Q.The cells involved in inflammatory reactions are
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Types of Leucocytes (White Blood Cells)
Imagine your blood as a busy city. Red blood cells are the delivery trucks, carrying oxygen. Platelets are the road repair crews, patching up leaks. But the white blood cells — the leucocytes — are the police and army. Their only job is to find, fight, and destroy anything that doesn't belong: bacteria, viruses, parasites, even your own cells if they turn cancerous.
There are about 4,000 to 11,000 white blood cells in every microliter of your blood. But they are not all the same. They come in two broad families, and the difference is visible under a microscope.
The Two Families: Granulocytes vs Agranulocytes
The name tells you the story. Granulocytes have visible little sacs (granules) inside their cytoplasm when you stain them. These granules are like ammunition pouches — they contain enzymes and chemicals to kill invaders. Agranulocytes look smooth inside; they have no such visible granules. Their weapons are different.
The "granules" in granulocytes are not just decoration. They are lysosomes and secretory vesicles packed with digestive enzymes, histamine, and other attack chemicals.
Granulocytes (The "Granular" Fighters)
These cells have a nucleus that is lobed — it looks like it has 2–5 separate blobs connected by thin threads. They are also called polymorphonuclear leukocytes (many-shaped nucleus). There are three types, and they are distinguished by how their granules take up dye.
1. Neutrophils (The Frontline Soldiers)
Intuition: If a bacterial infection starts, neutrophils are the first responders. They rush to the site, swallow bacteria whole (phagocytosis), and then die. Pus is mostly dead neutrophils.
Precise statement: Neutrophils make up 60–70% of all white blood cells. Their granules stain with both acidic and basic dyes, appearing a pale pink or lilac. They have a nucleus with 3–5 lobes. They are the most abundant and the fastest to arrive at an infection.
A high neutrophil count usually means a bacterial infection. A low count (neutropenia) makes you very vulnerable to infection.
2. Eosinophils (The Parasite Hunters & Allergy Responders)
Intuition: Think of a tapeworm or a hookworm — too big for a neutrophil to swallow. Eosinophils attach to the parasite's surface and release their granules to kill it. They also show up in allergic reactions.
Precise statement: Eosinophils make up only 2–4% of WBCs. Their granules stain bright red-orange with acidic dyes like eosin. The nucleus is typically bilobed (two lobes, like a pair of glasses). They are especially active against parasitic worms and modulate allergic inflammation.
3. Basophils (The Alarm System)
Intuition: Basophils are rare. When they encounter an allergen, they explode, releasing histamine and heparin. Histamine causes inflammation and itching; heparin prevents blood clotting at the site. They are the "fire alarm" that calls other immune cells to the area.
Precise statement: Basophils are the least common granulocyte, less than 1% of WBCs. Their large granules stain dark blue-purple with basic dyes, often obscuring the nucleus. They release histamine (vasodilation, inflammation) and heparin (anticoagulant). They are central to immediate hypersensitivity (allergic) reactions.
Granulocyte Summary
| Type | % of WBCs | Granule Color | Nucleus Shape | Main Role |
|---|---|---|---|---|
| Neutrophil | 60–70% | Pale pink/lilac | 3–5 lobes | Phagocytosis of bacteria |
| Eosinophil | 2–4% | Bright red-orange | Bilobed | Kill parasites, allergy |
| Basophil | <1% | Dark blue-purple | Often hidden | Release histamine, heparin |
Agranulocytes (The "Smooth" Fighters)
These cells have no visible granules in the cytoplasm. Their nucleus is not lobed — it is round, kidney-shaped, or indented. They are also called mononuclear leukocytes (single nucleus).
1. Lymphocytes (The Special Forces & Memory)
Intuition: Lymphocytes are not just soldiers; they are also intelligence officers. They learn to recognise a specific invader, then either kill it directly or produce antibodies that tag it for destruction. And they remember it for years — that is why you only get chickenpox once.
Precise statement: Lymphocytes make up 20–30% of WBCs. They have a large, round nucleus that fills most of the cell, with only a thin rim of pale blue cytoplasm. There are two main types:
- B lymphocytes (B cells): Produce antibodies (humoral immunity).
- T lymphocytes (T cells): Kill infected cells directly (cell-mediated immunity). …
Basophils are the white blood cells involved in inflammatory reactions. They secrete substances such as histamine, serotonin and heparin, which are the mediators that drive an inflammatory response, distinguishing basophils from the phagocytic neutrophils, the infection-resisting eosinophils, and …
Basophils are the white blood cells specialised for inflammatory reactions, secreting mediators such as histamine, serotonin and heparin.
Among the granulocyte white blood cells, basophils are the least common, making up only about 0.5 to 1 per cent of the total, but they have a distinctive role: they secrete substances such as histamine, serotonin and heparin, and take part in inflammatory reactions. …
Method: Matching a Cell to Its Single Defining Secreted Product or Role
Use this approach whenever a question links a cell type to a specific physiological process through what it releases.
Steps
Step 1: List what each option is chiefly known for
Basophils → histamine, serotonin, heparin; neutrophils → phagocytosis; eosinophils → resisting infection and allergic reactions; lymphocytes → the broader immune response.
Step 2: Match the process named in the question to the specific mediators associated with it
Inflammation is classically driven by histamine — recall which cell secretes it, rather than which cell is broadly "involved in defence."
