Ch.16: Innate Immunity Flashcards
5 Characteristics of innate immunity:
present at birth always present and provide rapid responses nonspecific first line of defense Second line of defense
First line of defense involves:
- intact skin and mucus membranes
- normal microbiota
Second line of defense involves:
phagocytes
inflammation
fever
antimicrobial substances
enzymes that degrade peptidoglycan (more effective against gram positives), FOUND IN TEARS SALIVA BLOOD AND PHAGOCYTES
LYSOZYME
breaks down hydrogen peroxide to produce reactive oxygen, which damages cells including bacterial cells. FOUND IN SALIVA, BODY TISSUES AND PHAGOCYTES
peroxidase
How does normal microbial flora on the body protect from disease?
competitive exclusions
The responses of the innate system are activated by a protein receptors in the plasma membrane of defensive cells , among these activators are
Toll-like receptors (TLRs)
The TLRs attach to a various components commonly found on the pathogens that are called
pathogen associated molecular patterns (PAMPs)
defensive cells released by TLRs. Are proteins that regulate the intensity of and duration of the immune response
Cytokines
Roles of Cytokines
recruit other macrophages and dendritic cells to isolate and destroy microbes
activate T cells and B cells involved in adaptive immunity
own their name to the presence of large granules in their cytoplasm that can be seen under a light microscope
granulocytes
Three types of granulocytes:
neutrophils
basophils
eosinophils
contains two to five lobes, HIGHLY PHAGOCYTIC, and motile are active in the initial stage of infection. destroy microbes and foreign particles
neutrophils
releases substances such as HISTAMINE, important in inflammation and allergic response
basophils
produce toxic proteins against certain parasites
eosinophils
also have granules in their cytoplasm but the granules are not present in light microscope after staining
agranulocyte
Three types of agranulocytes
monocytes
dendritic cells
lymphocytes
not actively phagocytic until they leave circulating blood, enter tissues and mature into macrophages
monocytes
destroy microbes by phagocytosis and to initiate adaptive immune system.
dendriic cells
include natural killer cells and B and T cells
lymphocytes
PROCESS OF PHAGOCYTOSIS:
- chemotaxis and adherence
- ingestion of microbe by phagocyte
- formation of phagosome, (phagocytic vesicle)
4 fusion of phagosome with a lysosome to form a phagolysosome - Digestion of ingested microbes by enzymes in the phagolysosome
- formation of the residual body containing indigestible material
- discharge of waste materials
Four cardinal signs of inflammation
redness, pain, swelling, heat, and (loss of function)
White blood cells are divided into three categories
granulocytes
monocytes
lymphocytes
Inflammatory process
- damage tissue releases pro-inflammatory cytokines, which increases the blood vessels to dilate and become more permeable. Cardinal signs become present
- Endothelial cells lining the blood vessels produce adhesion molecules that catch the phagocytes as they pass
- phagocytes and fluid leak out of blood vessels movement DIAPEDESIS. neutrophils are the first phagocytes to arrive. secrete more cytokines to recruit more phagocytes.
- the phagocytes take up and destroy foreign microbes and damaged cells.
- Tissue repair
series of nine proteins circulating in blood and fluids. INACTIVE FORM.
Complement system
Three pathways of activation of the complement system:
alternative pathway
lecitin pathway
classical pathway
Activation of complement leads to major protective outcomes
inflammation
opsonization
lysis of foreign cells
