Immune System & Resistance to Disease

Question 1

What are the types of resistance?

Answer 1

1. Innate defences/immunity. 2. adaptive defences/immunity

Question 2

What is innate defence?

Answer 2

prevent entry of microbes into body or remove foreign material. consists of surface barriers and innate internal defences that act as the first and second lines of defence/

Question 3

What are the types of innate defences?

Answer 3

1. physical barriers - skin, mucous membrane 2. mechanical barriers - coughing, cilia beating, flow of tears, sweat, mucus. 3. chemical barriers - gastric acid, lysozyme (in saliva and tears), interferons. 4. normal flora - outcompete newcomers/bacteria. 5. phagocytes - macrophages and neutrophils (grabs bacteria and engulfs it). 6. inflammation - local tissue damage leads to release of chemicals like histamine which is a vasodilator form mast cells. result in vasodilation causing swelling, heat, redness, pain, so loss of fxn. attracts neutrophils within an hour and then macrophages. 7. fever - immune cells and microbe chemicals trigger release of prostaglandins in hypothal, which increases temp. 8. natural killer cells - a type of lymphocyte that can non-selectively kill cancer cells and virus-infected body cells.

Question 4

What are interferons?

Answer 4

they’re produced by virus infected cells, and trigger mechanisms in nearby uninfected cells that prevent infection. so telling neighbouring cells that there’s a virus.

Question 5

What decreases prostaglandin synthesis?

Answer 5

aspirin, ibuprofen, acetaminophen. so decreases fever.

Question 6

What is adaptive defences/immunity?

Answer 6

production of specific lymphocyte or antibody against a recognized antigen.

Question 7

What is an antigen?

Answer 7

prot/polysaccharide - recognized as foreign by immune system. ie. parts of bacteria. viruses, pollen, parasites, transplants.

Question 8

What is an antibody?

Answer 8

plasma prot (y globulin) - matches a specific antigen - produced by plasma cells.

Question 9

What is the adaptive immune response?

Answer 9

1. phagocytes (ie macrophages) - eat invader and displays parts of the antigen on its surface. 2. Helper T-cell - binds to antigen-phagocyte complex and is activated. activation causes it to proliferate and produce more TH.

Question 10

What do the chemicals released from the T-helper cells activate?

Answer 10

1. cytotoxic T-lymphocytes - proliferate and directly destroy either virus containing cells, cells altered by cancer, or cells from transplanted organs. this is cell-mediated immunity. 2. B cells - proliferate and convert to plasma cells that produce antibodies. this is humoral/antibody mediated immunity.

Question 11

What is cell-mediated immunity?

Answer 11

adaptive immunity response done by cytotoxic t-lymphocytes which directly kill invaders.

Question 12

What is humoral or antibody mediated immunity?

Answer 12

adaptive immunity response done by B cells that convert to plasma cells and produce antibodies to get rid of antigen.

Question 13

What to memory B/T cells do?

Answer 13

produced from chemicals released by helper T-cells. long-lived and permit a rapid response on the next encounter with the same antigen. so they remember the antigen and can enact a quicker response.

Question 14

What are the types of humoral immunity? (list)

Answer 14

1. active - lasts years 2. passive - last weeks/as long as the antibody’s present.

Question 15

What is active humoral immunity?

Answer 15

body makes antibodies, memory B cells after; a. exposure to pathogen = natural immunity b. injection with killed/inactivated pathogen (vaccination) = artificial immunity.

Question 16

What is passive humoral immunity?

Answer 16

a. natural immunity; mother - fetus/baby across placenta and milk. b. artificial immunity; artificially produced antibodies from another person, animal or monoclonal are injected. ie tetanus, rabies, snake bite antivenins, Rh factor. mops up antigen before it can trigger an immune response in person.