Immunity

Question 1

Role of the macrophage?

Answer 1

phagocytic cell, hunt pathogens, also can release cytokines in order to signal to other cells in the area

Question 2

What are mast cells?

Answer 2

Found in mucous membranes and connective tissue. when activated they release cytokines and granules to create an inflammatory cascade.

Question 3

Role of natural killer cells?

Answer 3

Kill and destroy cells that are infected in order to stop the spread of pathogen

Question 4

Role od dendritic cells?

Answer 4

are antigen presenting cells, acts as messengers for rest of immune system, Bridge between innate and adaptive

Question 5

Name the physical barriers to pathogens?

Answer 5

skin is slightly acidic and has own flora, body hair, mucous , cillia, ph2 of stomach and alkaline intestine, bile, tears contain lysozyme, sweat, saliva

Question 6

What are the general immune responses?

Answer 6

1. inflammatory - actively brings immune cells both the site of an infection by increasing blood flow to the area
2. complement - an immune response that marks pathogens for destruction and makes holes in the cells membrane

Question 7

Difference between innate and adaptive immunity?

Answer 7

innate is general, non specific so anything determined as non self is a target. Activated by the presence of antigens and their chemical components. no lag phase, no memory

Adaptive relys on B and T cells and more specific to each antigen. Has a lag phase but has memory

Question 8

How do cells sense pathogens?

Answer 8

Pathogen recognition receptors: PRRs

Question 9

4main classes of PRRs?

Answer 9

NLRs
CLRs
TLRs
RLRs

Question 10

What is a PAMP?

Answer 10

pathogen associated molecular pattern: specific to the microorganism and normally essential for pathogen viability. e.g.. flagellin, viral ssRNA and glycans

Question 11

What are defensins?

Answer 11

produced by epithelial cells and phagocytes, bind to phospholipid bilayers and form pores, bury inside and lyse cell. are amphipathic

Question 12

Lymphoid organs?

Answer 12

spleen, thymus, bone marrow and the lymph nodes

Question 13

What ar the 4 steps of the complement system?

Answer 13

1. foreign particles are marked for phagocytosis
2. cytokines and chemokines attract macrophages
3. Proteins destroy membrane causing it to lyse
4. antibodies bind pathogens together - agglutination

Question 14

What is the strucutre of antibodies?

Answer 14

4 proteins, 2 light and 2 heavy chains each has a variable region that is specific to antigens. Interacts with antigen at the FAB point - Fragment antigens binding point

Question 15

Where do T and B cells derive from and mature?

Answer 15

both derive from bone marrow stem cells called hematopoitic
B mature in bone marrow
T mature in thymus

Question 16

What do T cells do?

Answer 16

express recepotros CD4 and CD8 that bind to the receptor molecules MHC1 and MHC2 on the antigen presenting cells. Activate the T cells to differentiate into =

T helper - express CD4 and activate cytoxic T cells and B cells

T regulatory - express CD4 and CD25, distinguish between self and foreign to eliminate autoimmune

Cytotoxic T cells - express CD8 remove pathogens and infected hosts

Question 17

When does inflammation occur?

Answer 17

following, necrosis, trauma, infection, allergy, extreme temperature and foreign body

Question 18

Signals of inflammation?

Answer 18

calor, red, hotness, pain, swelling, loss of function

Question 19

What is acute inflammation?

Answer 19

has a short duration and neutrophils are main response.

Result of damage of infection that affects vasculature

Question 20

Steps of acute inflammation?

Answer 20

1. diameter of blood vessel increases
2. Increase in permeability of blood vessels due to histamine so increase fluid influx into tissue
3. Swelling - oedema
4. reduction in blood velocity caused by vasodilation promoting immune cells to enter tissue

Question 21

What is chronic inflammation?

Answer 21

mainly involves plasma cells, lymphocytes and macrophages.
Can b result of acute inflammation,arthritis, abscesses
Poor vasculation of the bones means poor recovery

Question 22

Steps of chronic inflammation?

Answer 22

tissue destruction, granulation of the wound, fibrosis - proliferation of undifferentiated fibroblasts.
Parcelling off of damaged tissue that cannot be prepared. Fibrous casing around infected areas

Question 23

What is necrosis?

Answer 23

is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Causes cells around it to die too. Requires an external signal e.g. cuts or toxins or burns

Question 24

What is frostbite?

Answer 24

The freezing of the cytosol of cells, it expands and causes rupture of plasma membrane

Question 25

What is ischemia?

Answer 25

loss of blood flow to an area so lack of O2 and nutrients

Question 26

At what point does necrosis become irreversible?

Answer 26

once increase in Ca+ and cell lysis and inflammation process underway

Question 27

What is apoptosis?

Answer 27

programmed cell death, internal signals, used in tissue maintainance and development eg. digits or if DNA is damaged or cells are infected

Question 28

What is apoptosis?

Answer 28

programmed cell death, internal signals, used in tissue maintainance and development eg. digits or if DNA is damaged or cells are infected or to stop necrotic tissue spreading

Question 29

What are apoptotic bodies?

Answer 29

Vesicles containing parts of the lysed cells

Question 30

What genes control apoptosis?

Answer 30

CED3 and CED4 that are inhin=bited by CED9