The exaggerated response of the immune system to certain antigens present in the environment (like pollen or mites) is called:

[Human-Health-and-Disease] [class-xii ]

• Auto immunity
• Active immunity
• Allergy
• Anamnestic response
Correct Option: C  [ Allergy ]

Remark: The exaggerated response of the immune system to certain antigens present in the environment is called allergy.

The substances that provoke an allergic immune response are called:

[Human-Health-and-Disease] [class-xii ]

• Antitoxins
• Allergens
• Pathogens
• Interferons
Correct Option: B  [ Allergens ]

Remark: The substances to which such an immune response is produced are called allergens.

What type of antibodies are produced in response to allergens?

[Human-Health-and-Disease] [class-xii ]

• IgM
• IgG
• IgA
• IgE
Correct Option: D  [ IgE ]

Remark: The antibodies produced to these (allergens) are of IgE type.

Allergy symptoms arise due to the release of chemicals like histamine and serotonin from which type of cells?

[Human-Health-and-Disease] [class-xii ]

• B-lymphocytes
• Mast cells
• Macrophages
• Natural killer cells
Correct Option: B  [ Mast cells ]

Remark: Allergy is due to the release of chemicals like histamine and serotonin from the mast cells.

Which common auto-immune disease is mentioned in the sources?

[Human-Health-and-Disease] [class-xii ]

• Typhoid fever
• Rheumatoid arthritis
• Pneumonia
• Common cold
Correct Option: B  [ Rheumatoid arthritis ]

Remark: Rheumatoid arthritis which affects many people in our society is an auto-immune disease.

The human immune system recognizes foreign antigens, responds to them, and performs which critical action characteristic of acquired immunity?

[Human-Health-and-Disease] [class-xii ]

• Attacking self-cells
• Phagocytosis
• Remembers them
• Releasing histamine
Correct Option: C  [ Remembers them ]

Remark: The immune system is unique in the sense that it recognises foreign antigens, responds to these and remembers them.

Which of the following is considered a primary lymphoid organ?

[Human-Health-and-Disease] [class-xii ]

• Spleen
• Lymph nodes
• Bone marrow
• Tonsils
Correct Option: C  [ Bone marrow ]

Remark: The primary lymphoid organs are bone marrow and thymus.

What is the function of primary lymphoid organs (bone marrow and thymus)?

[Human-Health-and-Disease] [class-xii ]

• Filtering blood of micro-organisms
• Sites for proliferation of effector cells
• Origin and maturation of lymphocytes into antigen-sensitive lymphocytes
• Trapping antigens from tissue fluid
Correct Option: C  [ Origin and maturation of lymphocytes into antigen-sensitive lymphocytes ]

Remark: Primary lymphoid organs are where immature lymphocytes differentiate into antigen-sensitive lymphocytes.

Which of the following is NOT a secondary lymphoid organ?

[Human-Health-and-Disease] [class-xii ]

• Spleen
• Peyer's patches of small intestine
• Thymus
• Appendix
Correct Option: C  [ Thymus ]

Remark: Thymus is a primary lymphoid organ; spleen, lymph nodes, tonsils, Peyer’s patches, and appendix are secondary lymphoid organs.

The spleen acts as a filter of the blood by trapping micro-organisms and also has a large reservoir of:

[Human-Health-and-Disease] [class-xii ]

• Lymphocytes
• Erythrocytes
• Platelets
• Pathogens
Correct Option: B  [ Erythrocytes ]

Remark: Spleen acts as a filter of the blood and also has a large reservoir of erythrocytes.