Unit 6.3 and 11.1 - Response to Pathogens

Question 1

What are antigens

Answer 1

foreign cell-markers that provoke a response in the human body

Question 2

What are antibodies

Answer 2

proteins that are specific to an antigen and work to remove the antigens through different ways

Question 3

Explain how non-specific immune responses happen

Answer 3

• Phagocytosis occurs, engulfing a pathogen
• Innate, non-specific immune response
• lysosome and vacuole/vesicle containing pathogen combine to create a phagolysosome where the pathogen is ingested
• antigens are presented on the membrane of the phagocyte for specific immune response

Question 4

Explain how specific immune responses happen

Answer 4

• non-specific occurs first, where phagocytes/dendritic cells/macrophages transport to the lymph nodes
• response is specific to a specific pathogen via the creation of specific antibodies
• helper t-lymphocytes receive the antigens on the macrophages and release cytokines, these then activate b-lymphocytes
• these cells then replicate via mitosis and become plasma cells where they produce antibodies
• antibodies kill the pathogens in the blood stream
• some plasma cells are retained in case of secondary infection and allow the body to be resistant to the specific pathogen for a prolonged period

Question 5

Explain how an allergen causes an immune response

Answer 5

An antigenic determinant on an allergen causes memory plasma cells to release antibodies, these bind to mast cells containing histamine. The antigens on the allergen then bind with the variable region of the antibody where histamine is released after allergen binds. This is an allergic reaction.