GCSE Biology - Immune System (Defences Against Pathogens) #38

The video explains the human body's defense system against pathogens, highlighting the physical and chemical barriers like skin, mucus, and stomach acid that prevent pathogen entry. It also covers the immune system's role, focusing on white blood cells and their functions, including phagocytosis, antitoxin production, and antibody creation. The video clarifies the difference between antigens and antibodies and describes how the immune system remembers pathogens to provide immunity.

What is the primary function of the skin in the body's defense system?

• To digest food

• To act as a physical barrier

• To circulate blood

• To produce antibodies

How does the stomach contribute to the body's defense against pathogens?

• By producing antibodies

• By increasing blood flow

• By secreting mucus

• By producing hydrochloric acid

Which cells are primarily responsible for phagocytosis in the immune system?

• Red blood cells

• White blood cells

• Platelets

• Nerve cells

What is the role of antitoxins produced by white blood cells?

• To bind and neutralize toxins

• To increase blood pressure

• To transport oxygen

• To digest food

What is the relationship between antibodies and antigens?

• Antibodies are produced by antigens

• Antigens destroy antibodies

• Antibodies bind to antigens to signal their destruction

• Antigens are a type of antibody