Innate immune system

Question 1

Blood composition

Answer 1

blood is composed of plasma and cells 
erythrocytes (RBC) 
Leukocytes (WBC)  
platetes (clotting) 
water -91%
proteins

Question 2

Erythroid

Answer 2

red blood cells

Question 3

Myeloid

Answer 3

granulocytes, monocytes, dendritic cells, platelets (innate immune cells)

Question 4

Lymphoid

Answer 4

B and T lymphocytes (adaptative immune cells) - kill other cells

Question 5

3 blood cell types

Answer 5

Erythroid
Myeloid
Lymphoid
all of these are derived from hematopoietic stem cells in the bone marrow

Question 6

neutrophils

Answer 6

75% of leukocytes (granulocytes) in the blood
highly phagocytic - eat and kill
numbers increase during infection

Question 7

Eosinophils

Answer 7

1-6% of leukocytes (granulocytes) in the blood
release toxic granules to kill parasite
numbers increase in blood during parasitic infection

Question 8

Basophils

Answer 8

0.5% of leukocytes (granulocytes) in the blood

release granules that can mediate allergic reactions or fight infection really uncommon to see in a blood smear

Question 9

granulocytes

Answer 9

circulate in the blood and can move into tissue during inflammation/ infection

Question 10

granulocytes in tissue

Answer 10

mast cells line mucosal surfaces (not found in blood)

release granules that attract white blood cells to areas of tissue damage

Question 11

Monocytes and macrophages

Answer 11

monocytes present in blood - low phagocytosis
leave blood - develop into macrophages in tissue eg spleen and liver. - high phagocytosis
monocytes have a large nucleus, in tissue the then go into macrophages and become highly phagocytic and eat anything.

Question 12

macrophages

Answer 12

become resistant (sessile) or move through tissue (migratory)
3 important functions
- phagocytosis
- release of chemical messengers
- show information about pathogenic microbes to T cells (linking innate and adaptive immunity)
alert other immune cells when where is an infection

Question 13

Dendritic cells

Answer 13

found in low numbers in blood and all tissues in contact with the environment
phagocytic
most important cell type to trigger adaptive immune response
very potent so don’t need many of them`

Question 14

How do immune cells move around the body?

Answer 14

cells are carried in the blood and in the lymph
cells can leave he blood and enter tissues when they get the right signals
lymph tissue collects into lymphatic vessels. these drain into lymph nodes

Question 15

4 cardinal signs of inflammation

Answer 15

heat
redness
swelling
pain 
vasodilation, leaky blood cells allow cells to get from blood into tissue and help us fight any invading organisms. this leads to swelling as there are a lot of cells going to that place and leads to heat production and the whole process is painful. also a loss of function because of this.

Question 16

fever (heat)

Answer 16

temp above 37
re-setting of thermostat (hypothalamus)
pyrogens make us hot
phagocyte produce a chemical messenger and pyrogen interleukin-1 after ingesting bacteria
a decrease in phagocytosis will lead to a decrease in the release of L-1 and that will lead to a decrease in temperature

Question 17

inflammatory response 1

Answer 17

mast cells - granular cites and have preformed vesicles that are able to be released upon damage or exposure to pathogens
macrophages- come along and phagocytose

Question 18

mast cells release

Answer 18

histamine - vasodilation of blood vessels
prostaglandins and leukotrienes - vascular permeability of blood vessels
all of these are within the vesicles in the mast cells

Question 19

inflammatory response 2

Answer 19

the vessels become permeable and more blood flow makes injury red. the white blood cells can now squeeze through the walls of the blood vessel and to the tissue where it has been injured because of increased permeability.
phagocytes (neutrophils) come along from the blood stream and clean up any left over pathogens in the injury area. these can lead to puss over a clearance of infection.

Question 20

response to virus

Answer 20

innate antiviral protein - type 1 interferon (TFN)

Question 21

type 1 interferon (IFN)

Answer 21

is a chemical messenger or cytokine produced by many host cells to combat viruses
cells communicate to each other by telling each other there is a virus and this limits the spread of infection
the cells destroy RNA and reduce protein synthesis
signalling neighbouring to undergo apoptosis
activates immune cells

Question 22

Toll-like receptors

Answer 22

pattern recognising receptors in or on innate cells
bind to common microbial molecular patterns
TLR engagement drives many innate immune mechanisms
like phagocytosis, cytokine release, interferon release
some are in cell membranes and some are on the inside.

Question 23

TLR 4 and 5

Answer 23

are on the cell membrane and send inflammatory signals to the inside of the cell

Question 24

TLR 9 and 3

Answer 24

are in the nucleus
9 binds to bacterial DNA
3 binds to viral double stranded RNA.
inflammatory responses are triggered

Question 25

stages of phagocytosis `

Answer 25

1. pseudopodia (false foot come out) surrounds microbes gives them a hug.
2. microbes are adhered to phagocyte and are engulfed
3. ingestion of microbes into vacuole ie. phagosomes
4. fusion of vacuole and lysosome (has digestive enzymes and low pH to kill)
5. killing and digestion of microbe
6. elimination (exocytosis) of dead microbe, like waste produce of phagocyte

Question 26

killing and digestion of phagocytosed microbes

Answer 26

low pH - acid environment 
reactive oxygen (hydrogen peroxide) and reactive nitrogen intermediates 
enzymes
- protease - break down proteins 
- lipase - break down lipids 
- nuclease - break down nuclear material

Question 27

the complement cascade

Answer 27

complement - 9 major proteins/ protein complexes.
act in a sequence to clear pathogens from blood and tissue
label - opsonisation
recruitment - chemotaxis
destroy - lysis

Question 28

3 complement pathways

Answer 28

classical - antibody bound to pathogen binds to complement
alternative - pathogen binds to complement to surface/ pathogen
lectin - carbohydrate components of microbes bind to complement

Question 29

3 outcomes from the complement cascade

Answer 29

label
destroy
recruit

Question 30

label (complement cascade)

Answer 30

opsonisation = coating of microbe with an antibody and or complement fragment C3b
leads to uptake by phagocyte, can lead it with antibody leads to destruction

Question 31

destroy (complement cascade)

Answer 31

membrane attack complex formation -pores in bacterial cells causes water to rush in and cause lysis of the cell and destruction. initiated by microbe being covered with C9.

Question 32

recruit (complement cascade)

Answer 32

phagocytes are attracted to the site
mast cells degranulated by C3a and C5a
inflammatory mediators released including proteins that attract phagocytes - chemical trail.