In kidney ultrafiltration occurs due to

Options

A. osmotic concentration
B. glomerular hydrostatic pressure
C. deoxygenated blood
D. exocytosis

Answer

**Step-by-Step Solution:**

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

2. **Identifying the Key Component**: The primary driving force behind ultrafiltration in the kidneys is the glomerular hydrostatic pressure. This pressure is generated by the blood flow into the glomeruli, which are networks of capillaries located in the nephron.

3. **Mechanism of Ultrafiltration**: During ultrafiltration, the high pressure in the glomerular capillaries forces water, ions, and small molecules out of the blood and into the Bowman's capsule, which is the initial part of the nephron.

4. **Outcome of Ultrafiltration**: The substances that are filtered into the Bowman's capsule include water, salts, glucose, and urea, while larger molecules such as proteins and blood cells remain in the bloodstream due to their size.

5. **Conclusion**: Therefore, the ultrafiltration process in the kidneys occurs due to glomerular hydrostatic pressure, which is also referred to as glomerular filtration.

**Final Answer**: Ultrafiltration in the kidney occurs due to glomerular hydrostatic pressure.

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