Which one of the following statements about erythrocytes is false ?

Options

A. In the life cycle of a foetus, erythropoiesis takes place in both liver and bone marrow.
B. They maintain the viscosity of blood.
C. They maintain blood pH as thy contain haemoglobin which acts as a buffer.
D. The total quantity of RBCs in a human male body is around 5.5 million.

Answer

To determine which statement about erythrocytes (red blood cells) is false, we will analyze each provided statement step by step.

### Step 1: Understand the definition of erythrocytes
Erythrocytes, commonly known as red blood cells (RBCs), are responsible for transporting oxygen from the lungs to the rest of the body and returning carbon dioxide from the body back to the lungs.

**Hint:** Remember that erythrocytes are primarily involved in gas exchange in the body.

### Step 2: Evaluate the first statement
The first statement claims that during the life cycle of a fetus, erythropoiesis (the production of RBCs) occurs in both the liver and bone marrow.

- **Analysis:** This statement is true. In fetal development, erythropoiesis starts in the yolk sac, then moves to the liver, and later to the spleen. After birth, it predominantly occurs in the bone marrow.

**Hint:** Consider the stages of fetal development and where blood cell production occurs.

### Step 3: Evaluate the second statement
The second statement asserts that erythrocytes maintain the viscosity of blood.

- **Analysis:** This statement is also true. RBCs are a major component of blood cells, and they contribute to the overall viscosity of blood, which is essential for proper circulation.

**Hint:** Think about the composition of blood and the role of cells versus plasma.

### Step 4: Evaluate the third statement
The third statement states that erythrocytes maintain blood pH because they contain hemoglobin, which acts as a buffer.

- **Analysis:** This statement is true as well. Hemoglobin can bind to hydrogen ions (H+) and helps in maintaining the acid-base balance in the blood.

**Hint:** Recall the role of hemoglobin beyond oxygen transport.

### Step 5: Evaluate the fourth statement
The fourth statement claims that the total quantity of RBCs in a human male body is around 5.5 million.

- **Analysis:** This statement is false. The correct information is that there are approximately 5.5 million RBCs per microliter (µL) of blood, not per body. Given that an average male has about 5 liters of blood, the total number of RBCs would be significantly higher than 5.5 million.

**Hint:** Pay attention to the units used when discussing quantities in biology.

### Conclusion
The false statement about erythrocytes is the fourth one regarding the total quantity of RBCs in a human male body.

### Final Answer
The false statement is: "The total quantity of RBC in a human male body is around 5.5 million."