Immunity two

Question 1

list physical barriers

Answer 1

skin
-physical barrier
-sebum
mucous membranes
-with cilia for bronchi
saliva and urine: wash

Question 2

list chemical barriers

Answer 2

tears and saliva - lysozyme

urine and stomach acid - too acidic

Question 3

other barrier?

Answer 3

commensal

Question 4

3 properties of innate immunity

Answer 4

• Occurs relatively rapidly
• Non specific
• No immunological memory

Question 5

how do immune cells come about

Answer 5

haematopoietic stem cells
pluripotent stem cells
myeloid progenitors
-T
-B
-NK
lymphoid progenitors
-eosinophil
-basophil
-neutrophli
-monocyte

Question 6

what do basophils, eosinophils and neutrophilshave in common?

Answer 6

granula
short lived
found in blood (not abundant in tissues till recruited)

Question 7

what happenst to monocytes?

Answer 7

go into tissues and turn into macrophages

Question 8

what are the 3 phagocytic cells?

Answer 8

dendritic cells, macrophages, neutrophils

Question 9

how is phagocytosis initiated?

Answer 9

pathogen associated molecular patterns and pattern recognition receptors bind

Question 10

examples of pathogen associated molecular patterns?

Answer 10

lipopolysaccharides

carbs and proteins

Question 11

how are intracellular pathogens gotten rid of?

Answer 11

natural killer cells

Question 12

describe complement system

Answer 12

pathogen and complement proteins collide, triggers cascade of reactions that aids cells in identifying pathogens

Question 13

steps in inflammatory response?

Answer 13

mast cells and macrophages –> histamines –> permeable capillaries
fluid, proteins, clotting factors enter tissue –> clotting
cells release chemokines which attract more phagocytes
phagocytes and monocytes phagocytose bacteria
healing

Question 14

features of adaptive immunity?

Answer 14

• Occurs over time
• Specific – due to clonal selection and expansion
• Immunological memory

Question 15

differences in clonal selection between t cells and b cells?

Answer 15

t cells - antigens attached to MHC markers on dendritic cells
b cells - antigens are presented intactly.

Question 16

describe t cell receptors

Answer 16

2 pp chains, which variable and constant regions

Question 17

helper t cell role?

Answer 17

cd4 receptors bind to antigens presented on MHC class II. clonal expansion - forms more helper T cels amd memory cells. releases cytokines which enables other cells to be activated

Question 18

cytotoxic t cell role?

Answer 18

cd8 receptors bind to antigens presented on MHC class I barkers. clonal selection and expansion to cytotoxic t cells (perforin and granzyme) and memory cells
-operate on cells that have already been infected.

Question 19

describe B cell role

Answer 19

surface antigens bind to free antigens –> clonal selection and expansion –> memory B cells and plasma cells which produce antibodies.

Question 20

MHC class II markers are found on

Answer 20

only APC’s

Question 21

MHC class I markers are found on

Answer 21

all nucleated cells (including APCS)

Question 22

describe structure of antibodies

Answer 22

constant region (carboxy terminus; contains antigen binding site) and variable region (amino terminus)
light chain and heavy chain

Question 23

IgM?

Answer 23

act first
opsonises pathogens and makes it more susceptible to phagocytosis (constant region recognised by phagocytes)
serum

Question 24

IgG

Answer 24

act over some time
neutralise extracellular toxins and viruses
serum

Question 25

IgA

Answer 25

serum and secretions

secreted across mucosal surfaces - gut and breast milk

Question 26

IgE

Answer 26

found beneath epithelial surfaces.

Question 27

describe the 3 non sinus segments

Answer 27

primary lymph follicle (B cells)
secondary lymph follicle (includes germinal centre)
paracortical area (T cells)
medullary cords (macrophages)

Question 28

desciribe sinus areas

Answer 28

medullary sinus

marginary sinus

Question 29

describe vessles

Answer 29

artery/vein

afferent and efferent lymph vessels

Question 30

how do activated APC’s get to lymph nodes?

Answer 30

afferent lymph vessel

Question 31

where are unactivated T and B cells?

Answer 31

flowing through blood vessels through lymph nodes

Question 32

why do unactivated T and B cells flow through lymph nodes from time to time?

Answer 32

because there’s a higher chance that they;ll interact with APC that has their complementary antigen

Question 33

what happen APC enters complementary helper T cell?

Answer 33

clonal selection and expansion of helper T cell. releases cytokines.

Question 34

what happens to B cells in the lymph node?

Answer 34

parts of pathogen come through afferent lymph - if small on their own; if large through macrophages. B cells ingest and display them. Helper T cell’s CD4 receptors bind to B cells MHC II markers. This activates B cell; clonal selection and expansion occurs in the lymph node.

Question 35

once helper T and b cells are activated, what happens to lymphocytes?

Answer 35

enter efferent lymph vessel, then thoracic duct, then bloodstream. follow chemokine gradient to the site of infection and kill. note: cytotoxic T cells still need to attach to MHC I markers of infected cells.