Immunology

Question 1

What is immunological unresponsiveness called to an antigen?

Answer 1

Tolerance

Question 2

Define self tolerance

Answer 2

When immune cells and other body cells coexist peaceably

Question 3

What are the physical barriers in a body?

Answer 3

Skin and mucous membranes in the respiratory system, digestive tract and the reproductive tracts

Question 4

What is mucus made up of?

Answer 4

Water 95%
Mucin (2%)
Salt (2%)

Question 5

What is the function of the mucus?

Answer 5

Stops attachment of invading pathogens
Contains antimicrobial enzymes such as growth inhibitors and enzyme inhibitors and lysins and immunoglobulins (help destroy pathogens)

Question 6

What is the immune system comprised of?

Answer 6

The innate immune system and the adaptive immune system.

Question 7

When does the adaptive immune system become active?

Answer 7

When the attack is severe or prolonged

Question 8

Where can you find macrophages in the body?

Answer 8

Tissue

Question 9

What is the name given to the vesicle formed in the phagocyte?

Answer 9

Phagosome

Question 10

What is a phagolysosome?

Answer 10

The phagocytic vesicle that the lysosome has fused with

Question 11

Describe what happens to a monocyte in the blood?

Answer 11

They travel around the blood for three days and enter a tissue (through cracks in the epithelieal cells of the capillary wall) where they mature into macrophages

Question 12

What happens when macrophages encounter a pathogen?

Answer 12

They are activated, constrict blood flow away from injury site (constricts blood flow - redness)
They grow and give off chemical signals and debris from eating

Question 13

What is the result of the macrophage chemicals on the epithelial cells lining the capillary?

Answer 13

Causes epithelial cells to contract and spaces to form between cells. Fluid leaks into the tissue and causes swelling. Also increases the recruitment of more monocytes and other immune cells - release of cytokines

Question 14

What are the three states of readyness of macrophages?

Answer 14

Resting - small sips of their surrounding environment (low MHC 2 levels)
Primed - Larger sips when they come across something interesting (higher levels of MHC 2) - act as APC (antigen presenting cell)
Hyperactivated - they receive a strong direct signal from the pathogen

Question 15

What type of phagocytic cell isn’t an APC?

Answer 15

Neutrophil, they are also the most abundant white blood cell

Question 16

What guides the migration of neutrophils towards the site of inflammation?

Answer 16

Follow a trail of chemical attractants and chemokines, process known as chemotaxis

Question 17

What is the immune system component for helping combat parasites?

Answer 17

Eosinophils

Question 18

What do the granules of eosinophyls contain?

Answer 18

Enzymes
Make histamines and heparin.

Question 19

What other type of cell apart from Eosinophil?

Answer 19

Mast cells, anaphylactic shock caused by mast cell degranulation. Contains histamine

Question 20

What is the third type of cell that is derived from granulocytes?

Answer 20

Basophils

Question 21

What is compliment?

Answer 21

Protein in the blood that’s responsible for cell killing (lysing)

Question 22

What recruits and activates the compliment proteins?

Answer 22

The adaptive immune system

Question 23

How many activation pathways exist form compliment proteins?

Answer 23

3 pathways, Lectin, Classical, alternative

Question 24

What is the result of each activation pathways?

Answer 24

Lysis and opsonisation (identifying the invading particle to the phagocyte). makes a hole in the pathogen. Also enhancing immune response, ie help with inflammation

Question 25

What is the compliment protein comprised of?

Answer 25

Over 30 serum proteins

Question 26

Which effector mechanisms which activate compliment are part of the innate immune system?

Answer 26

Alternative and lectin pathways are of the innate immune system?

Question 27

What is the central event in the activation of compliment?

Answer 27

It is the proteolysis of C3, the most abundant compliment protein.

Question 28

Why is the classical effector mechanism considered to be part of the adaptive immune system?

Answer 28

It involves the use of antibodies

Question 29

When is the membrane attack complex activated?

Answer 29

When the C9 the final protein is bound, forms a pore in the cell

Question 30

What safeguards are in place to stop compliment attacking our own cells?

Answer 30

Decay acceleration protein - cell surface protein in human cells - leads to break down of MAC precursor

Question 31

Besides lysis, what other functions does compliment have?

Answer 31

Opsonisation, recruiting other immune cells (neutrophils and macrophages)
Stimulates inflammation - mast cells and neutrophils
Activates B cells and Ab production

Question 32

Where do you find viruses?

Answer 32

Within the cell

Question 33

Where can you find natural killer cells?

Answer 33

Blood, spleen and it then migrates to the tissue

Question 34

What can natural killer cells destroy?

Answer 34

Tumour cells, virus infected cells, bacteria, parasites and fungi

Question 35

How do the natural killer cells kill?

Answer 35

Bore holes in target cells by secreting perforin, MAC forms, enzymes enter the cell through the pore and cause cell suicide

FasL of NK binds to FAS of target cell and causes the target cell to commit suicide

Question 36

What is the function of histamine?

Answer 36

Causes vasodilation, increases permeability of blood vessels, allows fluids rich in proteins to leave the capillary which causes swelling - aids blood clotting
vasodilation increases the temperature causing the metabolic rate of the cell to increase so therefore healing rate increases
Lymphocytes and phagocytes can now easily access the damaged area through the permeable blood vessels

Question 37

How does the natural killer cell know which is an infected cell?

Answer 37

A cell without the MHC 1 - a protein found in all nucleated cells