The partial pressure of oxygen at ((A)) and blood capillary of lungs ((B)) will be :

Options

A. A : 104 mm Hg , B : 95 mm Hg
B. A : 159 mm Hg , B : 95 mm Hg
C. A : 104 mm Hg , B : 40 mm Hg
D. A : 159 mm Hg , B : 95 mm Hg

Answer

To solve the question regarding the partial pressure of oxygen at point A (presumably the alveoli) and in the blood capillaries of the lungs, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Partial Pressure of Oxygen**:
- The partial pressure of oxygen (pO2) refers to the pressure exerted by oxygen in a mixture of gases. It is a measure of how much oxygen is available to be utilized by the body.

2. **Partial Pressure in the Alveoli (Point A)**:
- In the alveoli of the lungs, the partial pressure of oxygen is typically around 104 mm Hg. This is the pressure exerted by oxygen in the alveolar air, which is crucial for gas exchange.

3. **Partial Pressure in Blood Capillaries (Point B)**:
- As blood flows through the pulmonary capillaries, it encounters a narrower space, which can affect the pressure. The partial pressure of oxygen in the blood capillaries of the lungs is approximately 95 mm Hg. This slight decrease occurs due to the dynamics of blood flow and gas exchange.

4. **Conclusion**:
- Therefore, the partial pressures of oxygen are:
- At point A (Alveoli): 104 mm Hg
- At point B (Blood capillaries of lungs): 95 mm Hg

### Final Answer:
- The partial pressure of oxygen at point A is **104 mm Hg**, and at point B (blood capillaries of lungs) is **95 mm Hg**.

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