value of `pO_2` in deoxygenated blood is equal to value of `pCo_2` in
1) systemic veins
2) systemic arteries
3) pulmonary arteries
4) atmosphere

Options

A. systemic veins
B. systemic arteries
C. pulmonary arteries
D. atmosphere

Answer

To solve the question regarding the value of `pO2` in deoxygenated blood being equal to the value of `pCO2`, we will follow these steps:

### Step 1: Understand the Values of pO2 and pCO2
- In deoxygenated blood, the approximate value of `pO2` is around 40 mmHg. This is the partial pressure of oxygen in the blood that has returned to the heart from the body tissues.
- In contrast, the partial pressure of carbon dioxide (`pCO2`) in deoxygenated blood is higher, around 45 mmHg, as it is a waste product from cellular respiration.

### Step 2: Analyze the Options
1. **Systemic Veins**: These carry deoxygenated blood, so they would have a low `pO2` (around 40 mmHg) and a higher `pCO2` (around 45 mmHg).
2. **Systemic Arteries**: These carry oxygenated blood, which means they would have a high `pO2` (around 95-100 mmHg) and a low `pCO2` (around 40 mmHg).
3. **Pulmonary Arteries**: These also carry deoxygenated blood from the heart to the lungs, so they would have a low `pO2` (around 40 mmHg) and a higher `pCO2`.
4. **Atmosphere**: The atmospheric pressure of `pCO2` is significantly lower than that of deoxygenated blood.

### Step 3: Identify the Correct Answer
- We need to find a vessel where the `pCO2` is equal to the `pO2` of deoxygenated blood (40 mmHg).
- The only option that has a `pCO2` of approximately 40 mmHg is the **Systemic Arteries**, which carry oxygenated blood.

### Conclusion
Thus, the correct answer is **Systemic Arteries**.

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