pathology

1. Introduction to pathology
by
Shatha Abdelmawla Al Sulh
M.Sc., M.B.B.Ch

2. Pathology
• Deffinition: it is the science of diseases.
(abnormalities in structure & function).
• It is the study of abnormal anatomy, abnormal histology, abnormal biochemistry
and abnormal physiology.
• It is the basis for all branches of clinical sciences.
• Divided to :
 General pathology.
 Special pathology oral pathology.

3. The main aspects of any disease:
• Diffinition and categorization.
• Aetiology:
 Predisposing factors.
 Exciting cause or causative organism.
 Pathogenesis (michanism).
• Clinical picture :
Morphologic changes in the lesion (locally):
 Gross : by naked eye.
 Microscopic : by light microscope.
 Special microscopic studies : EM & immunohistochemistry.
General body reaction to tissue damage (systymic manifestations)

4. The main aspects of any disease
(cont.):
• Fate : course of the disease.
Good : regressive.
Bad: comlicated or even leading to death.
• Prognosis : prediction of the course.
Good: as benign tumor.
Poor: as malignant tumor.

5. Causes of cell injury:
• Infectious agent.
• Hypoxia :ischemia, inadequet oxygenation & decreased oxygen carrying capacity.
• Physical agent.
• Chemical agent.
• Immunologic reaction.
• Nutritional deficiencies.
• Genetic disorders.

6. Results of cellular and tissue injury:
Cell injury:
Reversible (degeneration).
Irreversible (necrosis-apoptosis).
Inflammation.
Repair (healing of tissue injury).

7. Results of cellular and tissue injury: (cont.)
Accumulations (cause or result):
Intracellular.
Extracellular.
Cellular adaptation (atrophy,hypertrophy,hyperplasia, metaplasia).
Abnormal cell growth (dysplasia,neoplasia).
Vascular disturbances e.g edema,thrombosis and shock.

8. How to diagnose a disease?
Clinical picture:
 History taking =symptoms of the patient
 Clinical examination =signs of the disease discovered
on examination (local & systemic).
Differential diagnosis
• based on signs & symptoms.

9. How to diagnose a disease? (cont.)
• Special investigations:
• laboratory investigations
• imaging
• pathological examination of specimens.

11. Inflammation

12. • Deffinition: reaction of living vascularised tissues to injury.
• Characterised by:
• local vascular & cellular phases (lead to formation of fluid & cellular
exudate)
• systemic manifestations.
• It is protective: removal of the cause or products of injury.
• May have adverse effects (complications).

13. Aetiology: injurious agents.
• Infection.
• Physical.
• Mechanical.
• Chemical.
• Antigens hypersinsitivity reaction.

14. Types of inflammation:
•Acute : rapid onset, short duration.
•Subacute: grade inbetween.
•Chronic: gradual onset, long duration.