Chapter 12: Host Defenses Innate Immunity- Part 2 Flashcards
Events of phagocytosis
- Chemotaxis
- Ingestion
- Phagolysosome formation
- Destruction
- Excretion
Phagocytes have ______ ______ (___) that will recognize antigen receptors (PAMPS)
Specific receptors (PRR)(pattern recognition receptors)
Chemotaxis
Phagocytes migrate into a region of inflammation with a deliberate sense of direction, attracted by a gradient of stimulant products from the parasite and host tissue at the site of injury
PAMPS
Pathogen associated molecular patterns
Ingestion
Phagocytes use pattern recognition to identify and stick to foreign cells, extends pseudo-pods that enclose the cells in a pocket and internalize them
-Also secretes more cytokines
Phagolysosome formation
Lysosomes migrate to the the scene of the phagosome and fuse with it to form a phagolysosome. Granules containing antimicrobial chemicals are released into the phagolysosome, forming a potent brew designed to poison and then dismantle the ingested material
Destruction
Destructive chemicals await the microbes in the phagolysosome
-Many proteins and enzymes help to finish the job
Elimination
The small bits of undigestible debris are released from the macrophage by exocytosis
Factors that elicit inflammation
- Trauma from infection
- Tissue injury or necrosis die to physical or chemical agents
- Specific immune reactions`
Diapedesis
The migration of WBCs out of blood vessels into tissues
WBCs are actively ________ and readily change _______
Motile
Shape
How is diapedesis possible?
Endothelial cells lining venules contain complex adhesive receptors that capture WBCs and transport them into intracellular spaces
Chemotaxis (in terms with diapedesis)
Migration of cells in response to a specific chemical stimulus
-Cells swarm from many compartments to the site of infection and remain there to perform general and specific immune functions
Both diapedesis and chemotaxis are essential for…
The intercommunication and deployment of cells required for immune reactions
During inflammation, WBCs…
Start to roll along slowly instead of just flowing by
Body temperature is maintained at what temperature and by what organ?
37° celsius
(98.6° F)
Hypothalamus
Low grade fever
37.7-38.3° C
100-101° F
High fever
40.0-41.4° C
104-106°F
Pyrogens
Substances that reset the hypothalamic thermostat to a higher setting(fever causing)
What substances can also stimulate fever?
Lipopolysaccharides
Benefits of fever
- Inhibits multiplication of temperature sensitive microorganisms such as the poliovirus
- Impedes nutrition of bacteria by reducing the availability of iron
- Increases metabolism and stimulates immune reactions and naturally protective physiological processes
What does a fever speed up?
Hematopoiesis, phagocytosis, and specific immune reactions
Antimicrobial proteins (second-line defenses)
Interferon
Complement proteins
Iron binding proteins
Antimicrobial peptides
Interferon
Chemical help signal
Important first stem in an antiviral response
