The Immune System Flashcards
What are the body’s physical barriers?
Skin, mucus, commensal bacteria.
What are the leukocyte (white blood cell) components of the immune system?
Neutrophils, monocytes, macrophages, dendritic cells, basophils, eosinophils, mast cells, B cells, T cells, NK cells.
What are the soluble (humoral) factors of the immune system?
Antibodies, complement, cytokines, acute phase proteins.
What is the difference between a monocyte and a macrophage?
Monocytes are found circulating in the blood, macrophages reside in tissue.
What is a cytokines made of?
A collection of small proteins and peptides.
What do cytokines do?
Control behaviour of cells and co-ordinate the immune system.
What are antibodies made of?
Protein.
When are antibodies produced?
They are produced in response to binding to an antigen.
What is an antigen?
Any substance which can stimulate the immune system.
What do antibodies do?
They provide defence against extracellular pathogens, viruses and toxins.
What are B cells?
They produce and secrete antibodies.
Where are B cells found?
Secondary lymphoid tissue: spleen, tonsils, lymph nodes.
Where do B cells mature?
Bone marrow.
What do T cells do?
They defend the body against intercellular pathogens.
What kind of T cells are helper T cells?
CD4+ cells.
What do CD8+ T cells do?
They are cytotoxic cells and kill virally infected body cells.
What immune system cells contain granules?
Mast cells, basophils, eosinophils and NK cells.
What do natural killer (NK) cells do?
Kill tumour cells, virally infected cells, antibody bound cells, and pathogens.
What do mast cells do?
They reside in tissue and protect mucosal surfaces.
What do basophils and eosinophils do?
Circulate in the blood, recruited to site of infection by inflammatory signals.
What immune response are basophils and eosinophils particularly associated with?
Allergic reactions.
What do mast cells, basophils and eosinophils have in common?
They release chemicals (histamine, heparin, cytokines) which result in acute inflammation. They defend the body against large pathogens that cannot be phagocytosed.
What is the complement system made up of?
~30 proteins.
What does the complement system do?
Enters virally infected tissue and become activated and enzymatically activate other complement proteins in a ‘cascade’ reaction.
What are the phagocytic cells?
Neutrophils, monocytes and macrophages.
