Human Defense Systems: Physical and Chemical Barriers and the Specific Immune System

The video tutorial explains how the human body defends against pathogens through physical barriers like skin and mucus, chemical defenses such as lysozymes and stomach acid, and the specific immune system involving lymphocytes and antibodies. It also covers the secondary immune response, highlighting the role of memory lymphocytes in providing immunity.

What are the three main ways our bodies defend against pathogens?

• Diet, exercise, and sleep

• Meditation, yoga, and relaxation

• Antibiotics, vaccines, and hygiene

• Physical barriers, chemical defenses, and the specific immune system

How does the skin act as a physical barrier against pathogens?

• By producing antibodies

• By secreting enzymes

• By being a thick layer that prevents entry unless broken

• By increasing body temperature

What role does mucus play in defending the body?

• It produces antibodies

• It digests pathogens

• It increases blood flow

• It traps dust and pathogens, preventing them from entering the body

What is the function of ciliated cells in the respiratory system?

• To produce antibodies

• To move mucus and trapped particles out of the airways

• To secrete enzymes

• To increase oxygen absorption

How do lysozymes contribute to the body's chemical defenses?

• By trapping pathogens in mucus

• By increasing the body's temperature

• By breaking down the cell walls of some bacteria

• By producing antibodies

What is the role of hydrochloric acid in the stomach?

• To digest food

• To lower pH and destroy most pathogens

• To neutralize stomach enzymes

• To increase nutrient absorption

What are lymphocytes and what is their primary function?

• A type of red blood cell that carries oxygen

• A type of white blood cell that produces antibodies

• A type of cell that digests food

• A type of cell that secretes mucus

What is an antigen?

• A type of white blood cell

• A chemical that neutralizes stomach acid

• A protein on the surface of pathogens that triggers an immune response

• A hormone that regulates blood sugar

How do memory lymphocytes contribute to the secondary immune response?

• By remembering past infections and responding faster

• By increasing body temperature

• By producing more mucus

• By producing more stomach acid

What is the primary difference between the primary and secondary immune responses?

• The secondary response is faster and more effective

• The secondary response is slower

• The primary response is faster

• The primary response produces more antibodies