THIRD LINE OF DEFENCE- ADAPTIVE IMMUNITY

Question 1

What is the primary function of the third line of defense in the immune system?

Answer 1

Targets specific pathogens
Develops and adapts in response to specific pathogens that we encounter
Produces memory cells

Question 2

Which cells produce antibodies in response to antigens?

Answer 2

B lymphocytes

Question 3

What are lymphocytes?

Answer 3

• white blood cells that is found in the blood and lymphoid tissue

Question 4

What is the antibody mediated response/humoral response?

Answer 4

The humoral response is an immune response activated by B lymphocytes, which can differentiate into plasma cells and memory B cells.

Question 5

Where are B cells produced and where do they accumulate?

Answer 5

B cells are produced in the bone marrow and accumulate in lymphoid tissues.

Question 6

What happens to B cells upon exposure to an antigen?

Answer 6

Upon exposure to an antigen, B cells are activated and can differentiate into plasma cells or memory B cells.

Question 7

What are the functions of plasma cells?

Answer 7

• production of antibodies that can bind to specifc antigens on pathogens or foreign substances

Question 8

What is the structure and function of antibodies?

Answer 8

• Antibodies are Y-shaped proteins that bind to specific antigens, forming an antigen-antibody complex. They can neutralize pathogens, enhance phagocytosis through precipitation and agglutination, and activate the complement system.

Question 9

What is the role of memory B cells?

Answer 9

• Memory B cells have long-term memory of a specific antigen. They enable a faster and stronger defense upon reexposure to the antigen, resulting in less severe symptoms.
• provide long-term protection against re-infection.

Question 10

True or False: B cells primarily reside in the thymus gland.

Answer 10

false- B cells are found in the lymphoid tissues

Question 11

What are the main types of T lymphocytes?

Answer 11

Cytotoxic (killer T) cells, memory T cells, supressor cells, helper T cells

Question 12

Where are T cells made and where do they mature?

Answer 12

• made in bone marrow and mature in thymus gland

Question 13

What happens to T cells once they are matured?

Answer 13

Once matured, T cells are released into the blood and continuously circulate, seeking out infected cells.

Question 14

What is the function of cytotoxic (killer) T cells?

Answer 14

T cells seek out and kill foreign infected cells by secreting toxins that prevent pathogen replication and destroy the infected cells.

Question 15

What is the role of helper T cells?

Answer 15

• Helper T cells promote the activities of other immune responses by secreting cytokines. They enhance the activity of phagocytes, promote inflammation, stimulate the production of killer T cells, and stimulate the differentiation of B cells into plasma and memory B cells.

Question 16

What is the function of suppressor T cells?

Answer 16

Suppressor T cells turn off the immune response after the pathogen has been removed and destroyed,

Question 17

What is the role of memory T cells?

Answer 17

Memory T cells provide long-term defense and can quickly recognize and respond to specific antigens upon reexposure.

Question 18

What is cell mediated response?

Answer 18

• When T lymphocytes target and destroy infected host cells along with the pathogens inside them
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Question 19

What is cell mediated response effective against?

Answer 19

• intracellular pathogens
  protozoa, bacteria, viruses
• tapeworms
• cancer cells

Question 20

What is the role of antigen-presenting cells (such as macrophages) in the cell-mediated response?

Answer 20

Antigen-presenting cells engulf foreign material and display the antigen on their surface using MHC II molecules.

Question 21

What happens when an antigen-presenting macrophage encounters helper T cells in the lymph nodes?

Answer 21

The antigen-presenting macrophage, recognized by helper T cells through their receptors, triggers the release of cytokines by the helper T cells.

Question 22

What is the outcome of the activation of helper T cells?

Answer 22

Activation of helper T cells leads to the production of cytokines and the activation of killer T cells and memory T cells specific to the antige

Question 23

Where do killer T cells migrate to in the cell-mediated response?

Answer 23

Killer T cells migrate to the site of infection where their receptors bind with the antigen.

Question 24

What do killer T cells release, and what is the result?

Answer 24

Killer T cells release toxic chemicals that cause cell death, killing the infected cell and the pathogen.

Question 25

How does the release of chemicals by killer T cells contribute to inflammation and phagocytosis?

Answer 25

The released chemicals may increase inflammation, attracting more macrophages and enhancing phagocytosis.

Question 26

What is the role of memory T cells in the cell-mediated response?

Answer 26

Some activated T cells differentiate into memory T cells, which remain in the body. Upon re-exposure to the same antigen, memory T cells can quickly respond and produce killer T cells, preventing the person from experiencing the same symptoms again.

Question 27

Which type of immune response is more effective against intracellular pathogens?

Answer 27

The cell-mediated response.

Question 28

Which type of immune response is primarily effective against pathogens present in body fluids or extracellular spaces?

Answer 28

The humoral response.