Immune System Mechanisms and Functions

What are some ways the human body defends itself against invaders?

• Physical barriers like skin

• Defense cells like macrophages

• Weapon factories like B-cells

• All of the above

What are the three main actions of the Complement System?

• Crippling enemies, activating the immune system, and ripping holes in invaders.

• Producing antibodies, creating memory cells, and signaling for help.

• Forming physical barriers, digesting food, and regulating body temperature.

• Transporting oxygen, clotting blood, and repairing tissues.

How does the C3b protein help immune cells called phagocytes fight bacteria?

• It directly destroys the bacteria by dissolving them.

• It acts like a distress beacon, calling for more immune cells.

• It acts like a glue, making it easier for phagocytes to grab and swallow the bacteria.

• It changes the bacteria's shape, making them harmless.

What is the final result when the Membrane Attack Complex (MAC) forms on a bacterium?

• The bacterium becomes invisible to other immune cells.

• The bacterium's internal fluids spill out, causing it to die.

• The bacterium multiplies rapidly, spreading the infection.

• The bacterium changes its shape to become harmless.