Pathogens and Non-Specific Immunity

Question 1

List 4 first lines of defence against pathogens

Answer 1

• Eyes (tears contain lysozome)
• Mucus in respiratory tract
• Acid and bacteria in stomach and gut
• Skin and skin flora, which out compete pathogens. Sebum kills microbes

Question 2

How do gut bacteria prevent pathogens from surviving?

Answer 2

• Out compete for space and nutrients

- Produce lactic acid which deters pathogens

Question 3

Name four non specific responses

Answer 3

• Inflammation
• Lysozyme action
• Interferon
• Phagocytosis

Question 4

Summarise inflammation

Answer 4

• Damaged white cells release histamines
• Arterioles dilate
• Capillaries become more permeable
• Blood flow increases plasma
• White blood cells and antibodies leak into tissues
• Edema

Question 5

Summarise lysozyme action

Answer 5

• Enzyme found in tears, sweat and the nose

- Breaks down bacterial cell walls

Question 6

Summarise interferon

Answer 6

A chemical released from infected cells prevents viral replication

Question 7

Summarise phagocytosis

Answer 7

• White blood cells engulf, digest and destroy bacteria and other foreign material
• Foreign material enclosed in vesicle
• Cell secretes digestive enzymes from lysosomes into the vesicle
• Include neutrophils and monocytes
• Also involved in specific response