U4A1: 7C SECOND LINE OF DEFENCE

Question 1

cellular components of the second line of defence

Answer 1

phagocytes
eosinophils
mast cells
natural killer cells

Question 2

phagocytes

Answer 2

undergo phagocytosis. includes
- neutrophils
- macrophages
- dendritic cells

Question 3

phagocytosis

Answer 3

1. pathogen is engulfed (endocytosis)
2. pathogen is fused with lysosome
3. enzymes start to degrade pathogen
4. pathogen is broken into small fragments
   (5. fragments of antigen presented on cell surface)

Question 4

neutrophils

Answer 4

leukocyte that engages in phagocytosis and the release of cytokines.

Question 5

macrophages

Answer 5

leukocyte that engages in phagocytosis and antigen presentation.

Question 6

dendritic cells

Answer 6

leukocyte that engages in phagocytosis and antigen presentation.

Question 7

natural killer cells

Answer 7

interacts with cells. when it locates a cell with non-self antigens presenting on its MHC I marker, stimulating cell death via apoptosis.

Question 8

mast cells

Answer 8

live in connective tissues throughout the body. when they detect injury to surrounding cells or stimulated by antigens/allergens, they become activated and degranulate, releasing histamine.

Question 9

eosinophils

Answer 9

cells that help destroy pathogens that are too large to be phagocytosed.

Question 10

non-cellular components of the second line of defence

Answer 10

interferons
complement proteins
fever

Question 11

interferons

Answer 11

type of cytokine that interacts with receptors on neighboring cells, causing them to undergo changes which make them less susceptible to viral infection.

Question 12

complement proteins

Answer 12

there are a number of different complement proteins that together form the complement system. the major outcomes of the complement cascade are opsonisation, chemotaxis, and lysis.

Question 13

opsonisation of complement proteins

Answer 13

complement proteins stick on the outside surface of pathogens, making it easier for cells such as phagocytes to recognise them as foreign.

Question 14

chemotaxis of complement proteins

Answer 14

complement proteins gather near a pathogen and attract phagocytes to it, making it more likely to be destroyed.

Question 15

lysis of complement proteins

Answer 15

complement proteins join together on the surface of pathogens, forming a membrane attack complex, which creates pores in the membrane. this destroys the pathogen via the sudden burst of fluid into the pathogen, causing it to burst.

Question 16

fever

Answer 16

temporary incease in body temperature; many pathogens cannot survive at these elevated temperatures.

Question 17

inflammation

Answer 17

the process of inflammation increases blood flow to injured area, bringing a greater number of immune cells and components to help fight pathogens.

Question 18

process of inflammation

Answer 18

initiation, vasodilation, migration

Question 19

initiation of inflammation

Answer 19

the pathogen is introduced, immune cells release cytokines and mast cells release histamine.

Question 20

vasodilation of inflammation

Answer 20

histamine binds to blood vessel receptors. widening blood vessels and increasing blood flow.

Question 21

migration of inflammation

Answer 21

vasodilation allows immune system components to enter site of injury. includes
- complement proteins: attracted to pathogens, making it easier for phagocytes to destroy them.
- phagocytes: guided by the cytokines to injury where they phagocytose.

Question 22

part of the immune system

Answer 22

innate or non-specific