Select the one that supports the dissociation of oxyhaemoglobin in tissues .

Options

A. High `pO_2`
B. Low `pO_2`
C. Equal `pO_2`
D. Not dependent on `pO_2`

Answer

To solve the question regarding the dissociation of oxyhemoglobin in tissues, we need to analyze the conditions that influence this process. Here’s a step-by-step breakdown:

### Step 1: Understand the Role of Hemoglobin
- Hemoglobin is a protein in red blood cells responsible for transporting oxygen from the lungs to the tissues and returning carbon dioxide from the tissues back to the lungs.

### Step 2: Define Oxyhemoglobin
- When hemoglobin binds with oxygen, it forms a compound known as oxyhemoglobin. This process is influenced by various factors, including the partial pressure of oxygen (pO2).

### Step 3: Identify Conditions Favoring Oxyhemoglobin Formation
- Oxyhemoglobin formation is favored under certain conditions:
- High partial pressure of oxygen (pO2)
- Low partial pressure of carbon dioxide (pCO2)
- Low concentration of H+ ions (high pH)
- Low temperature

### Step 4: Identify Conditions Favoring Oxyhemoglobin Dissociation
- For oxyhemoglobin to dissociate (release oxygen), the opposite conditions must be present:
- Low partial pressure of oxygen (pO2)
- High partial pressure of carbon dioxide (pCO2)
- High concentration of H+ ions (low pH)
- High temperature

### Step 5: Analyze the Given Options
- The options provided are:
1. High pressure of oxygen
2. Low partial pressure of oxygen
3. Equal partial pressure of oxygen
4. Not dependent on the partial pressure of oxygen

### Step 6: Select the Correct Answer
- Among the options, the condition that supports the dissociation of oxyhemoglobin in tissues is **low partial pressure of oxygen**. This is because tissues typically have a lower pO2 compared to the lungs, facilitating the release of oxygen from hemoglobin.

### Final Answer
- The correct answer is **Option B: Low partial pressure of oxygen**.

---