immune system

Question 1

the immune system is a set of — — that works with the — system to — — — — (aka pathogens) that enter the body

Answer 1

specialized cells; lymphatic; fight off foreign substances

Question 2

there are two types of defenses

Answer 2

-innate (non-specific) defenses
-acquired (adaptive) defenses

Question 3

innate (non-specific) defense

Answer 3

-work quickly but arent specialized for individual pathogens
–skin and mucous membrane

Question 4

acquired (adaptive) defense

Answer 4

-works slowly but provides specialized and long-lasting defense
–humoral immunity and cell-mediated immunity

Question 5

innate resistance starts with barriers

Answer 5

-external barriers: prevent pathogens from entering the body
-internal barriers: activated once pathogen passes into body tissues

Question 6

external barriers

Answer 6

-SKIN: keratinized cells create a physical barrier
–produces oil and sweat which inhibit growth of bacteria
-MUCOUS MEMBRANE: mechanical elimination
–mucous physically traps pathogens and cilia of the respiratory track can sweep them towards the mouth for removal.
-SECRETIONS: gastric juice from stomach, saliva, and tears all contain enzymes that kill pathogens

Question 7

internal barriers

Answer 7

-PHAGOCYTES: “eat” foreign invaders
–neutrophils: kill bacteria, then die (creating pus)
–macrophages: move with cytoplasmic extensions to ingest pathogens
-NATURAL KILLER CELLS: lyse (explode) infected/abnormal body cells based on a lack of “self” surface receptors
-IMFLAMMATION:
–basophils and mast cells stim, blood vessels to dilate/widen
–swelling (edema) allows macrophages to quickly arrive through vessels
–pyrogenic chems cause fevers, which increases cell metabolism to speed up repair
-ANTIMICROBIAL PROTEINS:
–complement proteins: work with other defenses by lysing pathogenic bacteria or making pathogens for easier phagocytosis (opsonization)
–interferons: warning signal proteins secreted by virally-infected body cells. these are a type of cytokine
—cytokine: chem signals used to help cell communicate during immune response

Question 8

if the non-specific defenses dont stop the infection, the body will create an immune response — to that —

Answer 8

specific, pathogen

Question 9

substances that trigger responses are called —

Answer 9

antigens

Question 10

the cells responsible for the specific response are called —

Answer 10

lymphocytes

Question 11

lymphocytes produce — that match certain —

Answer 11

antibodies; antigens

Question 12

the acquired immunity portion of the immune response must be able to

Answer 12

1. discriminate between self and non-self antigens
2. recognize a specific antigen among trillions of possible substances
3. generate a large diversity of antibodies so any possible substance can be recognized and eliminated
4. provide memory of antigens

Question 13

discriminate between self and non-self antigens

Answer 13

lymphocytes that act against self-antigens are destroyed

Question 14

recognize a specific antigen among trillions of possible substances

Answer 14

each lymphocyte only has surface receptors for one antigen

Question 15

provide memory of antigens

Answer 15

a 2nd exposure to an antigen is immediately recognized and infection is barely noticed

Question 16

two types of acquired (specific) immunity

Answer 16

-humoral response
-cell-mediated response

Question 17

humoral response

Answer 17

-involves B cells
-responds to antigens before they infect body cells

Question 18

cell-mediated response

Answer 18

-involves t-cells
-responds to body cells that have already been infected with foreign pathogens

Question 19

immunity can be — or —

Answer 19

earned; borrowed

Question 19

steps of the humoral response

Answer 19

1. B-lymphocytes (B-cells) recognize a foreign antigen
2. B cells rapidly divide creating cloned plasma b cells and memory b cells
3. memory b cells are long-lived and produce a swift and strong response if the same antigen is encountered in the future (“secondary response”)
4. the antibodies produced by the plasma B cells can:
   -neutralize the antigen by physically surrounding it
   -immobilize the antigen by agglutination (clumping, which flags macrophages to go eat it)
   -activate macrophages to destroy antigen

Question 20

active immunity is — because it is developed by the creation of our own antibodies

Answer 20

earned

Question 21

passive immunity is when we — the immunity that another individual has already created

Answer 21

borrow

Question 22

for cell-mediated immunity, in order to amplify the immune response, — can also act as — — —

Answer 22

B-cells; antigen-presenting cells

Question 23

antigen-presenting cells — — and present pieces of the antigen to other immune cells. this is the sounding alarm for an infection to recruit more warriors for the fight

Answer 23

engulf antigens

Question 24

antigen-presenting cells include

Answer 24

B-cells, macrophages, and dendritic cells

Question 25

the antigen fragment is presented on a — known as an MHC-II. T-cells will bind to this and mount a — response against the antigen

Answer 25

receptor; stronger

Question 26

steps in the cell-mediated response

Answer 26

1. after the antigen-presenting cells display the foreign antigen to a helper T-cell, the T-cell is activated
2. a signaling cascade begins, creating more helper and memory T-cells
3. some of the cytokine signals activate cytotoxic T-cells, which bind to infected body cells and cause apoptosis
4. regulating T-cells release chemicals to slow the immune response after the antigen is destroyed

Question 27

which cells are used to react quickly to a secondary infection (re-infection with a previous pathogen)

Answer 27

memory b and memory t-cells

Question 28

how can the secondary response be artificially produced?

Answer 28

vaccines can help the body mimic the first infection