Step 3: Confirm the option whose secretions literally drive the named process …
- TG EAPCET 2022Set ap-2022-07-31-FN1 markMCQQ.Match the following : Leucocyte Number A) Eosinophils I) 5.3 % B) Monocytes II) 30% C) Basophils III) 2.3% D) Lymphocytes IV) 62% V) 0.4% The correct match is (A) A B C D III I IV II (B) A B C D II V III I (C) A B C D IV I III III (D) A B C D III I V II
›Reveal solutionSolution
This question tests the typical differential leukocyte count (DLC) percentages in human blood. The correct match is A–III, B–I, C–V, D–II, which corresponds to option (D).
The concept here is the differential white blood cell count — the relative percentages of each type of leukocyte in normal adult blood. These values are standard in physiology and are often memorized, but understanding the relative abundance helps avoid confusion. Eosinophils and basophils are rare, monocytes are intermediate, and lymphocytes are the second most abundant after neutrophils (which are not listed here). The trick is to pair the rarest cells with the smallest percentages.
Let’s match step by step:
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Eosinophils (A) — These are moderately rare, typically around 2–4%. The closest value in the list is 2.3% (III). So A → III.
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Monocytes (B) — They make up about 3–8% of leukocytes. The value 5.3% (I) fits perfectly. So B → I.
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Basophils (C) — These are the rarest white blood cells, usually less than 1%. The only value that small is 0.4% (V). So C → V.
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Lymphocytes (D) — They are the second most common, normally 20–40%. The largest remaining percentage is 30% (II). So D → II.
Now check the options:
- (A) A–III, B–I, C–IV, D–II → C is wrong (IV is 62%, far too high).
- (B) A–II, B–V, C–III, D–I → all mismatched.
- (C) A–IV, B–I, C–III, D–III → repeats III and uses IV incorrectly. …
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- TG EAPCET 2021Set ap-2021-08-10-AN1 markMCQQ.Pick up the mismatched pair (A) Basophils - 6% (B) Esinophils - 2.3% (C) Neutrophils - 62% (D) Monocytes - 5.3%
›Reveal solutionSolution
This question tests knowledge of the normal percentage distribution of different types of white blood cells (leukocytes) in human blood. The pair with Basophils at 6% is mismatched because their normal percentage is much lower.
Concept and Intuition
White blood cells, also known as leukocytes, are crucial components of the immune system, defending the body against infections and foreign substances. There are five main types of leukocytes, each with specific roles: Neutrophils, Lymphocytes, Monocytes, Eosinophils, and Basophils.
The relative proportion of these different types of white blood cells in the blood is typically stable in a healthy individual. This distribution is often referred to as a "differential leukocyte count." Deviations from these normal percentages can indicate various physiological conditions, infections, or diseases. For example, an increase in neutrophils might suggest a bacterial infection, while an increase in eosinophils could point to an allergic reaction or parasitic infection. Therefore, knowing the normal ranges is fundamental for diagnostic purposes.
The question asks to identify the mismatched pair, meaning one of the options presents a percentage that is significantly outside the normal, healthy range for that specific type of white blood cell.
Step-by-Step Solution
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Recall the normal percentage ranges for each type of leukocyte:
The typical normal percentage ranges for the five types of white blood cells in human blood are:
- Neutrophils: 60−65%
- Lymphocytes: 20−25%
- Monocytes: 6−8%
- Eosinophils: 2−3%
- Basophils: 0.5−1%
ImportantThese percentages represent the relative abundance of each leukocyte type among all white blood cells.
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Evaluate each given option against its normal range:
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(A) Basophils - 6%
The normal range for Basophils is 0.5−1%. A value of 6% is significantly higher than this normal range. Basophils are the least numerous type of white blood cell. This pair is a clear mismatch.
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(B) Eosinophils - 2.3%
The normal range for Eosinophils is 2−3%. The value 2.3% falls within this normal range. This pair is correctly matched. …
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- TG EAPCET 2021Set ap-2021-08-10-FN1 markMCQQ.Pick up the mismatched pair (A) Basophils − 6% (B) Esinophils − 2.3% (C) Neutrophils − 62% (D) Monocytes − 5.3%
›Reveal solutionSolution
The question tests the normal differential leukocyte count (DLC) percentages. The mismatched pair is (B) Eosinophils – 2.3%, because the normal eosinophil range is 1–4%, and 2.3% falls within it — but the actual mismatch is that the given value is too low for eosinophils? Wait, let’s check: the correct normal values are: Neutrophils 40–80% (typically 60–70%), Eosinophils 1–4%, Basophils 0.5–1%, Monocytes 2–8%. Here, Basophils at 6% is far too high (normal ~0.5–1%), so (A) is the mismatched pair.
The key concept here is the differential leukocyte count (DLC) — the percentage distribution of different white blood cells in a blood smear. In Indian medical entrance exams (NEET, AIIMS, etc.), you are expected to memorize the approximate normal ranges for each type of WBC. The question gives four pairs: cell type and a percentage. One of these percentages does not match the normal range for that cell type. Your job is to spot the odd one out.
Let’s recall the standard normal ranges (as commonly taught):
WBC type Normal percentage range Neutrophils 40–80% (often quoted as 60–70%) Eosinophils 1–4% Basophils 0.5–1% (sometimes up to 2%) Monocytes 2–8% Lymphocytes 20–40% Now examine each option:
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Option (A): Basophils – 6%
Basophils are the rarest granulocytes. Their normal count is typically 0.5–1% of total WBCs. Even in some textbooks, the upper limit is 2%. A value of 6% is far outside this range — it would indicate a pathological condition (e.g., basophilic leukemia or chronic myeloid leukemia). So this is clearly mismatched.
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Option (B): Eosinophils – 2.3% …
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