Question

The diagram shows a motor (effector) neuron. Which structure is also found in white blood cells, but not in red blood cells?

Answer 1

Hint: To solve this question, first try to recognize what A, B, C and D is. Then try to understand which of these can be present in blood cells.

Complete answer:

Fig: Structure of a typical neuron

Now, from the above diagram we will try to solve the given question. From the given question, we will first identify A, B, C and D.
1. A is the cell body of the neuron.
2. B is the dendrite of a neuron.
3. C is the myelin sheath of axon.
4. D is the nucleus of a neuron.
Now we have knowledge about the presence of nucleus on blood cells.
1. White blood cells have nucleus.
2. Red blood cells do not have nuclei.
3. Platelets also do not have nuclei.

    Fig: RBC (Red Blood Cells) Fig: WBC (White Blood Cells)
From the above diagrams, we can clearly see nucleus is present on WBCs, but RBCs do not have nucleus.

So, the final answer will be the nucleus, which is present in neurons, can also be found in white blood cells but not in red blood cells.

Additional information:WBCs are of two types: Granulocytes and Agranulocytes.
These Granulocytes and Agranulocytes again sub-divided into many cells- neutrophil, eosinophil and basophil are under granulocytes; lymphocytes and monocytes are under agranulocytes.
Both of these have nuclei.
The appearance of the nucleus is different in these types of WBCs.
When you prepare blood film, you are able to see the different types of WBCs with its nucleus in the WBCs.

Note:Carefully remember the presence of nucleus in the blood cells in case of humans as well as some common animals eg, camel, frog, monkey etc. Also remember the functions of WBCs like it plays an important role in the immune system.
The WBCs fight with the foreign particles that enter our body and defend our body from getting infected. The source of WBCs are bone marrow.