Lecture 20: Host Defense System and Immunology

These flashcards cover key vocabulary related to the host defense system and immunology as outlined in the lecture notes.

First Line of Defense

Includes anatomical and chemical barriers such as skin, mucous membranes, and secretions.

Anatomical Barriers

Physical barriers that prevent infection, including skin, mucous membranes, and cilia in the respiratory tract.

Chemical Barriers

Substances that protect against infections, like lysozyme in saliva and varying pH levels.

Immunology

The study of the immune system and the body's resistance to infectious agents.

White Blood Cells (WBCs)

Cells of the immune system involved in defending the body against infections.

Phagocytosis

The process by which certain cells engulf and destroy pathogens.

Reticuloendothelial System (RES)

A network of phagocytic cells involved in immune responses, also known as the mononuclear phagocyte system (MPS).

Hematopoiesis

The production of blood cells from hematopoietic stem cells in the bone marrow.

Granulocytes

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

Agranulocytes

White blood cells with very small granules, including monocytes and lymphocytes.

Neutrophils

The most abundant type of WBC involved in phagocytosis and the first responders during inflammation.

Basophils

A type of granulocyte that releases histamine and is involved in allergic reactions.

Monocytes

Large agranulocytes that differentiate into macrophages and dendritic cells for phagocytosis.

Lymphocytes

A type of agranulocyte responsible for specific immune responses, including T cells and B cells.

Lymphatic System

A network that helps return extracellular fluids to the circulatory system and plays a role in immune surveillance.

Inflammation

A non-specific immune response characterized by redness, heat, swelling, pain, and loss of function.

Fever

An elevated body temperature that enhances immune function and is regulated by pyrogens.