Innate immunity and WBCs

Question 1

What is the innate immune system?

Answer 1

The innate immune system consists of non-specific mechanisms that are inherent to the host organism, providing immediate defense against a wide range of pathogens.

Question 2

How does the innate immune system differ from the adaptive immune system?

Answer 2

The innate immune system is non-specific and responds immediately to pathogens, while the adaptive immune system is specific and develops a targeted response over time.

Question 3

What are the key characteristics of the innate immune system?

Answer 3

Key characteristics of the innate immune system include being non-specific, rapid response, and the presence of physical barriers (like skin), phagocytic cells, and various chemical mediators.

Question 4

How do phagocytes recognize pathogens in the innate immune system?

Answer 4

Phagocytes recognize pathogens through common microbial motifs, known as pathogen-associated molecular patterns (PAMPs), which are shared by many types of microorganisms.

Question 4

Does the innate immune system require prior exposure to pathogens?

Answer 4

No, the innate immune system does not require prior exposure to pathogens; it is activated immediately upon encountering a pathogen.

Question 5

What types of defenses are included in the innate immune system?

Answer 5

Defenses in the innate immune system include physical barriers (e.g., skin), chemical barriers (e.g., antimicrobial proteins), cellular defenses (e.g., phagocytes), and inflammatory responses.

Question 6

What does it mean that the innate immune system is inherited?

Answer 6

The innate immune system is inherited, meaning it is present at birth and does not require previous exposure to pathogens to function.

Question 7

Is the innate immune system specific or non-specific?

Answer 7

The innate immune system is non-specific; it provides immediate defense against a wide range of pathogens without targeting specific ones.

Question 8

What role do phagocytes play in the innate immune system?

Answer 8

Phagocytes play a crucial role by engulfing and destroying pathogens through processes like phagocytosis, contributing to the immediate immune response.

Question 9

What are some examples of phagocytes in the innate immune system?

Answer 9

Examples of phagocytes include neutrophils, macrophages, monocytes, dendritic cells, and mast cells.

Question 10

What type of protection does the innate immune system provide?

Answer 10

The innate immune system provides nonspecific protection against foreign cells or substances without needing to recognize their specific identity.

Question 11

How does the innate immune system identify foreign invaders?

Answer 11

It recognizes general, conserved properties that mark invaders as foreign, rather than specific characteristics.

Question 12

Is the innate immune response present at birth?

Answer 12

Yes, the innate immune system is inherited and present at birth, allowing immediate defense against pathogens.

Question 13

What distinguishes the innate immune system from the adaptive immune system?

Answer 13

The innate immune system is nonspecific and reacts quickly, while the adaptive immune system is specific and develops memory over time.

Question 14

Why is it important for the innate immune system to recognise conserved properties?

Answer 14

Recognising conserved properties allows the innate immune system to respond effectively to a wide range of pathogens, providing immediate protection.

Question 15

What are PAMPs and their role in pathogen recognition?
Back:

Answer 15

PAMPs (Pathogen-Associated Molecular Patterns) are molecular signatures on pathogens that are recognized by the innate immune system to initiate a response.

Question 16

What is one of the primary functions triggered by the recognition of PAMPs?

Answer 16

The recognition of PAMPs triggers inflammation, which helps recruit immune cells to the site of infection.

Question 17

How do PAMPs influence complement activation?

Answer 17

PAMPs activate the complement system, which enhances the ability to identify bacteria, activate immune cells, and promote clearance of pathogens

Question 18

What is the significance of identifying bacteria through PAMPs?

Answer 18

Identifying bacteria through PAMPs helps activate immune cells and promotes clearance of the pathogens from the hos

Question 19

How do PAMPs affect the adaptive immune system?

Answer 19

PAMP recognition activates the adaptive immune system, leading to a more specific and long-lasting immune response against pathogens.

Question 20

What are the four steps of leukocyte extravasation?

Answer 20

Chemoattraction
Rolling adhesion
Tight adhesion
Endothelial transmigration via pseudopodia

Question 21

What occurs during the chemoattraction step of leukocyte extravasation?

Answer 21

TLR activation leads to the release of cytokines and chemokines, which attract leukocytes to the site of infection.

Question 22

What is the role of carbohydrate ligands in the rolling adhesion step?

Answer 22

Carbohydrate ligands on leukocytes bind with slight affinity to selectin molecules on endothelial cells, facilitating rolling along the vessel wall.

Question 23

What activates integrin molecules during the tight adhesion step?

Answer 23

Chemokines produced by macrophages activate integrin molecules on leukocytes, leading to a stronger adhesion to the endothelial cells.

Question 24

How do leukocytes undergo endothelial transmigration?

Answer 24

Leukocytes use pseudopodia to squeeze through the gaps in endothelial cells, allowing them to exit the bloodstream and enter the tissue at the site of infection.

Question 25

What is the first step of leukocyte extravasation?

Answer 25

Chemoattraction: TLR activation leads to cytokine and chemokine release. Chemokines attract leukocytes to the site of infection or injury.

