Lecture 5 and 6 Flashcards
Which leukocytes are considered the professional phagocytes?
Macrophages and neutrophils
How long do monocytes circulate in the blood stream before migrating to the tissues?
1-2 days
What is the prominent leukocyte present in acute inflammation?
Neutrophil
What is the prominent cell type present in chronic inflammation?
Macrophage
True or false: Macrophages are longer-lived than neutrophils.
TRUE
Both neutrophils and macrophages have Fc receptors and C3b receptors. What are these receptors used for?
Detecting pathogens opsonized with antibody (Fc receptor) and/or complement (C3b receptor), triggering phagocytosis.
Macrophages possess a killing molecule that neutrophils do not. Which molecule is this?
Nitric oxide (NO)
What kind of signal activates a macrophage?
Cytokine signaling
True or False: Macrophages are polymorphonuclear, like neutrophls.
FALSE
Macrophages are mononuclear.
What kinds of cells do macrophages mature from?
Monocytes circulating in the blood stream.
True or False: Unlike neutrophils, macrophages can regenerate their cellular components.
TRUE
The macrophage nucleus is not condensed like a neutrophil’s, so can still be transcribed.
What is the macrophage type that resides in the lung? (2 types)
Pulmonary alveolar macrophage (PAM)
Pulmonary intravascular macrophage (PIM)
What is the macrophage type that resides in the liver?
Kuppfer cell
What is the macrophage type that resides in the bone marrow?
Osteoclast
What is the macrophage type that resides in the brain?
Microglia
What is the macrophage type that moves freely within the peritoneal and pleural cavities?
Histiocyte
What are the main functions of resident macrophages?
Defense against pathogens
Antigen presentation
Removal of dead cells
Removal of foreign objects/debris
If a pulmonary alveolar macrophage ingests a particle too large to digest, what will it do?
Migrate out of the alveolus to the ciliary escalator, where it will be transported up the trachea and swallowed for digestion.
If a pulmonary alveolar macrophage ingests and destroys a pathogen, what will it do?
Migrate out of the alveolus and drain into a bronchial lymph node for antigen presentation to lymphocytes.
Which organ contains the only capillary bed that receives 100% of cardiac output?
Lung.
Thus, the lung is an excellent blood filtration site.
What kind of pneumonia can result from an inhaled pathogen?
Bronchial pneumonia
What kind of pneumonia can result from a pathogen circulating in the blood (i.e. septicemia)?
Interstitial pneumonia
One type of resident lung macrophage is fixed, while the other type is mobile. Which is which?
Pulmonary alveolar macrophage (PAM) - Mobile
Pulmonary interstitial macrophage (PIM) - Fixed
What will happen if the resident macrophages of the lung are overwhelmed with particulate matter?
Accumulation of particulates in the lung, resulting in decreased function and inflammation. Depeding on the particle, can result in silica lung, smoker’s lung, etc.
What will happen if the resident macrophages of the lung are overwhelmed with pathogens?
Infection
What is meant by the term “angry macrophage?”
An activated macrophage with increased killing capacity
What is CMI?
Cell mediated immunity
Immunity that does not involve antibodies. Involves phagocytic cells, cytotoxic T cells, and the release of cytokines.
How is a macrophage activated?
Cytokines
Th1 (a class of T helper cells) release interleuken 1 to activate a macrophage.
Activated macrophages are better at killing. Name some pathogens that activated macrophages are capable of killing.
(Note: on this one, I would pick one pathogen to know)
Brucella
Salmonella
Listeria
Mycobacterium
What is the role of the macrophage in initial defense against a pathogen?
Act as sentinel cells
Release pro-inflammatory cytokines
Antigen presentation to T cells
What are some functions of an activated macrophage?
Cytokine secretion
Attack and kill tumor cells
Phagocyose and kill microbes
At any one time, what percentage of circulating leukocytes are monocytes?
1-3%