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Chapter 21: Pathogens - 3 functional characteristics of macrophages
Terms in this set (39)
Microscopic organisms that cause disease
What are pathogens?
Viruses, bacteria, fungi, parasites
What are examples of pathogens?
Provide resistance to fight infection, illness, and disease
What are body defenses?
Nonsepcific (innate) defenses, specific (adaptive) defenses
What are the two categories of defenses?
Always works the same way against any type of invading agent
What are nonspecific defenses?
Physical barriers, phagocytic cells, immunological surveillance, interferons, complement, inflammation, fever
What are the 7 types of nonspecific resistance?
Protect against specific pathogens, depends on activities of lymphocytes
What are specific defenses?
Develops after exposure to environmental hazards
When does specific resistance (immunity) develop?
Operate together to provide resistance to infection and disease
How do nonspecific and specific defenses work together in the immune system?
Physical barriers on outer layer of skin, hair, and epithelia layers of internal passageways (mucous membranes) that keep hazardous materials outside the body
What are the physical barriers of the nonspecific defenses?
Secretions that flush away materials (sweat glands, mucus), and secretions that kill or inhibit microorganisms
What are secretions that are included in the physical barrier?
Enzymes, antibodies, acidity of skin and stomach acid
What are the secretions that kill or inhibit microorganisms?
Mucus coated hairs in nose, and cilia of upper respiratory tract sweep dust and bacteria mucus toward mouth
What physical barriers are involved in the respiratory system?
Surface barriers breached by nicks or cuts - second line of defense must protect deeper tissues
When are surface barriers breached, and if they are breached what must protect underlying tissues?
What is the first lien of cellular defense?
Attack and remove dangerous microorganisms
What is the function of phagocytes?
What are the two classes of phagocytes?
Neutrophils and eosinophils
What cells makes up microphages?
Large phagocytic cells derived from monocytes
What cells make up macrophages?
Leave the bloodstream and enter peripheral tissues to fight infections
How do microphages fight against infections?
Neutrophils are abundant, mobile, and quick to attack bacteria, but die fighting them
How do neutrophils fight against infections/bacteria?
Eosinophils are less abundant and target things that are coated with antibodies
How do eosinophils fight against infections?
Engulf pathogens and destroy it with lysosomal enzymes
Activated macrophages respond to pathogens in several ways, what is the first?
Bind to pathogen so other cells can destroy it
What is the second way that activated macrophages respond to pathogens?
Destroy pathogen by releasing toxic chemicals into IF
What is the third way activated macrophages respond to pathogens?
Tumor necrosis factor, nitric oxide, peroxide
What toxic chemicals do macrophages release into the IF to kill pathogens?
If needed, Helper T cells cause release of enzymes of respiratory burst, which kill pathogens resistance to lysosomal enzymes by releasing toxic chemicals and increase pH of phagolysosome
If a pathogen is resistant to lysosomal enzymes released by the phagolysosome, what may step in and help to kill the pathogen and how?
Fix macrophages, free (wandering) macrophages
What are the 2 types of macrophages?
Also called histiocytes - stay in specific tissues or organs (dermis and bone marrow)
What is the function of fixed macrophages?
Microglia - found in central nervous system, Kupffer cells - found in liver sinusoids
What are the special histiocytes/fixed macrophages?
Travel through bloodstream
What is the function of free (wandering) macrophages?
Alveolar macrophages (phagocytic dust cells)
What is the special free macrophage?
Emigration, Chemotaxis, Adhesion
What are the 3 functional characteristics of free macrophages and microphages?
The ability to move through capillary walls
What is Emigration?
When they are attracted or repelled by chemicals in surrounding fluids (cytokine)
What is chemotaxis?
When phagocytosis begins - phagocyte attacks to target adhesion and surrounds it with a vesicle (engulfment)
What is adhesion?
Evade adherence with a capsule
How do some microorganisms evade adherence?
Marks pathogens by coating them with complement proteins or antibodies (gives macrophages something to grab onto and shows what they need to attack)
What is opsonization?
Intracellular digestion mediated by lysosomal enzymes (desirable) - Containment (less desirable) which can lead to chronicity and eventual re infection
What are the two possible outcomes following ingestion by macrophages?
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