Immunology Lecture 1 - Principles and Elements of Immunity

Vocabulary style practice flashcards covering fundamental terminology, cell types, tissues, and concepts from Lecture 1.

Cytokines

Soluble proteins released by interacting immune cells that act as signaling messengers to generate anti-microbial cellular responses.

Vaccination

Inoculation with a small amount of pathogen or a harmless variant of the pathogen to trigger an immune response that protects against full-blown infection.

Phagocytosis

Derived from the Greek word phagein (to devour), the process by which immune cells such as neutrophils and macrophages engulf and degrade pathogens or cellular debris.

Inflammation

A tissue reaction marked by redness, swelling, heat, and pain, which is driven by the host immune response rather than direct action by the pathogen itself.

Innate Immune System

An evolutionarily ancient defense system (approximately $1.5 \times 10^9$ years old) found in all multicellular organisms, characterized by a limited number of specificities and invariant responses upon re-encountering pathogens.

Adaptive Immune System

An evolutionary immune system that arose in jawed vertebrates approximately $5 \times 10^8$ years ago, composed of B and T lymphocytes offering vast specificity and immunological memory.

Hematopoiesis

The generation and development of all blood cell types from pluripotent hematopoietic stem cells in the adult bone marrow.

Primary Lymphoid Tissue

Anatomical sites of hematopoiesis, such as the bone marrow and thymus, where B and T lymphocytes are generated.

Secondary Lymphoid Tissues

Anatomical sites where mature immune cells accumulate and launch immune defenses, including lymph nodes, spleen, tonsils, adenoids, appendix, and Peyer's patches.

Neutrophils

Phagocytic cells stored in large reserves within the bone marrow that rapidly travel to infected tissue to engulf and kill bacteria before dying and being degraded by macrophages.

Macrophages

Phagocytic cells that respond to pathogens using cell-surface receptors to induce engulfment, degrade debris, and synthesize inflammatory cytokines.

Lymphocytes

Leukocytes derived from a common lymphoid precursor, encompassing B cells, T cells, NK cells, and innate lymphoid cells (ILCs).

Draining Lymph Node

A secondary lymphoid organ where naive lymphocytes arriving via arterial blood encounter lymph-borne pathogens delivered from infected peripheral tissue through lymphatics.

Common Myeloid Cell Precursor

A progenitor cell derived from pluripotent hematopoietic stem cells that differentiates into erythrocytes, megakaryocytes/platelets, granulocytes (neutrophils, eosinophils, basophils), monocytes, macrophages, dendritic cells, and mast cells.

Common Lymphoid Cell Precursor

A progenitor cell originating from pluripotent hematopoietic stem cells that gives rise to T-cell precursors, B cells, NK cells, and innate lymphoid cells (ILCs).