Question 26

Describe the second step of leukocyte extravasation.

Answer 26

Rolling Adhesion: Carbohydrate ligands on leukocytes bind with slight affinity to selectin molecules on endothelial cells, causing the leukocytes to roll along the vessel wall.

Question 27

What occurs during the third step of leukocyte extravasation?

Answer 27

Tight Adhesion: Chemokines from macrophages activate integrin molecules on leukocytes, increasing their affinity for adhesion molecules on endothelial cells, allowing firm attachment.

Question 28

Explain the final step of leukocyte extravasation.

Answer 28

Endothelial Transmigration: Leukocytes use pseudopodia to migrate through the endothelial cell layer, exiting the bloodstream to enter tissues where they are needed.

Question 29

What are selectins, and what role do they play in extravasation

Answer 29

Selectins: Adhesion molecules on endothelial cells (e.g., P-selectin, E-selectin) that bind to carbohydrates on leukocytes, facilitating their initial rolling adhesion.

Question 30

Name two types of endothelial selectins involved in leukocyte recruitment.

Answer 30

P-selectin and E-selectin: Both are types of selectins that bind carbohydrates on leukocytes, helping them adhere to the endothelium during extravasation.

Question 31

Give an example of an integrin and its function.

Answer 31

LFA-1 is an integrin that binds to Cell-Adhesion Molecules (CAMs) like ICAM on endothelial cells to promote tight adhesion.

Question 31

What are integrins, and how do they function in extravasation?

Answer 31

Integrins are Adhesion molecules found on leukocytes that facilitate firm adhesion to endothelial cells. They interact with cell-adhesion molecules (CAMs) on the endothelium.

Question 32

How do selectins and integrins work together during extravasation?

Answer 32

Selectins mediate the initial rolling adhesion of leukocytes, while integrins enable tighter adhesion to the endothelial cells, allowing for transmigration.

Question 33

What role do chemokines play in cell recruitment?

Answer 33

Chemokines influence the migration of immune cells by attracting them to specific tissues.

Question 33

How do different chemokines affect cell recruitment?

Answer 33

Different chemokines recruit different types of immune cells to various tissues based on the specific signals they provide.

Question 34

What is the significance of different combinations of selectins in cell recruitment?

Answer 34

Different combinations of selectins on endothelial cells facilitate the selective recruitment of specific immune cells to sites of inflammation or infection.

Question 35

Why is selective recruitment important in the immune response?

Answer 35

Selective recruitment ensures that the appropriate immune cells are directed to the right tissues at the right time, enhancing the effectiveness of the immune response.

Question 36

What additional role do PAMPs play beyond activating phagocytes?

Answer 36

PAMPs also activate the complement system.

Question 37

What are the three main roles of the complement system

Answer 37

Inflammation
Cell lysis
Opsonization

Question 38

How do PAMPs contribute to inflammation?

Answer 38

PAMPs activate the complement system, which triggers inflammatory responses to recruit immune cells to the site of infection.

Question 39

What is cell lysis in the context of the complement system?

Answer 39

Cell lysis refers to the destruction of pathogen cell membranes, leading to the death of the invader.

Question 40

How does opsonisation enhance the immune response?

Answer 40

Opsonisation marks pathogens for destruction by phagocytes, making it easier for them to recognize and engulf the invaders.

Question 41

What initiates the immune response?

Answer 41

It all begins with recognition of pathogens via PAMPs.

Question 42

What do PAMPs do in the immune system?

Answer 42

PAMPs serve as flags on pathogens, enabling their recognition by the immune system

Question 43

How do PAMPs trigger an immune response?

Answer 43

PAMPs trigger inflammation and cause cell recruitment to the site of infection.

Question 44

What is the role of PAMPs in the complement activation?

Answer 44

PAMPs activate the complement system, which helps identify bacteria, activate immune cells, and promote clearance.

Question 45

How do PAMPs affect the adaptive immune system?

Answer 45

PAMPs activate the adaptive immune system, enabling a specific response to pathogens.

Question 46

What is complement?

Answer 46

Complement is a system of more than 30 proteins found in plasma and on cell surfaces.

Question 47

What type of biochemical processes does the complement system involve?

Answer 47

The complement system involves a series of proteolytic cascades.

Question 48

How many main pathways activate the complement system?

Answer 48

There are three main pathways of activation for the complement system.

Question 49

What are the three main pathways of complement activation?

Answer 49

Classical
2. Alternative
3. Lectin

Question 50

How do pathogens interact with the immune system?

Answer 50

The breakdown of pathogens generates numerous antigens.

Question 51

What do the antigens generated from pathogens represent?

Answer 51

Antigens represent fragments of various proteins expressed by the pathogen.

Question 52

Where can antigens be presented?

Answer 52

Antigens can be presented on phagocytic cells or released into the body.

Question 53

How are antigens related to the adaptive immune system?

Answer 53

Antigens can be recognized by cells in the adaptive immune system.