Understanding Immunity and How it Fights Diseases

The video explains how vaccines help prevent diseases like smallpox and measles by building immunity. It defines immunity as the body's ability to fight infections through antibodies and cells. The immune response is triggered by antigens, which are harmful substances on pathogens. The immune system identifies and destroys these invaders. Lymphocytes, including B and T cells, play crucial roles. B cells produce antibodies, while T cells destroy pathogens. Various T cells, such as cytotoxic T cells, target dangerous cells.

Why are diseases like smallpox and measles less common today?

• Because these diseases have become less virulent

• Due to natural immunity developed over generations

• Due to the widespread use of vaccines

• Because of improved hygiene practices

What is the primary role of the immune system?

• To identify and destroy foreign invaders

• To regulate body temperature

• To produce red blood cells

• To aid in digestion

What is an antigen?

• A type of white blood cell

• A type of vaccine

• A harmful substance on the surface of pathogens

• A protein that bursts cell membranes

Where are B cells produced?

• In the spleen

• In the lymph nodes

• In the bone marrow

• In the thymus

What is the function of cytotoxic T cells?

• To produce antibodies

• To attack dangerous cells by bursting their membranes

• To circulate in the lymphatic system

• To mature in the bone marrow