Science Year 9 Semester 1 - Immune Response

What is the immune system?

The body system that prevents and fights disease, made up of many organs, tissues, and cells working together

What is a pathogen?

A microscopic organism or agent the causes disease

What is the first line of defence?

A system of barriers to prevent pathogens from entering the body

What are some components of the first line of defence?

Skin, Tears, Saliva, Mucus, Stomach Acid, Cilia, Urine Flow

What is the difference between chemical barriers and physical barriers?

Physical Barriers stop pathogens from entering the body by blocking or trapping them.

Chemical Barriers stop pathogens from entering the body by killing them before they can enter the body.

What are some examples of chemical and physical barriers, and are there any that satisfy both?

Physical: Skin, Cilia

Chemical: Urine, Stomach Acid

Both: Tears, Saliva, Mucus

What is the second line of defence?

General responses from the body that treats all pathogens the same.

An infection occurs when a pathogen gets past the first line of defence and makes it into the body.

What are some things the second line of defence does?

Fever, Inflammation, Phagocytes

What are phagocytes?

A type of white blood cell that destroys any foreign cells by engulfing it, essentially eating and digesting the pathogen

What is the purpose of a fever?

During an infection, your body increases your core body temperature. This helps slow down the pathogens or kill them entirely. Once the infection is taken care of, the core temperature returns to normal.

Fill in the blanks (not every term will be used)

What is the third line of defence?

The body’s third way of fighting disease. It targets specific pathogens and builds long term immunity against it in case that same pathogen returns

What is third line of defence made of?

Specialized white blood cells that target specific pathogens

What is an antigen?

A foreign substance that enters your body

What is an antibody?

A protein produced by your immune system to attack and fight off these antigens

Match the terms to the pictures.

A1
B5
C4
D3
E2

What is a simple definition of bias?

Bias is favouring or opposing something unfairly, often without considering it openly or equally.