The video explains the immune system's role in protecting the body from harmful antigens and pathogens. It describes two types of immunity: natural and acquired, highlighting the functions of lymphocytes, including B cells and T cells. The video also discusses how the immune system can overreact, causing allergies, and explains the body's response to flu, including fever as a defense mechanism.

What are the two main functions of the immune system?

• To digest food and absorb nutrients

• To control body temperature and blood pressure

• To prevent diseases from entering the body and attack those that do

• To produce hormones and regulate metabolism

Which of the following is an example of natural immunity?

• Memory cells recognizing antigens

• Skin blocking pathogens

• Antibody production by B cells

• Vaccination

What is the role of B cells in the immune system?

• To produce hormones

• To release antibodies that attack antigens

• To regulate body temperature

• To destroy infected body cells

How does the immune system respond to non-harmful antigens in allergies?

• By producing antibodies

• By ignoring them

• By attacking them, causing symptoms like sneezing

• By strengthening the skin barrier

What causes a fever during an infection?

• An increase in blood pressure

• A malfunction in the digestive system

• The immune system's response to create a harsh environment for pathogens

• The actual infection itself