Which process plays important role in maintenance of ionic and acid base balance of body fluids

Options

A. ultrafiltration
B. tubular secretion
C. reabsorption
D. glomerular filtration

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which process is crucial for maintaining the ionic and acid-base balance of body fluids. This involves understanding the functions of various processes involved in urine formation.

2. **Identifying the Processes**: The options provided are:
- Option 1: Ultrafiltration
- Option 2: Tubular secretion
- Option 3: Reabsorption
- Option 4: Glomerular filtration

3. **Analyzing Each Process**:
- **Ultrafiltration**: This is the initial process in the kidneys where blood is filtered in the glomerulus, but it does not directly regulate ionic or acid-base balance.
- **Tubular Secretion**: This process involves the active transport of substances from the blood into the renal tubules. It plays a significant role in removing excess ions (like H+ and K+) and waste products, thereby helping to maintain pH and ionic balance.
- **Reabsorption**: This process involves the reabsorption of essential ions and water back into the bloodstream, but it is more about conserving substances rather than directly regulating balance.
- **Glomerular Filtration**: Similar to ultrafiltration, this is the first step in urine formation and does not specifically regulate ionic or acid-base balance.

4. **Conclusion**: Based on the analysis, tubular secretion is the process that actively regulates the ionic and acid-base balance by secreting H+, K+, and other substances in the proximal convoluted tubule (PCT), distal convoluted tubule (DCT), and collecting duct.

5. **Final Answer**: The process that plays an important role in the maintenance of ionic and acid-base balance of body fluids is **Option 2: Tubular secretion**.