Innate Immune System

Question 1

What are the four cells part of the innate immune system?

Answer 1

• Neutrophil
• Basophil
• Eosinophil
• Monocyte

Question 2

What is the common ancestor of the innate immune system cells?

Answer 2

Myeloid progenitor

Question 3

What is a neutrophil?

Answer 3

Most common type of granulocyte and phagocytic WBC that fights infection and heals injuries.

Question 4

What are granulocytes?

Answer 4

A type of WBC that contain granules filled with enzymes

Question 5

What do neutrophils look like under the microscope?

Answer 5

Pink or orange cells with a segmented nucleus and cytoplasmic granules

Question 6

What is a basophil?

Answer 6

Largest but least common granulocyte WBC that fights infection and allergens

Question 7

What do basophils look like under the microscope?

Answer 7

Lots of little purple dots clumped together with two purple lobes sometimes visible

Question 8

What is a eosinophil?

Answer 8

A type of granulocyte WBC that fights infections, allergens and parasites

Question 9

What do eosinophils look like under the microscope?

Answer 9

Two raindrop shaped lobed nucleus connected by a thread with prominent larger granules

Question 10

What is a monocyte?

Answer 10

A type of phagocytic WBC which becomes a macrophage or a dendrite cell

Question 11

What do monocytes look like under the microscope?

Answer 11

Much larger with a kidney bean shaped nucleus

Question 12

What are the five key characteristics of the innate immune system?

Answer 12

• Speed, early and rapid
• Duration, short lived
• Repetitive, responds the same way
• Interactive with other cells
• Non reactive to the host

Question 13

What is the innate immune response?

Answer 13

The body’s first line of defence which is non-specific

Question 14

When does the innate immune response usually occur?

Answer 14

Within hours of exposure

Question 15

When does the adaptive immunity response usually occur?

Answer 15

1-7 days

Question 16

What does PRRs stand for?

Answer 16

Pattern recognition receptors

Question 17

Where can PRRs be found?

Answer 17

Epithelial cells, endothelial cells and resident immune cells

Question 18

What are endothelial cells?

Answer 18

A single cell layer that lines all blood vessels and regulates exchanges between the bloodstream and the surrounding tissues

Question 19

What are PRRs?

Answer 19

Receptors that can detect patterns on microbes and damaged cells

Question 20

What does PAMPs stand for?

Answer 20

Pathogen associated molecular patterns

Question 21

What are PAMPs?

Answer 21

Microbial patterns

Question 22

What does DAMPs stand for?

Answer 22

Damage associated molecular patters

Question 23

What are DAMPs?

Answer 23

Patterns on damaged or necrotic cells

Question 24

What happens when PAMPs or DAMPs bind to PRRs?

Answer 24

Triggers a cascade of events such as the release of soluble mediators and recruitment of innate immune cells

Question 25

What does TLRs stand for?

Answer 25

Toll like receptors

Question 26

What are TLRs?

Answer 26

A specialised type of PRRs

Question 27

Where can TLRs be found?

Answer 27

On the cell surface where they recognise extracellular microbes or in endosomes where they recognise ingested microbes

Question 28

What are endosomes?

Answer 28

Organelles that sort and transport proteins and lipids within cells

Question 29

What happens when PAMPs bind to TLR?

Answer 29

It activates transcription factors that stimulate expression genes encoding cytokines, enzymes and other proteins

Question 30

What are cytokines?

Answer 30

Proteins that act as chemical messengers to signal and coordinate the immune system

Question 31

Where can PRRs be found?

Answer 31

- Cell surfaces - Endosomal membranes - Cytosol

Question 32

Why are histamines and inflammatory cytokines important?

Answer 32

They dilate blood vessels which allow more blood flow to the area causing redness and more fluid to come in which causes swelling

Question 33

Why are adhesion molecules important during inflammation?

Answer 33

They act as a speed bump slowing down WBC allowing them to adhere to the blood vessel wall and migrate into inflamed tissue

Question 34

What occurs when PAMPs bind to PRRs on neutrophils and macrophages?

Answer 34

It triggers phagocytosis and production of soluble mediators

Question 35

What is a phagosome?

Answer 35

A vesicle formed around a particle engulfed by phagocytosis

Question 36

What are phagolysosomes?

Answer 36

Phagosomes which have fused with lysosomes to kill the microbes

Question 37

What is lysosome?

Answer 37

An organelle that contains enzymes and toxic substances such as nitric oxide that break down waste and other materials

Question 38

What are the four major cytokines that will trigger inflammation?

Answer 38

TNF, IL-1, IL-6 and IL-12

Question 39

What happens if the organism survives the innate mechanisms of phagocytosis?

Answer 39

The phagocytes have to be activated by T cells to activate additional killing mechanisms

Question 40

What does APC stand for?

Answer 40

Antigen presenting cells

Question 41

What are APCs?

Answer 41

Cells that are specialised at capturing microbes and other antigens

Question 42

What are antigens?

Answer 42

Substances that trigger the body's immune response

Question 43

What are antibodies

Answer 43

Are Y shaped proteins that recognise antigens on the surface of microbes

Question 44

What are dendritic cells?

Answer 44

Is a type of phagocytic and antigen presenting cells that boost immune responses by capturing microbes and showing antigens on its surface to other cells of the immune system

Question 45

What are dendritic cells responsible for?

Answer 45

Initiating adaptive immune responses they are the ultimate bridge between innate and adaptive immunity