cell membrane damage early on; destruction of organelles and leakage of cytoplasm; causes inflammation
necrosis
programmed cell death; does not cause inflammation; cell shrinks and cellular fragments are packaged into pieces of cell membrane and dispersed
apoptosis
area adjacent to the ischemic core where cells undergo apoptosis
ischemic penumbra
evolutionary ancient immune response; immediate activation with inflammation
innate immunity
immune response that targets specific structure via antibodies and cytotoxic T cells; slow
adaptive immunity
cause direct injury at site of infection or release toxins that can cause systemic illness
bacteria
nucleic acids surrounded by protein coat that invade cells to produce copies of themselves
viruses
need to live off a host to complete life cycles
parasites
What are some physical barriers to infection?
- skin
- respiratory tract
- GI tract
- genitourinal system
How does the skin protect from infection?
- keratinized epithelium
- normal cutaneous microbial flora (inhibit colonization of other bacteria)
- normal sebaceous and sweat glands (secretions are acidic, antimicrobial, contain anti-fungal fatty acids, lactic acid, lysosome, and antibodies)
How does the respiratory tract protect from infection?
- cough and sneeze reflexes
- mucociliary escalator
- antibodies
- collectins
- alveolar macrophages
How does the GI tract protect from infection?
- epithelial barrier
- the microbiome
- low gastric pH
- peristaltic movement
- antibodies
If pathogens do make it through the GI tract, whats another method of protection?
they enter the blood which is rerouted to the liver – destroyed by Kuppfer cells (liver macrophages)
How does the genitourinal tract protect from infection?
- physical flushing of urine
- low vaginal pH
- normal vaginal flora
What are the characteristics of inflammation?
- rugor (redness)
- calor (warmth)
- dolor (pain)
- tumor (swelling)
What do neutrophils do?
- first on scene
- release mediators to promote inflammation and vasodilation
- chemotaxis
What are macrophages and what do they do?
- derived from monocytes (enter tissue and change into macrophages)
- phagocytize and destroy foreign cells/particles
What are dentritic cells and what do they do?
- similar to macrophages but not derived from monocytes
- in CNS –> microglia
- clean up debris and maintain other cells
Where is histamine released from and what does it do?
- released from mast cells in tissues
- vasodilation and increased vascular permeability
Where are eicosinoids released from and what do they do?
- produced by virtually all cells
- includes prsotaglandins and leukotrienes (aspirin inhibits these)
Where is neuropeptide released from and what does it do?
- released from sensory C-fiber neurons
- increases sensitivity of noniceptors (increased pain sensation)
Where are cytokines released from and what do they do?
- released from immune cells
- examples: IL-1, IL-6, TNF, interferons
- regulate immune response (activate and inhibit)
- can act locally or systemically
cytokine that is a non-specific blocker of viral replication
interferon
Where are plasma proteins released from and what do they do?
- produced in liver in response to cytokines
- complement – antibody production
- clotting proteins
- C-reactive protein – facilitates phagocytosis
