Pathology is the scientific study of disease, encompassing etiology (the cause), pathogenesis (mechanism), morphologic changes (structural alterations), and functional derangements. It involves various techniques such as histopathology, cytopathology, and biochemical examination to diagnose and understand diseases. Biopsies and cytological examinations are key methods for identifying diseases, including cancer, through the analysis of tissue and cell samples.

1. By – Annu Maurya

2.  Pathology is the study of disease by scientific
methods. The word pathology came from the
Latin words “patho” & “logy”. ‘Patho’ means
disease and ‘logy’ means study, therefore
pathology is a scientific study of disease.
Diseases may, in turn, be defined as an
abnormal variation in structure or function of
any part of the body.

3.  1. Etiology,
 2. Pathogenesis,
 3. Morphologic changes and
 4. Functional derangements and clinical
significance.

4.  Etiology of a disease means the cause of the
disease. If the cause of a disease is known it
is called primary etiology. If the cause of the
disease is unknown it is called idiopathic.

5.  genetic
 acquired

6.  Pathogenesis means the mechanism through
which the cause operates to produce the
pathological and clinical manifestations. The
pathogenetic mechanisms could take place in
the latent or incubation period. Pathogenesis
leads to morphologic changes.

7.  The morphologic changes refer to the
structural alterations in cells or tissues that
occur following the pathogenetic
mechanisms. The structural changes in the
organ can be seen with the naked eye or
they may only be seen under the microscope.
Those changes that can be seen with the
naked eye are called gross morphologic
changes & those that are seen under the
microscope are called microscopic changes.
Both the gross & the microscopic
morphologic changes may only be seen in
that disease

8.  The morphologic changes in the organ
influence the normal function of the organ
 Etiology - Pathogenesis -Morphologic changes
-Clinical features & Prognosis of all diseases.

9.  a. Histopathology
 b. Cytopathology
 c. Hematopathology
 d. Immunohistochemistry
 e. Microbiological examination
 f. Biochemical examination
 g. Cytogenetics
 h. Molecular techniques
 i. Autopsy

10.  Histopathological examination studies tissues
under the microscope. During this study, the
pathologist looks for abnormal structures in
the tissue. Tissues for histopathological
examination are obtained by biopsy. Biopsy is
a tissue sample from a living person to
identify the disease. Biopsy can be either
incisional or excisional.

11.  Cytopathology is the study of cells from various
body sites to determine the cause or nature of
disease. Applications of cytopathology:
 The main applications of cytology include the
following:
 1. Screening for the early detection of
asymptomatic cancer For example, the
examination of scrapings from cervix for early
detection and prevention of cervical cancer.
 2. Diagnosis of symptomatic cancer
Cytopathology may be used alone or in
conjunction with other modalities to diagnose
tumors revealed by physical or radiological
examination

12.  3. Surveillance of patients treated for cancer For
some types of cancers, cytology is the most feasible
method of surveillance to detect recurrence. The
best example is periodic urine cytology to monitor
the recurrence of cancer of the urinary tract.

13.  This is a method by which abnormalities of
the cells of the blood and their precursors in
the bone marrow are investigated to
diagnose the different kinds of anemia &
leukemia.

14.  This is a method is used to detect a specific
antigen in the tissue in order to identify the
type of disease.

15.  This is a method by which body fluids,
excised tissue, etc. are examined by
microscopical, cultural and serological
techniques to identify micro-organisms
responsible for many diseases.

16.  This is a method by which the metabolic
disturbances of disease are investigated by
assay of various normal and abnormal
compounds in the blood, urine, etc.

17.  This is a method in which inherited
chromosomal abnormalities in the germ cells
or acquired chromosomal abnormalities in
somatic cells are investigated using the
techniques of molecular biology.

18.  Different molecular techniques such as
fluorescent in situ hybridization, Southern
blot, etc... can be used to detect genetic
diseases.

19.  Autopsy is examination of the dead body to
identify the cause of death. This can be for
forensic or clinical purposes.