Which among the following is referred to as alkali reserve of the body?
**Core Concept**
The alkali reserve of the body refers to the amount of bicarbonate ions (HCO3-) present in the blood, which plays a crucial role in maintaining acid-base balance. The bicarbonate buffer system helps to regulate pH by neutralizing excess hydrogen ions.
**Why the Correct Answer is Right**
The bicarbonate buffer system consists of bicarbonate ions (HCO3-) and carbonic acid (H2CO3). When hydrogen ions accumulate in the blood, they react with bicarbonate ions to form carbonic acid, which then dissociates into water and carbon dioxide. This process helps to maintain the acid-base balance in the body. The bicarbonate ions are generated in the liver from carbon dioxide and water through the enzyme carbonic anhydrase.
**Why Each Wrong Option is Incorrect**
**Option A:** Lactate is a byproduct of anaerobic metabolism and is not directly related to the alkali reserve of the body.
**Option B:** Chloride ions (Cl-) are an essential component of various bodily fluids, but they do not contribute to the alkali reserve.
**Option C:** Phosphate ions (PO4-) play a crucial role in various metabolic processes, but they are not directly involved in maintaining acid-base balance.
**Clinical Pearl / High-Yield Fact**
The bicarbonate buffer system is essential for maintaining acid-base balance in the body. A decrease in bicarbonate levels can lead to metabolic acidosis, while an increase can lead to metabolic alkalosis.
**Correct Answer:** C. Bicarbonate ions (HCO3-) are referred to as the alkali reserve of the body.