How Kidney maintain blood pH?

Answer 1

The kidneys place a role in determining the body's ACID-BASE balance - that is, they help to ensure that the pH of the blood does not fall below or rise above 7.3.

There are two possible routes by which pH can change:

RESPIRATORY CAUSES

* Respiratory Acidosis results from a HIGH blood gas concentration of CO2 which becomes carbonic acid when dissolved in water. This usually occurs because the patient just isn't breathing effectively enough - such as in morphine overdose where the automatic control of ventilation is suppressed. The body must compensate for this dangerous decrease in pH (to put things into perspective, a pH of 6.8 will mean life is NOT sustainable) and in the case of RESPIRATORY ACIDOSIS, it employs a RENAL compensation. If the normal buffering systems in the blood are overwhelmed (haemoglobin, bicarbonate, phospate and plasma proteins all usually help to mop up excess acid) then the kidney excretes more acid, and reabsorbs more bicarbonate. This INCREASES the buffering capacity of the blood, and reduces the acid content.

* Respiratory Alkalosis results from a LOW blood gas concentration of CO2. This can occur during HYPERVENTILATION (e.g. during a panic attack, or during the early stages of an Asthma attack). The lungs are 'blowing off' higher levels of carbon dioxide than necessary, and this pulls the pH up. The kidney also plays a role here, by doing the opposite: it DECREASES excretion of acid, and reabsorbs less bicarbonate, so DECREASING the buffering capacity of the blood, and increasing the acid content. This serves to pull the pH back down to normal levels.

Renal compensation takes a long time to kick in - up to 5 days - but is effective.

METABOLIC CAUSES

* Metabolic Acidosis is caused by an increased production of acid or a decreased availability of bicarbonate (HCO3). Lots of different things can cause a metabolic acidosis. These depend on the ANION GAP (i.e. the ratio of positively charged ions to negatively charged ones). Acidosis with a normal anion gap can be due to longstanding diarrohoea, or glue sniffing. An increased anion gap in acidosis can be an indication of lactic acidosis or diabetic ketoacidosis. The compensation for these is via the RESPIRATORY system. Chemoreceptors around the body detect the fall in pH and INCREASE the breathing rate - effectively causing hyperventilation. This makes us blow off more carbon dioxide, and thus decreases the acid content of the blood.

* Metabolic Alkalosis is caused by a decreased production of acid, or an increased availability of HCO3. Vommitting can cause this, where acidic H+ ions are lost. Anything which causes HYPOKALAEMIA (i.e. a low level of potassium) can also cause this. This happens because, in the kidney, hydrogen and potassium ions are exchanged. Less available potassium, means less hydrogen can be absorbed, and so the pH increases. The body reacts to this with RESPIRATORY compensation - we decrease our breathing. This increases the CO2 content of the blood are decreases the pH back towards the normal value.

Respiratory compensation happens very rapidly, but is much less effective at maintaining pH.

Answer 2

H+ ions are pulled out of the blood stream by the kidney's proximal convoluted tubules of the medulla and cortex, thus regulating the bodies overall PH. (Northern Illinois University - Medical Laboratory Student).

Answer 3

The kidneys help regulate the body's PH by excreting hydrogen ions. The kidneys play a big role in regulating the body's blood plasma's PH balance.

Answer 4

The kidneys control pH by adjusting the amount of HCO3 − that is reabsorbed and the amount of H+ that is excreted; increase in HCO3 − is equivalent to removing free H+.

Answer 5

By removing toxins and excess water

Answer 6

i believe it filters the blood

Answer 7

Yes :)