Energy for ultrafilteration of blood is derived from___________.

Answer

To answer the question "Energy for ultrafiltration of blood is derived from___________," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Ultrafiltration**: Ultrafiltration is a process that occurs in the kidneys, specifically in the nephrons, which are the functional units of the kidney.

2. **Identifying the Structure Involved**: The key structure involved in ultrafiltration is the Bowman's capsule, which is a double-walled cup-like structure that contains a network of capillaries known as the glomerulus.

3. **Process of Ultrafiltration**: In the glomerulus, blood is filtered, and substances such as chloride ions, sodium ions, potassium ions, water, and urea are allowed to pass through, while larger components like blood cells and proteins are retained.

4. **Energy Requirement**: The process of ultrafiltration is described as a passive process. Passive processes do not require energy in the form of ATP because they occur along the concentration gradient (from higher concentration to lower concentration).

5. **Role of Hydrostatic Pressure**: Although ultrafiltration itself is passive, it is driven by hydrostatic pressure. When blood enters the glomerulus through the afferent arteriole, it does so under a hydrostatic pressure of approximately 60 mm Hg. This pressure is crucial as it provides the necessary force for the filtration process to occur.

6. **Conclusion**: Therefore, the energy for ultrafiltration of blood is derived from hydrostatic pressure.

### Final Answer: Hydrostatic pressure.

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