Lesson 5: Human defence systems

Question 1

What is the job of the non- specific defense system?

Answer 1

• The job of the non- specific defense system is to prevent pathogens from entering the body.

Question 2

How does the skin prevent pathogens entering the body?

Answer 2

• Acts as protective layer.
• Dead cells on surface of skin are hard to penetrate by pathogens.
• Skin produced sebum which can kill bacteria.
• Skin scabs over when there is a cut to avoid pathogens entering the body.

Question 3

Give the 4 areas of the body where there are non- specific defense systems.

Answer 3

• Skin
• Nose
• Trachea and bronchi
• Stomach

Question 4

How does the nose prevent pathogens entering the body?

Answer 4

• Nose contains hair and mucus that trap pathogen before entering the breathing system.

Question 5

How do the trachea and bronchi prevent pathogens entering our lungs?

Answer 5

• Covered in cilia.
• Cilia are covered in mucus which trap the pathogens.
• CIlia wafts up the mucus to the throat where it is swallowed into the stomach.

Question 6

How does the stomach prevent pathogens entering our digestive system?

Answer 6

• Hydrochloric acid kills pathogens before they can make their way down further into the digestive system.

Question 7

What happens if pathogens enter the bloodstream?

Answer 7

• They multiply and damage healthy tissue.
• Bacteria release toxins - which make us feel unwell.

Question 8

What are the 2 main roles of the immune system?

Answer 8

1.) Immune system destroys pathogens and any toxins they produce.
2.) Immune system protects us incase same pathogen invades us in the future.

Question 9

What are the 3 ways white blood cells help to defend us against pathogens?

Answer 9

1.) Phagocytosis
2.) Antibody production
3.) Antitoxin production

Question 10

Describe what happens during phagocytosis.

Answer 10

• White blood cells injest pathogens.
• White blood cell uses enzymes to destroy the pathogens.

Question 11

What are antibodies?

Answer 11

• Antibodies are protein molcules produced by white blood cells.

Question 12

What are the 2 main facts about antibodies?

Answer 12

• They are extremely specific to the pathogen’s antigens.
• They remain in the blood for a long period of time: will protect us if we get infected again.

Question 13

How do antitoxins defend us against pathogens?

Answer 13

• Antitoxins bind on to toxins and prevent them from damaging cells.

Question 14

How do antibodies destroy pathogens?

Answer 14

• Antibodies will bind to antigens.
• Clump pathogens together.
• Making phagocytosis quicker!