Inflammation Flashcards
Inflammation definition
A reaction to injury or infection involving cells such as neutrophils and macrophages
Autoimmunity definition
When the body produces an inflammatory reaction to its own healthy cells and tissues.
Granulation tissue definition
New connective tissue and microscopic blood vessels that form on the surfaces of wound during the healing process
Granuloma definition
A type of chronic inflammation where a mass of granulation tissue is formed in response to infection, inflammation or the presence of a foreign substance. They are lots of pale macrophages surrounded by lymphocytes
Mycetoma definition
Chronic inflammation of the tissues caused by a fungus or certain bacteria
Tuberculoma definition
A manifestation of tuberculosis where tubercles form a firm lump
What is acute inflammation?
Sudden onset and short duration inflammation. It usually resolves relatively quickly. Involves neutrophils
What is chronic inflammation?
Inflammation which is slow onset or following acute inflammation. It has a long duration and may never resolve. It involves lymphocytes and macrophages
What are neutrophil polymorphs and what do they do?
- They are short lived and the most common WBCs
- They attack the pathogen first and are directly at the site of inflammation producing pus
- They have cytoplasmic granules full of enzymes to kill bacteria
They release chemicals that attract other inflammatory cells
What are macrophages and what do they do?
- Longer lived WBCs (weeks-months)
- Have phagocytic properties
- Ingest bacteria and carry debris to lymph nodes
- Present antigens to lymphocytes
- 2nd wave of attack
What are lymphocytes and what do they do?
- Longer lived WBCs (years – lifetime)
- Produce chemicals which attract other inflammatory cells
- Have immunological memory for past infections and antigens
What are endothelial cells and what do they do?
- Line capillary blood vessels
- Become sticky in inflammation so inflammatory cells adhere to them
- Become porous to allow inflammatory cells to pass into tissues
- Grow into areas of damage to form new capillaries
What are fibroblasts and what do they do?
- Long lived cells which synthesise extracellular matrix and collagen
- Form collagen in areas of chronic inflammation and repair which causes scarring
What are the macroscopic appearances of acute inflammation and why?
- Redness (rubor) - dilatation of small blood vessels in the damages area
- Heat (calor) - increased blood flow causes increased vasodilation; some inflammatory chemical mediators also increase temperature
- Swelling (tumor) - oedema, large mass of inflammatory cells, new connective tissue formation
- Pain (dolor) - stretching of tissues from swelling; some chemical mediators also induce pain e.g bradykinin, prostaglandins, and serotonin
- Loss of function – movement consciously and reflexively inhibited; severe swelling may also inhibit movement
Describe the acute inflammatory response process
- Arterioles dilate = more blood to flow through capillaries
- Capillary pressure increases = more protein leaves the blood vessels = increased osmotic pressure
- More fluid is forced out of the blood vessels and doesn’t re-enter = oedema
Name the 6 chemical mediators of acute inflammation (endogenous chemical mediators)
- Histamine
- Thrombin
- Lysosomal compounds
- Prostaglandins
- Serotonin
- Chemokines
Give 5 effects of the endogenous chemical mediators
- Vasodilation
- Emigration of neutrophils
- Chemotaxis
- Increased vascular permeability
- Itching and pain
What is the source and function of histamine and what stimulates it to be released?
- Mast cells (mostly), also in basophils, eosinophils and platelets.
- Causes vascular dilation and the immediate transient phase of increased vascular permeability
- Stimulated by C3a and C5a (complement components) and lysosomal proteins released from neutrophils
Give 6 causes of acute inflammation
- Microbial infections
- Hypersensitivity reactions
- Physical agents e.g trauma, ionising radiation
- Chemicals
- Bacterial toxins
- Tissue necrosis
Give 4 causes of chronic inflammation
- Primary - No initial acute inflammation
- Transplant rejection
- Progression from acute inflammation - occur is pus forms in a deep seated abscess so it cannot drain and the cavity walls become rigid and must be healed by granulation tissue ingrowth
- Recurrent episodes of acute inflammation
Give 5 macroscopic appearances of chronic inflammation
- Chronic ulcer
- Chronic abscess cavity
- Thickening of the wall of a hollow organ
- Granulomatous inflammation
- Fibrosis
Describe some microscopic features of chronic inflammation
- Lymphocytes, plasma cells & macrophages present
- A few eosinophil polymorphs may be present but neutrophil polymorphs are scarce
- Some of the macrophages may form multinucleate giant cells
- Production of new fibrous tissue from granulation tissue
- Evidence of continuing destruction of tissue as well as tissue regeneration and repair
- Tissue necrosis
How do you treat inflammation?
- Remove the cause of inflammation
- NSAIDS
- Corticosteroids
