introduction to pathology dr:gehan mohamed
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Introduction to Pathology DR:Gehan mohamed. Definition of pathology. It is the “ Scientific study of disease" . "scientific study of the molecular, cellular, tissue, or organ system response to injurious agents.". - PowerPoint PPT PresentationTRANSCRIPT
It is the It is the ““Scientific study of disease" . "scientific study of the molecular,
cellular, tissue, or organ system
response to injurious agents."
Definition of pathology
Pathology serves as a Pathology serves as a ""bridgebridge"" or or ""linklink" " between between
the preclinical sthe preclinical sciencesciences ( (anatomy, physiology, anatomy, physiology, …………
etcetc.) and the courses in clinical medicine..) and the courses in clinical medicine.
Seven Seven Branches of PathologyBranches of Pathology
General PathologyGeneral PathologySystemic PathologySystemic PathologySurgical PathologySurgical PathologyGross PathologyGross PathologyCellular PathologyCellular PathologyClinical Pathology Clinical Pathology ImmunopathologyImmunopathology
General PathologyGeneral Pathology
Common changes in all tissues. e.g.. Inflammation, Common changes in all tissues. e.g.. Inflammation,
cancer, ageing, edema, hemorrhage ….etc.cancer, ageing, edema, hemorrhage ….etc.
Systemic Pathology Systemic Pathology
Discussing the pathologic mechanisms in relation to Discussing the pathologic mechanisms in relation to
various organ systems e.g. CVS, CNS, GIT…..etc.various organ systems e.g. CVS, CNS, GIT…..etc.
Techniques of Pathology
1. Human pathology
(1) Autopsy
(2) Biopsy
(3) Cytology: smear, fine needle aspiration
2. Experimental pathology
(1) Animal experiment: animal model
(2) Tissue and cell culture
Necropsy: Gross examination of the animal cadaver by systematic dissection in order to evaluate any abnormal changes (lesions) that may be present.
Autopsy: Synonymous to necropsy in human medicine
Biopsy: Removal and examination of tissue obtained from the living body
What is the Disease?
It is the It is the ““State in which an individual
exhibits an anatomical, physiological,
or biochemical deviation from the
normal”•Disease may be defined as :Disease may be defined as :
an abnormal alteration of structure or function in any part of
the body.
Classification of Diseases:
(A)Developmental(A)Developmental – genetic, congenital. – genetic, congenital.
(B)Acquired:(B)Acquired:
(1)Inflammatory(1)Inflammatory – Trauma, infections, immune, etc. – Trauma, infections, immune, etc.
(2)Neoplastic(2)Neoplastic – tumors cancers – tumors cancers
(3)Degenerative(3)Degenerative – ageing. – ageing.
(4)Metabolic(4)Metabolic..
(5)Iatrogenic: Drug induced(5)Iatrogenic: Drug induced..
• Definition.• Epidemiology – Where & When.• Etiology – What is the cause?• Pathogenesis - Evolution of dis.• Morphology - Structural Changes• Functional consequences• Management • Prognosis• Prevention
Pathology
What should we Know About A Disease
Knowledge of Knowledge of etiologyetiology remains the remains the
backbone of:backbone of:
Disease Disease diagnosisdiagnosis
Understanding Understanding the nature of diseasesthe nature of diseases
Treatment Treatment of diseases.of diseases.
Etiology Etiology “Study of the cause of a disease"“Study of the cause of a disease"
Etiology Etiology “Study of the cause of a disease"“Study of the cause of a disease"
An etiologic agentAn etiologic agent : :
is the factor (bacterium, virus, etc.) responsible for lesions or a is the factor (bacterium, virus, etc.) responsible for lesions or a
disease state.disease state.
Predisposing Causes of Disease:Predisposing Causes of Disease:
Factors which make an individual more susceptible to a Factors which make an individual more susceptible to a
disease (damp weather, poor ventilation, etc.)disease (damp weather, poor ventilation, etc.)
Exciting Causes of Disease:Exciting Causes of Disease:
Factors which are directly responsible for a disease (hypoxia, Factors which are directly responsible for a disease (hypoxia,
chemical agentschemical agents , virus, bacteria …. , virus, bacteria …. etc.). etc.).
•One One etiologic agent etiologic agent several several diseases, as diseases, as smoking.smoking.
Disease
• Several etiologic Several etiologic agents one agents one disease, as cancer .disease, as cancer .
Disease Disease
DiseaseDisease
One etiologic One etiologic agent agent - - one disease, as one disease, as Malaria.Malaria.
EtiologyEtiology
PathogenesisPathogenesis
The sequence of events in the response of the cells or tissues to the etiologic agent, from the initial stimulus to the ultimate expression of the disease.
CELLS Response to injurious CELLS Response to injurious agentagent
Either :Either :ADAPTINGADAPTINGSUSTAINING REVERSIBLE INJURYSUSTAINING REVERSIBLE INJURYSUFFERING IRREVERSIBLE SUFFERING IRREVERSIBLE INJURY AND DYINGINJURY AND DYING
Clinical Symptoms & SignsClinical Symptoms & Signs
Clinical signs are seen only in the living Clinical signs are seen only in the living
individualindividual as organomegaly as organomegaly..
Clinical sClinical symptoms ymptoms are are the patient’s the patient’s
complain usually by its own words as pain.complain usually by its own words as pain.
Morphologic changeMorphologic change Characteristic of the diseaseCharacteristic of the disease
Diagnostic of the etiologic Diagnostic of the etiologic processprocess
Functional Functional derangementsderangements
MORPHOLOGYMORPHOLOGY
Morphology remains at the Morphology remains at the heart of diagnostic heart of diagnostic pathology.pathology.
(2)Microscopic examination for tissue sections fixed in formalin then stained by
HE (hematoxylin and eosin) to be examined by light microscope for Histologic and cytologic changes.
Hemangioma
(4)Flow cytometry (FCM)
In neoplastic diseases Can determine :
1- If there is One kind of cells→quantitative assesment
2. DNA ploidy analysis (amount of DNA)
( 5 ) Image analysis (IA) it can determine Nuclear diameter;
circumference; area; volume;
morphology