Acid-Base Balance Flashcards
Normal H+ conc is….., pH of arterial b is…..& of venous is…..
pH range which is compatible with life is……(for few hrs)
40 nEq/L (range 45-35)
7.4 (r7.35-7.45)
7.35
6.8-8
Describe effect of changes in H+ conc on body chemistry
- Changes in excitability of nerve and muscle cells, inc H+ causes depression of CNS & vice versa
- Affects enzymatic activity & disturb metabolism
- Influences potassium level
Mention sources of blood H+
- Volatile acids: carbonic acid formed by cellular oxidation
- Non-volatile acids: inorganic (dietary protein break down produce sulphuric & phosphoric acid), organic (resukt from intermediary metabolism)
The 1st line of defence against changes in pH is…….acts within….., its efficiency is……
Chemical buffer system
Seconds
Limited
The 2nd line of defence against changes in pH is…….acts within….., its efficiency is……, its mechanism is….
Respiratory system
Minutes
Moderate
Contril blood CO2 by adjusting pulmonary ventilation
The 3rd line of defence against changes in pH is…….acts within….., its efficiency is……, its mechanism is….
Kidney mechanism
Hrs to days
Highest most powerful
Controlling blood HCO3- & modify H+ secretion and excreting either alkaline or acidic urine
The main buffer system in ECF is……consists of……
Bicarbonate buffer system
H2CO3/NaHCO3
The major buffer system in ICF is……consists of……
Protein buffer system
Proteinate/proteinic acid
Hemoglobin buffer system consists of……its function is……
Haemoglobinate/acid haemoglobin
Buffers H+ generated from CO2 at tissue level
Phosphate buffer system consists of……its function is……
Monohydrogen phostphaye & dihydrogen phosphate
It is the major buffer im kidney and a major buffer in ICF
What does a change in HCO3-/PCO2 ratio indicate?
When it inc, it is due to either fall in PCO2 or a rise in HCO3-, & vice versa.
pK of bicarbonate buffer is….., while that of phosphate buffer is……
6.1
6.8
GR: Bicarbonate buffer is the most effective buffer in ECF
- Although pK=6.1, which is away from blood pH but H2CO3 & HCO3- are abundant in ECF, so this system is rapidly available to resist changes in pH
- The two components of buffer system are regulated the 1st by respiration the 2nd by kidney
Mention factors affecting effectiveness of a buffer
- pK of buffer, the nearer it is to the pH it has preserve the more effective
- Amount of buffer present: the greater amount the more effective
H+ is not secreted in……
Descending loop of Henle & thin ascending loop of Henle