2026
what is the first line of defense - Answers - innate, natural, native
- physical, mechanical, biochemical barriers
ex: skin, eyelashes, cilia
what is the second line of defense - Answers - innate
- inflammation
what is the third line of defense - Answers adaptive, acquired, specific immunity
viruses vs bacteria - Answers viruses: no cell wall, bundles of RNA, hijacks host cells to replicate
inside, cell ruptures
bacteria: cell walls, complex, use host's nutrients/resources to multiply, replicates outside our
cells
consequences of an excessive/ineffective inflammatory response - Answers - local tissue
damage from compression
- development of chronic inflammation
- systemic pathology: atherosclerosis, chronic renal disease, neurological disorders
steps in acute inflammatory response - Answers 1. tissue injury and release of chemical
mediators
2. vasodilation and increased blood flow
3. swelling and retraction of activated endothelial cells
4. increased vascular permeability and leakage of small plasma proteins
5. "walling off" - keeps fluid & cells in site of injury
6. movement of immune response cells to site of injury
7. exudate formation - dead tissue cells (neutrophils), lymphatic fluid, yellow part of blood
8. movement of glucose and oxygen to site needing repair
9. release of chemical repair factors from activated endothelial cells
stages of acute inflammation - Answers 1. vascular stage/response
, 2. cellular stage/response
what is the vascular stage/response - Answers - facilitated by chemical mediators
- blood vessels dilate (increased blood flow to site)
- increased vascular permeability (allows fluid & cells to move from vessels to site)
what is the cellular stage/response - Answers - regulated by inflammatory mediators
- 3 steps:
1. chemotaxis - inflammatory cells signalled to come help
2. cellular adherence - leukocytes adhere to endothelial lining
3. cellular migration (diapedesis) and phagocytosis - leukocytes migrate towards site of injury
through openings between cells, monocytes become macrophages and engulf bacteria & dead
cells
what are inflammatory/chemical mediators - Answers - initiate inflammatory response
ex: kinins, prostaglandins, histamine
blood clot vs clot - Answers blood clot: platelets gather at injury, fibrin strands join and form a
mesh that captures other cells to seal off and get rid of debris
clot: plugs damaged vessels, traps microbes to contain them, is the framework for future
healing
endothelial cells - Answers - shrink to increase permeability
- allow adhesion and migration of leukocytes to site of injury
- control clotting mechanisms (to allow fibrin and continued blood flow)
- regulate immune cell proliferation through secretion of CSFs (colony-stimulating factors)
leukocytes (WBCs) - Answers ex: neutrophils, eosinophils, mast cells, basophils
- contain active inflammatory mediators histamine, leukotriene, and prostaglandins
mast cells - Answers - a WBC
- from marrow
- matures in tissue
- has lots of granules