Defense Systems

Question 1

What are infections caused by?

Answer 1

Pathogens (disease-causing micro-organisms)

Question 2

What is the body’s immune response stimulated by?

Answer 2

• pathogens
• foreign cells
• toxins

Question 3

What are the components of the body’s first line of defense?

Answer 3

• skin
• mucous membranes (produce mucous to trap particles and cilia remove them)
• saliva & tears (contain anti-bacterial enzyme called lysozyme)
  acidity of skin & membranes kill micro-organisms

Question 4

What are the components of the body’s second line of defense?

Answer 4

• primary and secondary response
• using internal cells & chemicals

Question 5

What does the primary response entail?

Answer 5

• tries to prevent infection spreading
• chemicals (histamines) cause inflammation
• increased blood flow & oxygen
• oedema (swelling)
• fever

Question 6

What does the secondary response entail?

Answer 6

• cells that ingest & destroy foreign cells & toxins
• destruction of specific pathogens
• keeping a memory of the response