Acid Base Balance
How urine is acidified.
Urinary mechanism - kidneys regulate the blood pH here. Urine is acidified when distal tubules secrete hydrogen into urine from the blood, in exchange for sodium bicarbonate.
What is pH and acid base balance. What is normal pH range of blood, arterial blood and venous blood.
pH - indicates hydrogen ion concentration of a fluid. 7 is neutral. Higher than 7 is basic (alkaline) lower than 7 is acidic. Normal range is 7.35 - 7.45 Arterial blood is usually 7.45 Venous blood is usually 7.35
compensatory mechanisms that helps return blood pH to near normal levels during imbalances.
Buffers - substances that help prevent change in pH of fluid, providing balance. "Fixed" acids are buffered by sodium bicarbonate and carbonic acid. Usually more acids than bases are added to body fluids, and they are then weakened when they enter blood by the buffer salts Chemical pH control mechanism is when buffers in bloods and fluids change the pH Physiological pH control mechanism is when pH is changed by respiratory rate, changes in blood in CO2 or changed by altered renal activity. Buffer pairs consist of sodium bicarbonate and carbonic acid. Carbonic acid in blood increases slightly, while the amount of bicarbonate decreases,
Metabolic and respiratory imbalances and disturbances
Metabolic disturbance affects the sodium bicarbonate levels of blood. Metabolic acidosis - deficit (diabetes, diarreha, ingest toxins) and alkalosis is excess (vomiting, diuretic therapy) Respiratory disturbances affect the carbonic acid levels in blood,
Respiratory vs urinary mechanisms of pH control
Respirations remove CO2 from the blood as it flows through the lung capillaries. The sodium bicarbonate amount is decreased therefore so is the hydrogen ion concentration and the pH. Respiratory controls also react to dropping pH through increase of respirations, and decrease of respirations to increase of pH. Holding one's breath leads to increase of CO2 and drop in pH, forcing you to inhale as a surviving mechanism. Acidosis results from anything that causes decreased respirations over time. Alkalosis - increase in respirations.
