week 2 - 1- introduction of pathology.ppt

8/10/2019 WEEK 2 - 1- introduction of pathology.ppt

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Pathology is the study (logos) of

suffering (pathos). 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

functionalchanges 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 of

disease process (e.g. inflammation,tumours, degenerations).

sys temat ic patho logy: the descriptions

of specific diseases as they affectindividual organsor organ systems (e.g.

appendicitis, lung cancer, atheroma).


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Pathological examination

Clinical

Examination

External

examinationBody

Macroscopically (Naked

eye)

Grosspathology

Anatomicalpath.Organ

Microscopically

( Light- microscopy)HistopathologyTissue

Ultra-structure (Electron-

microscopy)Cell pathologyCell

Gene analysisMolecular

pathologyGene


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HEALTH

As generally used, the term "health"

refers to the "state in which an

individual is living in complete

harmony with his environment,"


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Dis + ease (not atease)

WHO def. as a "state

in which an

individual exhibits

physiological,

anatomical,

histological deviation

from the normal."

DISEASE


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Disease Types

Inflammatory / Neoplastic / Degenerative

Acute / Chronic

Acuteshort days to weeks.

Chroniclongmonths to years.

Congenital / Familial / Acquired

Mild / Moderate / Severe


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TIOLO Y

The term "etiology"refers to a "study of the cause

of a disease."An etiologic agent responsible for a

disease state.

Predisposing Causes of Diseases: refer to those

factorswhich make an individual more susceptible

to a disease (damp weather, poor ventilation, etc.)

Exciting Causes of Disease: refer to those factors

which 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:Diabetes,HypertensionCancer


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One agent Onedisease - Malaria

Severalagents Onedisease -Diabetes

One agent Several diseases - Smoking

Disease

Disease

Disease

DiseaseDisease


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P THOGENESIS

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 ordeath."


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CLINICAL SIGNS

"Clinical signs" refer to any

"functional and structural

evidence of disease which

can be determined by the

physician"


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Lesion The term lesion is generally used to refer to

"structural or morphological alterationsassociated with a diseased 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

is specifically characteristic of a disease. Whenone sees a pathognomonic lesion, he knows that

a particular disease is present.


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I GNOSIS

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 of

clinical 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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PRO NOS S

The term Prognosis" refers to the

probably outcome of a disease in a

living individual. It is the clinician's

estimate of the severity and possible

result of a disease.


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Subdivisions of Pathology

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

Histopatholog y: the investigation and diagnosis of

disease from the examination of tissues.

Cytopathology: the investigation and diagnosis ofdisease from the examination of isolated cells.

Haematolog y: the study of disorders of the cellular

and coagulable components of blood.

Microb io logy: the study of infectious diseases andthe organisms responsible for them.

Immunology: the study of the specific defense

mechanisms of the body


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Chemical pathology: the study and

diagnosis of disease from the chemical

changes in tissues and fluids

Genetics: the study of abnormal

chromosomes and genes

Tox icology: the study of the effects of

known or suspected poisons

Forensic patho logy: the application of

pathology to legal purposes (e.g.

investigation of death in suspiciouscircumstances).


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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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week 2 - 1- introduction of pathology.ppt

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