Learn about the functions of white blood cells (WBCs) in fighting infections, producing antibodies, and protecting against diseases. Discover their vital role in immunity!
Functions of White Blood Cells (WBCs) in the Human Body
Definition of White Blood Cells
White blood cells (WBCs), also called leukocytes, are a crucial part of the immune system. They help the body fight infections, destroy harmful substances, and protect against diseases. Unlike red blood cells, WBCs have a nucleus and can move freely through blood and tissues to combat invaders like bacteria, viruses, fungi, and parasites.
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Functions of White Blood Cells
1. Fighting Infections
- WBCs identify and attack bacteria, viruses, fungi, and parasites to prevent infections.
- They release enzymes and chemicals that neutralize harmful microbes.
2. Producing Antibodies
- Lymphocytes (B-cells) create antibodies that recognize and destroy specific pathogens.
- This helps the body develop long-term immunity (e.g., after vaccination).
3. Destroying Harmful Substances (Phagocytosis)
- Neutrophils and macrophages engulf and digest harmful bacteria, dead cells, and foreign particles.
- This process, called phagocytosis, helps keep the body clean and free from infections.
4. Inflammation and Wound Healing
- Basophils and mast cells release histamine, which causes inflammation to increase blood flow to the affected area.
- This speeds up wound healing and prevents further infection.
5. Killing Cancerous and Abnormal Cells
- Natural killer (NK) cells and T-cells detect and destroy cancerous, infected, or damaged cells.
- This function helps protect against tumor growth and autoimmune diseases.
6. Regulating the Immune Response
- Helper T-cells activate and coordinate other immune cells.
- Suppressor T-cells regulate immune activity to prevent overreaction and reduce autoimmune diseases.
7. Memory for Future Immunity
- Memory B-cells and T-cells store information about past infections.
- This allows the immune system to respond faster and stronger to the same pathogen in the future.
Types of White Blood Cells and Their Functions
| Type of WBC | Function |
|---|---|
| Neutrophils | First responders that engulf and destroy bacteria. |
| Lymphocytes (B-cells & T-cells) | Produce antibodies, kill infected cells, and provide immunity. |
| Monocytes (Macrophages) | Engulf and digest pathogens and dead cells. |
| Eosinophils | Fight parasites and are involved in allergic reactions. |
| Basophils | Release histamine and promote inflammation. |
Revision Questions and Answers
1. What are white blood cells, and what is their main function?
Answer: White blood cells (WBCs), or leukocytes, are immune cells that protect the body from infections, foreign invaders, and diseases.
2. How do white blood cells fight infections?
Answer: WBCs fight infections by engulfing and digesting harmful microbes (phagocytosis), producing antibodies, and releasing chemicals that kill pathogens.
3. What are the different types of white blood cells and their functions?
Answer:
- Neutrophils – First responders that engulf and destroy bacteria.
- Lymphocytes (B-cells & T-cells) – Produce antibodies and kill infected cells.
- Monocytes (Macrophages) – Engulf and digest pathogens and dead cells.
- Eosinophils – Fight parasites and are involved in allergic reactions.
- Basophils – Release histamine and promote inflammation.
4. How do lymphocytes help in immunity?
Answer: B-cells produce antibodies that attack pathogens, while T-cells destroy infected or cancerous cells and regulate immune responses.
5. What role do white blood cells play in wound healing?
Answer: WBCs help heal wounds by fighting infections, reducing inflammation, and removing dead cells, allowing new tissue to form.
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Conclusion on the Functions of White Blood Cells
White blood cells are the body’s defense system, protecting against infections, diseases, and harmful substances. They fight infections, produce antibodies, regulate immune responses, and help heal wounds. A healthy immune system depends on WBCs to maintain overall health and immunity.