Immune System and the Body’s Defense

This set of flashcards covers key concepts related to the immune system and its functions, as outlined in the lecture notes.

What is the primary function of the immune system?

To provide immunity or protection from harm against infectious agents.

What are the five major categories of infectious agents?

Bacteria, viruses, fungi, protozoans, and multicellular parasites.

How do bacteria differ from eukaryotic cells?

Bacteria are single-celled prokaryotes that lack a nuclear envelope.

What are viruses composed of?

Pieces of DNA or RNA enclosed in a protein shell.

What distinguishes fungi from other pathogens?

Fungi are eukaryotic cells with a membrane and cell wall, producing spores.

What are protozoans?

Eukaryotic cells without a cell wall, often classified as parasites causing diseases like malaria.

What are prions?

Fragments of infectious proteins that cause disease in nervous tissue.

What components are considered part of the innate immune response?

Barriers like skin and mucosal membranes, along with internal nonspecific defenses.

What distinguishes innate immunity from adaptive immunity?

Innate immunity is nonspecific and acts immediately, while adaptive immunity is specific and takes days to develop.

What are cytokines?

Small proteins that regulate immune activity and act as chemical messengers.

What is the role of antibodies?

To bind to pathogens and facilitate their destruction by immune cells.

What major actions can antibodies perform?

Neutralization, agglutination, precipitation, complement activation, opsonization, and activation of NK cells.

What is the significance of memory lymphocytes in the immune system?

They provide a faster and more robust response upon re-exposure to the same antigen.

What is the difference between active and passive immunity?

Active immunity is acquired through exposure to an antigen and produces memory cells, while passive immunity involves transferring antibodies from another person without producing memory cells.