What is the main function of white blood corpuscles (white blood cells) in the human body?

Introduction / Context:
Blood contains several types of cells with specialized roles. Red blood cells, white blood cells, and platelets all contribute to health in different ways. Understanding the primary function of each cell type is basic but important knowledge in biology and human physiology. This question focuses on the main role of white blood corpuscles, also called white blood cells or leukocytes.

Given Data / Assumptions:

• The question asks for the main function of white blood corpuscles.
• Options include nutrient transport, infection control, oxygen transport, and providing strength.
• We assume awareness of red blood cell and white blood cell functions.

Concept / Approach:
White blood cells are a diverse group that includes neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Their common purpose is to protect the body against infections and foreign substances. They achieve this by phagocytosis, antibody production, cell mediated immunity, and releasing chemical mediators. Red blood cells transport oxygen via hemoglobin, while platelets are involved in clotting. Nutrient transport is mainly carried out by plasma. White blood cells do not primarily carry oxygen or nutrients, and they do not give mechanical strength to blood vessels.

Step-by-Step Solution:
Step 1: Recall that leukocytes are part of the immune system. Step 2: Recognise that neutrophils and macrophages engulf and destroy bacteria and debris. Step 3: Understand that lymphocytes produce antibodies and carry out cell mediated immune responses. Step 4: Note that these functions are all related to combating infection and defending against foreign materials. Step 5: Select the option stating that white blood corpuscles combat infection and defend the body.

Verification / Alternative check:
Immunology and physiology texts define leukocytes as cells involved in protection against infectious disease and foreign invaders. They describe how white blood cells migrate to sites of infection, recognize pathogens, and initiate immune responses. Laboratory tests that measure white blood cell count are commonly used to detect infection or immune system problems, further emphasising their defensive role. These facts confirm that combating infection is the main function of white blood corpuscles.

Why Other Options Are Wrong:

• To carry absorbed nutrients to body tissues: Nutrients are mainly carried dissolved in plasma, not by white blood cells.
• To transport oxygen from lungs to tissues: This is the primary function of red blood cells through hemoglobin.
• To give mechanical strength and rigidity to blood vessels: Blood vessels gain strength from connective tissue and smooth muscle in their walls, not from circulating white blood cells.

Common Pitfalls:
Students may sometimes confuse red and white blood cell roles because both travel in the blood. A simple association is that red blood cells are for respiration and oxygen transport, while white blood cells are for defense and immunity. Another pitfall is to think of plasma as just water, forgetting that it carries nutrients and hormones rather than the cells themselves doing that job. Keeping these distinctions clear helps in answering basic physiology questions rapidly.

Final Answer:
The main purpose of white blood corpuscles is to combat infection and defend the body against foreign organisms.