9 Host Defenses and Microbial Disease Free Online FlashCards

What is a key feature of innate immunity?

Innate immunity responds rapidly to broad features shared by microbes.

How do physical and chemical barriers defend the body?

Skin, mucus, cilia, and antimicrobial substances make it harder for microbes to enter or establish themselves.

What is phagocytosis?

Phagocytosis is the engulfment and destruction of microbes by cells such as neutrophils and macrophages.

Name three ways the complement system helps defend against microbes.

Complement proteins can coat microbes to aid engulfment, promote inflammation, and damage some microbial membranes.

How do interferons and natural killer cells help control viral infection?

Interferons help limit viral replication, while natural killer cells can kill some infected cells.

How can dendritic cells help activate adaptive immunity?

Dendritic cells take up microbial material and present pieces of it to T cells, helping initiate a targeted response.

What is an antigen?

An antigen is a molecule or molecular part recognized by the immune system.

What do plasma cells do, and how can their antibodies help?

Activated B cells can become plasma cells that secrete antibodies, which may neutralize pathogens or mark them for destruction.

What is the main role of helper T cells?

Helper T cells coordinate immune responses by signaling to other immune cells.

How do cytotoxic T cells help control intracellular infections?

Cytotoxic T cells recognize and kill host cells displaying certain microbial antigens, helping control infections inside cells.

How do memory B and T cells affect later exposure to an antigen?

Memory B and T cells can support a faster, stronger response when the same or a sufficiently similar antigen is encountered again.

How can a microbial capsule help a pathogen evade immunity?

A capsule can make a microbe harder for phagocytes to recognize and capture.