1- Introduction of Pathology

8/8/2019 1- Introduction of Pathology

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The term pathology is defined as

the "scientific study of the

molecular, cellular, tissue, ororgan system response to

injurious agents.

The study of the structural and

functional changes in cells,

tissues, and organs that underlie

disease.


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LEARNING PATHOLOGY

Pathology is best learnt in two stages:

general pathology: the mechanisms and

characteristics of the principal types ofdisease process (e.g. inflammation,

tumours, degenerations)

systematic pathology: the descriptions of

specific diseases as they affect individual

organs or organ systems (e.g.

appendicitis, lung cancer, atheroma).


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Pathologicalexamination

Clinical

Examination

External

examinationBody

Macroscopically(Nakedeye)

GrosspathologyAnatomicalpath.

Organ

Microscopically

( Light- microscopy)HistopathologyTissue

Ultra-structure(Electron- microscopy)

CellpathologyCell

GeneanalysisMolecular

pathologyGene


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HEALTH

As generally used, the term "health"

refers to the "state in which anindividual is living in complete

harmony with his environment,"


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Dis + ease (notat ease)

WHO def. as a"state in whichan individualexhibits

physiological,anatomical,histologicaldeviation fromthe normal."

DISEASE


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DiseaseTypes

Inflammatory / Neoplastic /Degenerative

Acute / Chronic

Acute short days to weeks.

Chronic long months to years.

Congenital / Familial / Acquired Mild / Moderate / Severe


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ETIOLOGY

The term "etiology" refers to a "study of thecause of a disease." An etiologic agentresponsible for a disease state.

Predisposing Causes of Diseases: refer to thosefactors which make an individual more susceptibleto a disease (damp weather, poor ventilation,etc.)

Exciting Causes of Disease: refer to those factorswhich are directly responsible for a disease(bacteria, viruses, hypoxia, chemical agents,etc.).


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Etiology: What is the cause?

Environmental agents: Physical

Chemical

Nutritional Infections

Immunological

Psychological

Genetic Factors: Age

Genes

Multifactorial:Multifactorial:Diabetes,Diabetes,HypertensionHypertensionCancerCancer


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OneOne agentagent OOnene diseasedisease -- MalariaMalaria

SeveralSeveral agentsagents OOnene diseasedisease -- DiabetesDiabetes

OneOne agentagent SSeveraleveral diseasesdiseases -- SmokingSmoking

Disease

Disease

Disease

DiseaseDisease


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PATHOGENESIS

The term Pathogenesis" refers to

the "progressive development(sequence of events) of a disease

from the time it is initiated to its

final conclusion in recovery or

death."


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CLINICAL SIGNS

"Clinical signs" refer toany "functional and

structural evidence ofdisease which can be

determined by the

observer" (lameness,

salivation, increasedrespiratory efforts,

etc.).


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Lesion

The term lesion is generally used to refer to "structuralor morphological alterations associated with adiseased state in an individual."

Lesions may be recognized with the naked-eye (gross

lesions). with the aid of a light microscope (microscopic

lesions).

or with the aid of the electron microscope(ultrastructural lesions).

Pathognomonic Lesion: refers to a change which isspecifically characteristic of a disease. When one sees apathognomonic lesion, he knows that a particulardisease is present.


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DIAGNOSIS

The term Diagnosis" refers to the

"determination of the nature of a disease

expressed in a concise manner.

A clinical diagnosis is made on the basis ofclinical signs observed in the living individual.

A morphologic or anatomic diagnosis is based on

the location and nature of the lesion.

Etiologic diagnosis is made on the basis of the

cause.


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PROGNOSIS

The term Prognosis" refers to the

probably outcome of a disease in a livingindividual. It is the clinician's estimate of

the severity and possible result of a

disease.


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SubdivisionsofPathology

Pathology is a vast subject with many ramifications. In practice, however, ithas major subdivisions:

Histopathology: the investigation and diagnosis of disease from the

examination of tissues.

Cytopathology: the investigation and diagnosis of disease from the

examination of isolated cells.

Haematology: the study of disorders of the cellular and coagulable

components of blood.

Microbiology: the study of infectious diseases and the organisms

responsible for them.

Immunology: the study of the specific defense mechanisms of the body

Chemical pathology: the study and diagnosis of disease from the chemicalchanges in tissues and fluids

Genetics: the study of abnormal chromosomes and genes

Toxicology: the study of the effects of known or suspected poisons

Forensic pathology: the application of pathology to legal purposes (e.g.

investigation of death in suspicious circumstances).


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Pathology Summary

Scientific Study of Disease

Study of PathologyEtiology: What causes disease?.

Pathogenesis: How does disease develop?

Lesion: Structural change in disease?

Clinical Significance: Link to clinical F?


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Documents

1- Introduction of Pathology