B3 - The Immune System

What is the main job of the immune system?

To destroy pathogens and any toxins they produce, and to protect the body if the same pathogen invades again.

What happens if the nonspecific defense system fails?

Pathogens can enter the body, multiply, and damage healthy tissue.

What do bacteria release that can make us feel unwell?

Toxins.

What type of cells are involved in the immune system?

White blood cells.

Name the three functions of white blood cells.

Phagocytosis, producing antibodies, and producing antitoxins.

What is phagocytosis?

The process where a white blood cell ingests and destroys a pathogen using enzymes.

What does the word "ingest" mean in biology?

To take in (not eat).

What do white blood cells detect from pathogens?

Chemicals released by the pathogen.

What do white blood cells use to break down pathogens during phagocytosis?

Enzymes.

What are antibodies?

Protein molecules produced by white blood cells that attach to pathogens and trigger their destruction.

How do antibodies work?

They stick to specific pathogens and trigger their destruction.

Why are antibodies described as specific?

Because each type of antibody only works against one type of pathogen.

If a person is infected with measles, what antibodies do they produce?

Antibodies specific to the measles virus.

Can antibodies made for measles protect against other diseases?

No, antibodies are only effective against the pathogen they were made for.

How long can antibodies remain in the blood?

For a long time, which helps protect the person from future infections by the same pathogen.

What is immunity?

When the body can quickly respond to a pathogen it has encountered before, due to memory cells and antibodies remaining in the blood.

What do some bacteria produce that harms the body?

Toxins.

What do white blood cells produce to counteract toxins?

Antitoxins.

How do antitoxins work?

They bind to toxins and neutralise them so they cannot damage cells.

What are antitoxins?

Chemicals made by white blood cells that neutralise toxins produced by pathogens.

Why is the immune system important after a pathogen enters the body?

It helps destroy the pathogen and protects the body from future infections.

Why is the immune system considered specific?

Because it targets specific pathogens with specific antibodies and antitoxins.

What are the two main functions of the immune system?

Destroying pathogens/toxins and providing immunity for future infections.

What is a key difference between the nonspecific defense system and the immune system?

The nonspecific system blocks entry of all pathogens, while the immune system specifically targets and destroys them once inside the body.