10.7 Innate and Adaptive Immunity

Question 1

define immunity

Answer 1

condition where body is protected from various threats (pathogens, toxins, cancer cells)

Question 2

define both immunities

Answer 2

• innate immunity: fully functional without previous exposure to substances
• adaptive immunity: initiated and amplified after specific recognition of these substances

Question 3

what are the four types of innate immunity

Answer 3

• physical/chemical
• inflammation
• phagocytes and natural killer cells
• protective proteins

Question 4

describe physical/chemical barriers

Answer 4

innate immunity

• physical: skin, mucous membrane lining respiratory, digestive, urinry tracts serve as mechanical baarriers to entry of pathogens
• upper respiratory tracts lined w ciliated cells that sweep mucus and trapped particles up into the throat where they can be swallowed or expelled
• secretion of oil glands in the skin contain chemicals that weaken/kill bacteria on skin
• stomach acid an acid pH that kill many types of bacteria

Question 5

describe the inflammatory response

what initiates it, 4 steps

Answer 5

• damage to tissues (physical trauma, chemical agents, pathogens) intiates it
  1. injured tissues cells + mast cells respond to damage by releasing histamine which causes capillaries in area to dilate become permeable so fluid can escape
  2. macrophages and dendritic cells phgacytize pathogens and release cytokines
  3. WBC: neutrophils and monocytes (which become macrophages) squeeze through the capillary wall and phagocytize pathogens into endocytic vessicle that fuses with lysosome inside cell
  4. if blood vessels are damaged, blood clotting walls off capilary and prevents blood loss

Question 6

describe the 4 cardinal signs and how they are caused

Answer 6

• swelling: capillaries in area dilate from release of histamine, become more permeable and allows fluid to escape
• pain: swollen area stimulate free nerve endings
• skin redden and feel warm: increased blood flow

Question 7

why are anti inflammatory medications taken

Answer 7

• minimize effects of inflmmation

- Aspirin, ibuprofren, cortisone

Question 8

histamine

Answer 8

chemical that binds to receptors on endothelital cells lining blood vessels, causes capillaries in area to dilate and become more permeable allowing lymph to escape

Question 9

phagocytes

Answer 9

“eating cell”:

• neutrophils first WBC to enter inflamed area from blood, accumulate to form pus
• when encountering a pathogen, will phagocytose the pathogen into an endocytic vesicle which fuses w lysosome in side cell, lysomome has an acid pH that activates hydrolytic enzymes and various reactive O2 compounds, destroys pathogen

Question 10

natural killer cells

Answer 10

-large, granular, lymphocyte like cells
kill virus infected cells by cell to cell contcat
induce to apoptosis, kill cells that lack major histocompatibility class 1

Question 11

why are natural killer cells considered part of the innate immune system

Answer 11

-do not recognize specific viral or tumour antigents and do not proliferate when exposed to a particular antigent

Question 12

what does the adaptive immune system recognize

Answer 12

recognizes, responds to, eliminates antigens from body

-activty of B and T cells

Question 13

antigen

Answer 13

molecule that stimulates an adaptive immune response

Question 14

why are B and T cells able to recognize antigens

Answer 14

have specific antigen receptors- a plasma membrane proteins whose shape allows then to bind to a particular antigen

Question 15

where are B cells activated

Answer 15

-spleen or lymph nodes when their receptors bind to specific antigens

Question 16

what are cytokines

Answer 16

chemical messengers that influence activity of other immune cells

Question 17

how are cytokines important

Answer 17

T cells secrete cytokines which stimulate B cells to divide into plasma cells or memory B cells

Question 18

what are plasma cells

Answer 18

specialized for the secretion of antibodies

Question 19

what are antibodies

Answer 19

secreted form of receptor B cell that was activated

Question 20

what are memory B cells

Answer 20

if same antigen enters system again, memory B cells quickly divide and give rise to more plasma cells capable of rapidly producing the correct type of antibody

Question 21

describe antibody mediated immunity

Answer 21

aka humoral immunity because these antibodies are present in blood and lymph

• exposure to pathogen
• B cells activated, form into plasma cells and memory B cells
• once infection clearned from body, new plasma ceases to develop and most of those present undergo apoptosis

Question 22

describe the structure of immunoglobulins

Answer 22

Y shaped with 2 arms
-each arm has a long (heavy) polypeptide chain and a short (light) polypeptide chain
chains have a constant region where amino acids are set and a variable region here the sequence of amino acids varies between antibodies

Question 23

describe the antigen binding site

Answer 23

-on antibody, variable region forms the antigen binding site, combines w antibody at this region in a lock and key manner

Question 24

immune complexes

Answer 24

reaction that produces complexes of antibodies combines w antigens and mark the antigen for destruction

Question 25

how do antibodies “neutralize” viruses or toxins

Answer 25

prevent binding to cells

Question 26

describe T cells

Answer 26

• has unique T cell receptor similar to receptors on B cell but there is no secreted form of T cell
• unable to recognize antigen without MHC (major histacompatibility complex) protein on the surface of another cell
• helper T cells and cytotoxic T cells

Question 27

describe the difference between helper T cells and cytotoxic T cells

Answer 27

• helper T cells only recognize antigen presented by specialized antigen-presenting cells (APCs) with MHC II class protein on surface
• cytotoxic T cells only recognize antigen presented by cell types with MHC I class proteins on surface
• often kill cells they recognize
• kill cells depending on storage vacuoles tht contain molecules of perforin and granzymes

Question 28

what is the difference between antibody mediated immunity and cell mediated immunity

Answer 28

antibody: involved antibodies
cell: involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.

Question 29

describe cell mediated immunity in relation to perforin and granzymes

Answer 29

• cytotoxic T cells binds to a virus infected cell or cancer cell that has a antigen MHC class I protein on it
• Tc cell realeases perforin which forms pores in the plasma membrane of abnormal cell
• pores formed allow granzymes to enter target inducing a poptosis
• Tc cell capable of then moving on to kill another target cell

Question 30

what happens durning the phagoctyosing of the pathogen

Answer 30

-endocytiv vessel fuses w lysosome, lysosome has acidic pH that activates hydrolytic enzymes, and O2 compounds destory pathogen