Primary Defence And Phagocytosis

Question 1

What is the immune system?

Answer 1

System of specialised cells and organs (thymus, bone marrow, lymph nodes) that protect an organism from foreign bodies

Question 2

What are the 2 immune responses?

Answer 2

Innate and adaptive

Question 3

What is innate immune response?

Answer 3

• first line of defence
• non specific (immediate and same response for all pathogens)
• no immunological memory
• includes phagocytes, neutrophils, macrophages

Question 4

What is adaptive immune response?

Answer 4

• specific towards a particular pathogen (slower response)
• immunological memory
• includes lymphocytes

Question 5

What are the 2 types of lymphocytes in adaptive immune response?

Answer 5

• T lymphocytes (cell mediated response)
• B lymphocytes (humoral repsonse)

Question 6

What is the first line of defence?

Answer 6

Natural barriers that reduce the risk of infection (often exterior defences)

Question 7

What are some examples of first line of defence?

Answer 7

• skin and membranes
• acid in stomach
• ciliated epithelium
• sweat
• blood clots
• tears

Question 8

Explain why ciliated epithelium protects?

Answer 8

Goblet cells secret mucus and strap microbes in inhaled air

Question 9

Explain why sweat protects

Answer 9

Contains antimicrobial agents

Question 10

Explain why tears protect

Answer 10

Contains lysozymes with break down bacterial cell walls that contain murein

Question 11

Describe the steps of phagocytosis

Answer 11

1. Phagocytes recognise pathogens due to foreign antigens on their surface
2. Phagocyte engulfs pathogen and forms phagocytic vesicles
3. Lysosome fuses with phagocytic vesicle
4. Lysozymes break down pathogen