1 Host Defense and Immune Cells

These flashcards provide key vocabulary and concepts related to host defense mechanisms and immune cells as covered in the lecture.

Pathogen

An organism that causes disease, needing several steps to successfully infect a host.

Lines of Defense

The body's three mechanisms for defending against foreign invaders: natural barriers, innate immunity, and adaptive immunity.

Natural Barriers

The first line of defense, consisting of physical structures like skin and mucus that limit entry and colonization by pathogens.

Innate Immunity

The second line of defense that provides a rapid, nonspecific response to eliminate microbes and activate the adaptive immune response.

Adaptive Immunity

The third line of defense characterized by a slower, specific response to pathogens involving recognition of antigens and establishment of memory.

Leukocytes

White blood cells responsible for fighting infection, including granulocytes and agranulocytes.

Hematopoiesis

The process of blood cell production from stem cells in the red bone marrow.

Phagocytosis

The process by which certain cells, like neutrophils and macrophages, engulf and destroy harmful pathogens.

Antigens

Molecules on pathogens that are recognized by the immune system, triggering an adaptive immune response.

PAMPs (Pathogen-Associated Molecular Patterns)

Molecules found on pathogens recognized by the immune system to initiate an innate immune response.

Cytotoxic T Cells

A type of lymphocyte involved in directly attacking and destroying infected or cancerous cells.

Helper T Cells

Lymphocytes that assist in activating and regulating immune responses.

Natural Killer (NK) Cells

Innate immune cells that provide rapid responses to viral-infected cells and tumor formation.

Macrophages

Large phagocytic cells derived from monocytes that can also present antigens to T cells.

Granulocytes

A category of white blood cells that contain granules in their cytoplasm, including neutrophils, basophils, and eosinophils.