By which mechanism, oxygen is released out from lungs to cells

Options

A. Diffusion
B. Facilitated diffusion
C. Transpiration
D. Osmosis

Answer

**Step-by-Step Solution:**

1. **Understanding the Context**: The question asks about the mechanism by which oxygen is released from the lungs to the cells. This involves understanding the process of gas exchange in the body.

2. **Identifying Key Components**: In the lungs, oxygen is taken up by red blood cells (RBCs) and transported throughout the body. Cells utilize oxygen for metabolic processes, particularly in aerobic respiration.

3. **Metabolism in Cells**: Inside the cells, oxygen is consumed during aerobic respiration, leading to the production of energy. This process also produces carbon dioxide as a byproduct.

4. **Pressure Gradients**: As cells use oxygen, the partial pressure of oxygen decreases within the cell, while the partial pressure of carbon dioxide increases due to metabolic activity. This creates a concentration gradient.

5. **Diffusion Process**: Gases move from areas of high pressure to areas of low pressure. In this case, oxygen moves from the RBCs (where the partial pressure of oxygen is high) into the cells (where the partial pressure of oxygen is low). Conversely, carbon dioxide moves from the cells (high concentration) into the blood (low concentration).

6. **Conclusion**: The mechanism by which oxygen is released from the lungs to the cells is called **diffusion**. This process does not require energy and occurs spontaneously due to the concentration gradients of the gases involved.

**Final Answer**: The mechanism by which oxygen is released from the lungs to the cells is **diffusion**.

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