medsci 203 #1 Flashcards
Pathology
Medical science and practice concerned with all aspects of disease.
Pathology is an important discipline or acts as a critical bridge between basic science and clinical medicine.
Morbid anatomy
Post-mortem macroscopic examination of disease. Benn practised since Classical Greek times.
1600s - Vesalius.
Observational science.
Cellular and histopathology
- Developed from the discoveries of Louis Pasteur (studied the effects of microorganism) and Rudolf Virchow (recognised that the cell is the basic living unit of disease).
Molecular pathology
Describes disease processes in terms of biochemical and molecular biological processes.
Anatomical pathology
Macroscopic and microscopic study of tissue. Observational science.
General pathology
Mechanisms of disease. Investigation of processes underlying disease conditions. Experimental science.
The pathogenesis of a disease is the mechanisms of its development.
Aetiology
Causes
Cyto-
relating to cells. E.g. cytotoxicity
Dys-
Disordered. E.g. Dysplasia.
Hyper-
An excess over normal. e.g. Hyperplasia
Hypo-
A deficiency below normal. E.g. Hypothyroidism.
Leuko-
White E.g. leukocyte.
Meta-
A change of one state to another. E.g. Metaplasia.
Neo-
New. E.g. neoplasia.
-aemia
relating to the blood. E..g Anaemia.
-cytosis
An increased number of cells. E.g. Leukocytosis.
-itis
An inflammatory process. E.g. Appendicitis
-oid
having a resemblance to something. E.g. Epithelioid.
-oma
a growth. E..g atheroma, lymphoma.
-opathy
a diseased state. E.g. aden-patchy.
-osis
a state or condition. E.g. acidosis.
-penia
a lack of something. E.g. lymphopenia.
-plasia
a disorder of growth. E.g. anaplasia, metaplasia.
Crohn’s disease (CD)
First appears in adolescence or young adults. Occurs mainly at the end of the SI (Ileum) but can occur anywhere in the gut.
Affected areas of CD
are inflamed, red, swelling, pain, leukocyte infiltration.
- Epithelial lining ulcerates
Colon wall in CD.
may undergo excessive damage or fibrotic thinking.
Lumen narrows with obstruction (stenosed)
- Cracks/fissures develop through the bowel wall and drain into pus-filled cavities (abscesses) or form channels (fistulas) into nearby loops of bowel.
Immune system during CD
Immune system is activated with aggregations of lymphocyte (follicles) and macrophages (granulomas). and enlarged lymph nodes.
Probability of developing cancer (neoplastic disease) is increased.
Multiple etiological factors have been implicated in CD
- Family history suggest a genetic contribution. 30% Caucasians with CD have NOD2 gene mutated.
- Environmental factors. Incidence increase last 40 years. Diet, NSAIDs, tobacco, increased hygiene.
- Microbial factors. E.g. pathogenic infections as triggers.
- Uncontrolled immune response to commensal bacteria damage the bowel. E..g overactive TH1 cells which secrete TNF or under-active Treg cells.
NOD2 protein
Pattern recognition receptor for bacterial products. May be needed for autophagic elimination of intracellular bacteria and for the antimicrobial activity of Paneth cells.
Suggested outline of the pathogenesis of CD
- Environmental trigger may damage the mucosa.
- Damage (with bacterial invasions of submucosa) induces an inflammatory repose and healing.
- People with a genetic deficiency in innate immunity or barrier function may be unable to repair the damage or eliminate the microbes from the submucosa (+ lifestyle/environmental).
- Uncontrolled T cell responses may develop against commensal bacteria and ultimately damage the colon wall.