Anatomy - Positive & Negative Selection for Lymphocytes

The video tutorial explains the concepts of antigens and immunogens in the immune system, highlighting the difference between self and foreign antigens and their role in immune tolerance. It discusses how abnormal cells, such as cancerous or virally infected cells, trigger immune responses. The tutorial differentiates between antigens and immunogens, emphasizing that not all antigens induce an immune response. It also covers the formation and selection of lymphocytes, detailing the processes of positive and negative selection to ensure immune cells target foreign antigens while avoiding self-antigens.

What is the primary role of an antigen in the immune system?

• To act as a barrier against pathogens

• To produce antibodies

• To bind with lymphocytes and potentially induce an immune response

• To destroy foreign cells

How does a self-antigen signal to the immune system?

• It triggers the production of antibodies

• It marks the cell for destruction

• It signals that the cell is part of the body and should not be attacked

• It indicates the cell is foreign and should be attacked

What happens when a cell displays a foreign antigen?

• It is ignored by the immune system

• It is recognized as part of the body

• It triggers an immune response

• It becomes a self-antigen

What is the significance of a normal self-antigen?

• It signals the immune system to attack

• It indicates the cell is foreign

• It shows the cell is healthy and part of the body

• It triggers an immune response

What distinguishes an immunogen from an antigen?

• An immunogen is a foreign cell

• An immunogen is a type of antibody

• An immunogen always induces an immune response

• An immunogen is a cell that cannot be attacked

Where do B lymphocytes mature?

• In the lymph nodes

• In the red bone marrow

• In the spleen

• In the thymus

What is the purpose of positive selection in lymphocyte formation?

• To ensure lymphocytes bind to self-antigens

• To ensure lymphocytes bind to abnormal or foreign antigens

• To destroy all lymphocytes

• To produce more lymphocytes

What is the role of negative selection in lymphocyte formation?

• To ensure lymphocytes do not bind to self-antigens

• To destroy foreign cells

• To produce antibodies

• To ensure lymphocytes bind to self-antigens

What happens to lymphocytes that bind to normal self-antigens during selection?

• They are kept for future use

• They are destroyed

• They are converted into antibodies

• They are ignored

What is the outcome for lymphocytes that do not bind to abnormal antigens during positive selection?

• They are converted into antibodies

• They are ignored

• They are destroyed

• They are kept for future use