Immune System - Free Printable

Task: Match the description with the correct term.

Here is the solution to the matching exercise, along with explanations for each answer:

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#### 1. Occurs when the immune system attacks a body’s healthy cells
- Answer: D (Autoimmune disease)
- Explanation: Autoimmune diseases occur when the immune system mistakenly attacks the body's own healthy cells, tissues, or organs.

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#### 2. The largest blood cells of the immune system living throughout the body
- Answer: M (Macrophages)
- Explanation: Macrophages are large white blood cells that play a crucial role in the immune system by engulfing and destroying pathogens and debris.

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#### 3. In charge of keeping the body safe from invading germs
- Answer: H (Immune system)
- Explanation: The immune system is responsible for defending the body against infections caused by pathogens such as bacteria, viruses, and fungi.

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#### 4. The first defense against germs entering the body
- Answer: P (Skin)
- Explanation: The skin acts as a physical barrier, preventing most pathogens from entering the body. It is the first line of defense in the immune system.

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#### 5. Proteins produced by the body to fight germs
- Answer: B (Antibodies)
- Explanation: Antibodies are proteins produced by B-cells in response to antigens (foreign substances). They help neutralize pathogens and mark them for destruction.

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#### 6. Moves in the blood seeking germs and bacteria that don’t belong
- Answer: O (Neutrophils)
- Explanation: Neutrophils are a type of white blood cell that circulates in the bloodstream and quickly moves to sites of infection to engulf and destroy pathogens.

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#### 7. Destroys infected cells
- Answer: I (Killer T-cells)
- Explanation: Killer T-cells (also called cytotoxic T-cells) identify and destroy infected cells, such as those infected by viruses.

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#### 8. Tells B-cells to start making antibodies and gives instructions to T-cells
- Answer: G (Helper T-cells)
- Explanation: Helper T-cells coordinate the immune response by activating B-cells to produce antibodies and directing killer T-cells to attack infected cells.

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#### 9. White blood cells that attack infections of the body
- Answer: L (Lymphocytes)
- Explanation: Lymphocytes are a type of white blood cell that includes B-cells, T-cells, and natural killer cells, all of which play key roles in fighting infections.

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#### 10. Another term for germs; the invaders of the body
- Answer: C (Antigen)
- Explanation: Antigens are foreign substances, such as bacteria, viruses, or toxins, that trigger an immune response in the body.

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#### 11. Remember the germs that previously attacked the body
- Answer: N (Memory cells)
- Explanation: Memory cells (both B-memory cells and T-memory cells) retain information about past infections, allowing the immune system to respond more quickly and effectively if the same pathogen re-infects the body.

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#### 12. Glands that collect and destroy bacteria/viruses before they travel through the body
- Answer: K (Lymph system)
- Explanation: The lymph system includes lymph nodes, which filter lymph fluid and trap pathogens, helping to prevent their spread throughout the body.

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#### 13. Controls the flow of blood throughout the body
- Answer: F (Circulatory system)
- Explanation: The circulatory system, consisting of the heart, blood vessels, and blood, transports nutrients, oxygen, and immune cells throughout the body.

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#### 14. Finds hidden germs or unhealthy cells and destroys them
- Answer: J (Killer T-cells)
- Explanation: Killer T-cells detect and eliminate infected or abnormal cells, such as cancer cells or cells infected by viruses.

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#### 15. Occurs when the immune system attacks too often, even against safe food products
- Answer: A (Allergies)
- Explanation: Allergies occur when the immune system overreacts to harmless substances, such as pollen, dust, or certain foods, treating them as threats.

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#### 16. A weak virus that is injected into the body
- Answer: R (Vaccine)
- Explanation: Vaccines contain weakened or inactivated versions of pathogens (or parts of them) that stimulate the immune system to develop immunity without causing disease.

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#### 17. Place where lymph fluid travels to different parts of the body
- Answer: K (Lymph system)
- Explanation: The lymph system is a network of vessels and nodes that transport lymph fluid, which contains immune cells and helps defend against infections.

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#### 18. Produces antibodies and are used for specific germs
- Answer: B (Antibodies)
- Explanation: Antibodies are produced by B-cells and are highly specific to particular antigens, helping to neutralize or tag pathogens for destruction.

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Using your own words, describe how a vaccine works:

A vaccine works by introducing a harmless version of a pathogen (such as a weakened virus or a piece of it) into the body. This stimulates the immune system to recognize the pathogen as foreign and mount a response, including producing antibodies and memory cells. When the actual pathogen later infects the body, the immune system can quickly recognize it and launch a rapid, effective defense, preventing illness or reducing its severity.

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Final Answer:

\[
\boxed{
\begin{array}{ll}
1. & \text{D (Autoimmune disease)} \\
2. & \text{M (Macrophages)} \\
3. & \text{H (Immune system)} \\
4. & \text{P (Skin)} \\
5. & \text{B (Antibodies)} \\
6. & \text{O (Neutrophils)} \\
7. & \text{I (Killer T-cells)} \\
8. & \text{G (Helper T-cells)} \\
9. & \text{L (Lymphocytes)} \\
10. & \text{C (Antigen)} \\
11. & \text{N (Memory cells)} \\
12. & \text{K (Lymph system)} \\
13. & \text{F (Circulatory system)} \\
14. & \text{J (Killer T-cells)} \\
15. & \text{A (Allergies)} \\
16. & \text{R (Vaccine)} \\
17. & \text{K (Lymph system)} \\
18. & \text{B (Antibodies)}
\end{array}
}
\]