Download Clinical pathology

Introduction of Pathology
Dr Prom Phanit, DTM & H, MCTM
Objectives
• Define common terms used in Pathology
• Appreciate the deviations from normal to
abnormal structure and functions of the body
system.
Definition of pathology
• Pathology is the scientific study of disease. It
includes the functional and structural
changes in disease.
• It is often studied in specimen obtained postmortem, or following death.
• The abnormal specimens may be grossly visible
with the naked eye, or may only be observed
microscopically.
History of Pathology (1)
• Morbid anatomy: The first opportunity for the
scientific study of disease come from the
thorough internal examination of the body after
death- autopsies have been performed
scientifically from about 300 BC and have
revealed much information of many diseases.
• The term "autopsy" derives from the Ancient
Greek autopsia, "to see for oneself",
History of Pathology (1)
• Around 3000 e ancient Egyptians were one of
the first civilizations to practice the removal and
examination of the internal organs of humans
in the religious practice of mummification
History of Pathology (1)
History of Pathology (1)
History of Pathology (2)
• Microscopic and cellular pathology:
Pathology was revolutionized by the application
of microscopy (1800). 200 years ago nothing
was known of bacteria, viruses, ionizing
radiation, carcinogenic chemicals.
• Rudolf Virchow (1821-1902) , a German
pathologist recognized cells by microscope as
cellular pathology.
History of Pathology (3)
• Molecular Pathology: is the techniques
with relatively simple principle can reveal
of the change of the single nucleotide of
genomic DNA resulting in the synthesis of
defective gene product for particular
disease.
History of Pathology (4)
• Cellular and Molecular alteration in disease :
We now have a clearer understanding of the way
in which diseases can be attributed to
disturbances of normal cellular and molecular
mechanism.
• For example: Cellular –nucleus (genes encoded
in DNA) – inherited or spontanous mutations
(inherited, metabolic disorders, cancer).
Goal and objective of pathology
• Why we study pathology?
• The ultimate goal of pathology is the
identification of the causes of disease,
• To help in diagnosis in some specific diseases
such as cancers.
• To be successful in therapy and to disease
prevention.
Scope of Pathology (1)
• Clinical and experimental pathology:
• Scientific knowledge about human diseases is
divided from observation, or from experimental
studies of animals and cell cultures.
• The greatest contribution comes from the
detailed study of tissues and body fluids from
patients.
Scope of Pathology (2)
• Clinical pathology: clinical pathology is concerned
with a cross sectional analysis at the level of the disease
itself, studies the cause and mechanisms of the disease,
and the effects of the disease upon the various organs
and systems of the body.
• Experimental pathology: Experimental pathology is
the observation of the effects of manipulations on
experimental systems such as animal models of disease
or cell culture.
Scope of Pathology (3)
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Subdivisions of clinical pathology:
Histopathology: examination of tissues
Cytopathology: examination of isolate cells
Haematology: the study of disorders of
cellular and coagulable components of blood
• Microbiology : the study of infectious disease
and the organisms
Scope of Pathology (4)
• Immunology: the study of specific defense
mechanisms of the body
• Chemical pathology: the study and diagnosis of
disease from the chemical change in tissue and fluids
• Genetic: the study of abnormal chromosomes and
genes
• Toxicology: the study of the effects of know or
suspect of poisons
• Forensic pathology: the application of pathology to
legal purposes ( e.g investigation of death)
Techniques of Pathology (1)
• Gross pathology- Before microscopy was
applied to medical problems (year 1800),
observations were confirmed by unaided eye
• Light microscopy- advances in optics and the
quality of lenses have resulted in a wealth of
new information about the structure of tissues
and cells in health and disease from microscopy
Techniques of Pathology (2)
• Histochemistry- is the study of the chemistry of
tissues, usually by microscopy of tissue section after
they have been treated with specific reagents.
• Immunohistochemistry and immunofluorescenceemploy antibodies (immonoglobulins with antigen
specificity) to visualise substances in tissues section or
cell preparation. These techniques use antibodies linked
chemically to emzymes or fluorescent dyes respectively.
Techniques of Pathology (3)
• Electron microscopy- has extended the range of
pathology to the study of disorders at the organelle
level, and to the demonstration of viruses in tissue
samples from same diseases.
• Biochemical Techniques- applied the body’s tissues
and fluids in health and diseases. The clinical role of
biochemitry is examplified by the importance of
monitoring fluid and electrolyte omeostesis in many
disorders. Example serum enzymes assay.
Techniques of Pathology (4)
• Haematological Techniques- are used in
diagnosis and study of blood disorders.
• Cell cultures – are widely used in research and
diagnosis. Cell cultures are used to prepare
chromosome spread for cytogenetic analysis.
Techniques of Pathology (5)
• Medical Microbiology- is the study of disease caused
by microorgnism such as bacteria, fungi, viruses and
parasites.
• Molecular pathology – reveal defects in the chemical
structure of molecule arising fromerrors in the genome,
the sequence of bases that direct amino acid synthesis.
Example DNA microarray can be used to determine
patterns of gene expression (mRNA).
Questions
• Define pathology, post mortem (autopsy),
specimen?
• What is microscopic and cellular pathology?
What is clinical pathology?
• What is molecular pathology?
• What is experimental pathology?
• What is forensic pathology?
• Why we study pathology?