Immunology Quiz: Immune System Functions

The immune system is a complex network of cells, tissues, and organs that work together to protect the body from harmful substances, such as bacteria, viruses, fungi, and parasites.

The innate immune system is the body's first line of defense against infection. It is non-specific, meaning it attacks any foreign substance that enters the body. This system is present from birth.

The acquired or adaptive immune system is the body's second line of defense. It is specific, meaning it targets specific pathogens that have already entered the body. This system learns and remembers pathogens, so it can respond more effectively next time.

Inflammation is the body's natural response to injury or infection. It brings immune cells to the site of injury or infection to fight off invaders and begin the healing process. The four cardinal signs of inflammation are redness, swelling, heat, and pain.

Fever is a temporary increase in body temperature that is caused by pyrogens. Pyrogens are substances that trigger the release of prostaglandins, which reset the body's set temperature.

Phagocytosis is the process by which certain cells in the immune system, called phagocytes, engulf and destroy pathogens. This is a key part of the innate immune response.

Natural killer (NK) cells are a type of white blood cell that kill cells that are infected with viruses or have become cancerous. They are part of the innate immune system and are important for controlling viral infections and preventing the spread of cancer.

The complement system is a collection of proteins that work together to destroy pathogens and help other immune cells. It is part of the innate immune system. The cascade of protein activation creates a chain reaction that ultimately damages the pathogen.

A series of reactions where each component activates the next, leading to the formation of activated complement proteins.

Activated complement proteins can puncture bacterial cell membranes, causing the bacteria to burst.

Complement proteins attached to bacteria act as flags, signaling macrophages to engulf and destroy the bacteria.

Complement proteins attract immune cells to infected areas, promoting inflammation.

A chemical released by mast cells, basophils and platelets, triggering vasodilation, increased vascular permeability, and other effects.

A natural defense mechanism that involves cells like macrophages, neutrophils, and dendritic cells engulfing and destroying entire cells, such as bacteria or viruses. It's the first line of defense against pathogens.

Molecules found on pathogens that are recognized by pattern recognition receptors (PRRs) on immune cells, triggering phagocytosis.

Receptors on immune cells that recognize and bind to PAMPs, initiating phagocytosis and other immune responses.

Antigen-presenting molecules found on cells that display fragments of pathogens or other antigens to other cells of the immune system, especially T cells.

A type of lymphocyte that plays a critical role in innate immunity by targeting cells that lack MHC1 or are displaying PAMPs, potentially indicating infection or cancer.

Proteins released by natural killer cells that create pores in target cells, allowing granzymes to enter and induce apoptosis.

Enzymes released by natural killer cells that enter target cells through perforin-induced channels and trigger programmed cell death (apoptosis).

Programmed cell death, where a cell self-destructs in a controlled manner, removing potentially dangerous or infected cells.

Polypeptides derived from plasma proteins that cause vasodilation, increase vascular permeability, stimulate pain receptors, and attract neutrophils.

A protein produced by most cells that interferes with viral production and infection.

A group of lipids produced by mast cells that cause smooth muscle relaxation and vasodilation, increase vascular permeability, and stimulate pain receptors.

A group of lipids, primarily produced by mast cells and basophils, that cause prolonged smooth muscle contraction (especially in the lung bronchioles), increase vascular permeability, and attract neutrophils and eosinophils.

Chemicals released by neutrophils, monocytes, and other cells that stimulate fever production.

A slow but very powerful immune response that is specific to the pathogen and has memory.

A complex immune response that includes a humoral response (mediated by B lymphocytes and antibodies) and a cell-mediated response (mediated by T lymphocytes).