Lecture #2

These flashcards cover the key concepts, cell types, functions, and processes involved in the immune system as discussed in the lecture.

What percentage of white blood cells are neutrophils in circulation?

55 - 90% of WBCs.

What is the primary function of eosinophils?

Killing extracellular parasites.

Where do T lymphocytes mature?

In the thymus.

What are the primary lymphoid organs for B cell maturation in mammals?

Bone marrow.

What happens when a mature, naïve B or T cell meets its antigen?

Clonal expansion occurs, resulting in mitosis to make copies.

What are the major secondary lymphoid organs?

Lymph nodes, spleen, and some Peyer’s patches.

What is the function of endothelial cells in immune responses?

They regulate leukocytic traffic and facilitate binding of neutrophils to exit the bloodstream.

What is the lifespan of a neutrophil in circulation?

8 to 10 hours.

What do basophils release that is important in allergy and parasitic infections?

Inflammatory mediators such as histamine.

What is the role of macrophages in the immune response?

Phagocytosis, presenting antigens on MHC II, and secreting cytokines.