L16- Acid-Base Homeostasis Flashcards Preview

EMS- mod > L16- Acid-Base Homeostasis > Flashcards

Flashcards in L16- Acid-Base Homeostasis Deck (22):
1

What buffering systems are in place to try to keep balance?

Haemoglobin

Bicarbonate

Phosphate

Proteins

Ammonia

Misc organic acids

2

Normal range of pH?

7.45- 7.35

3

What are the sites of Acid-base metabolism

Lungs

Kidneys

GI tract

Liver

4

What direction does the O2-Haemoglobin dissociation curve when there is increased 2,3 DPG

To the RIGHT

An increased concentration of BPG in red blood cells favours formation of the T, low-affinity state of hemoglobin and so the oxygen-binding curve will shift to the right.

5

What direction does the O2-Haemoglobin dissociation curve when there is increased temperature?

To the RIGHT

Increasing temperature will weaken and denature the bond between an oxygen and a hemoglobin which in turn decreases the concentration of the oxyhemoglobin

6

What direction does the O2-Haemoglobin dissociation curve when there is acidosis?

To the RIGHT

decrease in blood pH, will result in haemoglobin proteins releasing their load of oxygen

7

What are proteins catabolised to in the Liver?

proteins catabolised to NH4+ and HCO3 -

8

Why can Severe Liver Failure cause NH4+ toxicity

Because the liver uses it for the reaction:
NH4+ + CO2 --X--> Urea + H+

Therefore a build of NH4+ can cause metabolic alkalosis

9

Causes of Metabolic Acidosis

Increased H+ formation

Acid ingestion

Reduced renal H+ excretion

Loss of bicarbonate

10

Causes of Metabolic Alkalosis

Generation of bicarbonate by gastric mucosa

Renal generation of HCO3- in Hypokalaemia

Administration of bicarbonate

11

Consequences of Metabolic alkalosis

K+ ---> Cells and Urine
PO4 ---> Cells
Respiratory Suppression

12

Reasons for Respiratory Acidosis

1: inadequate ventilation

2: parenchymal lung disease

3: inadequate perfusion

13

Reasons for Respiratory Alkalosis

Increased CO2 excretion due to excessive ventilation producing alkalosis

14

What can lead to increase H+ formation

ketoacidosis, diabetic or alcoholic
lactic acidosis
poisoning
inherited organic acidoses

15

What is Diabetic keto-acidosis

hyperglycaemia

osmotic diuresis ---> to pre-renal uraemia

hyperketonaemia

increased FFA
---> all lead to acidosis

16

What is Lactic acidosis ?

a form of metabolic acidosis due to the inadequate clearance of lactic acid from the blood

17

What is meant by a high anion gap?

metabolic acidosis

caused generally by the body producing too much acid or not producing enough bicarbonate

18

Process of acidosis in an alcoholic

There is NAD+ depletion (due to lack of thiamine)

Thiamine is pyruvate dehydrogenase co-factor

Inc Glycolysis for ATP production

(also another factor leading to acidosis is vomiting!)

19

Does high lactate = lactic acidosis ?

In alkalosis
1. increased glycolysis

2. reduced O2 delivery due to shift in O2 dissociation curve

3. Lactate induced vasoconstriction
impaired mitochondrial respiration

O2 debt due to # 2
1. further anaerobic lactate production
Hyperventilation

20

status asthmaticus

a severe condition in which asthma attacks follow one another without pause

21

What can be a cause of Reduced H+ excretion ?

renal tubular acidosis (kidneys fail to excrete acids into the urine, which causes a person's blood to remain too acidic)

generalised renal failure

22

What can Renal Failure lead to (ions etc)?

Lead to REDUCED VOLUME OF NEPHRONS

Increased bicarbonate loss

Reduced NH4+ excretion

Therefore more NH4+ to liver for urea + H+ synthesis