces carbon dioxide concentration

Less carbonic acid is produced

Less protons are produced

Reversible reaction is pushed to form more carbon dioxide

20

Why do we need protein buffers?

Hydrogen ions are transported across membranes

21

What is the composition of RBC cell membranes?

50% proteins

33% Hb

22

What parts of the proteins act as buffers?

Carboyl group

Amino groups

23

What is an important amino acid found in Haemoglobin?

Histidine

Hb = 8% histidine

24

Why is histidine an important component of Hb?

Histidine's pKa (buffering capacity) = 6

This means it works best at pH 6

Amino acid with pKa closest to the physiological pH

25

How does Hb buffer?

Somatic cells release carbon dioxide into the extracellular fluid

Carbon dioxide enters RBC and forms carbonic acid

Carbonic acid dissociates releasing protons

Protons are charged and so cannot leave the cell

Oxyhaemoglobin exchanges oxygen for a proton

Oxygen is released and enters somatic cells

26

Does chemical buffering work in the long term?

No

Molecules get oversaturated and don't work anymore

27

What is a technique used by the body to spread the effects of hydrogen ion changes?

Buffer proteins are found spread throughout the body

28

What causes disturbances of pH?

Respiratory acidosis

Respiratory alkalosis

Metabolic acidosis

Metabolic alkalosis

29

What is respiratory acidosis?

Insufficient removal of carbon dioxide

Due to inadequate breathing or high carbon dioxide concentration in the air

Rise in CO2 in plasma = more carbonic acid produced = more protons

30

What is respiratory alkalosis?

Excess removal of carbon dioxide

Hyperventilation or high altitude

Fall in plasma carbon dioxide = less carbonic acid produced = less protons

31

What is metabolic acidosis?

Excess production of non-volatile acids

Due to voluntary ingestion of methanol

Or loss of base from the gut during diarrhea

Fall in plasma pH and increase in bicarbonate concentration

32

What is metabolic alkalosis?

Excess non-volatile bases

Due to vomiting

33

What causes respiratory acidosis?

Decreased ventilation

Increased carbon dioxide concentration in the air

34

What causes respiratory alkalosis?

Increased ventilation

High altitude

35

What causes metabolic acidosis?

Loss of base during diarrhea

Consumption of methanol

36

What causes metabolic alkalosis?

Vomiting

37

How does consumption of methanol lead to metabolic acidosis?

Methanoic acid results in increased lactic acid

Since the cytochrome in mitochondria is inhibited