Pathology is the study and diagnosis of disease through examination of organs, tissues, bodily fluids, and whole bodies. There are three main subtypes of pathology: anatomical pathology, which examines tissues and organs; clinical pathology, which diagnoses disease through laboratory analysis of fluids and tissues; and molecular pathology, which studies disease at the molecular level. Pathology is important for understanding disease causes and patterns, aiding diagnosis, and developing treatments through research. Pathologists manage laboratories and use various techniques to investigate diseases, conduct research, diagnose patients, and develop vaccines and cures.

1. Clinical Pathology

2. • Basic Pathology
• Unit 1: General Pathology
• 1. Introduction to Pathology
• 2. Fields of pathology
• 3. Importance of Pathology
• 4. Application of Pathology in Laboratory
diagnosis

3. Introduction to Pathology
• Pathology is the study and diagnosis of disease
through examination of organs, tissues, bodily
fluids, and whole bodies (autopsies).
• The history of pathology can be traced to the
earliest application of the scientific method to the
field of medicine, a development which occurred
in the Middle East during the Islamic Golden Age
and in Western Europe during the Italian
Renaissance.

4. • Early systematic human dissections were carried out
by the Ancient Greek physicians Herophilus of
Chalcedon and Erasistratus of Chios in the early part
of the third century BC.
• The first physician known to have made
postmortem dissections was the Arabian physician
Avenzoar (1091–1161).
• Rudolf Virchow (1821–1902) is generally
recognized to be the father of microscopic
pathology. Most early pathologists were also
practicing physicians or surgeons.

5. • A pathologist is a medical healthcare provider who
examines bodies and body tissues.
• He or she is also responsible for performing lab
tests.
• A pathologist helps other healthcare providers reach
diagnoses and is an important member of the
treatment team.

6. Fields of pathology
• There are three main subtypes of pathology:
anatomical pathology, clinical pathology, and
molecular pathology.
• These subtypes can be broken down into even
more specific categories; pathology is a diverse
field because so many different diseases and ways
of studying diseases exist.

7. Anatomical Pathology
• Anatomical pathology is the study of anatomical
features, such as tissue removed from the body, or
even an entire body in the case of an autopsy, to
diagnose and increase knowledge of disease.
• Anatomical pathology can include looking at cells
under a microscope, but it also involves looking at
organs in general (e.g. a ruptured spleen).
• It also includes investigation of the chemical
properties of cells, and their immunological
markers.
• There are several broad subcategories of
anatomical pathology:

8. Surgical pathology
• Surgical pathology is the examination of tissues
removed during surgery.
• A common example is the examination of a small
piece of tumor tissue to determine whether the
tumor is malignant (cancerous) or benign and
make a diagnosis.
• This procedure is called a biopsy.

9. Histopathology
• Histopathology is the examination of cells under a
microscope that have been stained with dye to
make them visible or easier to see.
• Often, antibodies are used to label different parts of
the cells with different colors of dye or
fluorescence.
• After the microscope became widespread in
pathology, many different methods of preserving
and dyeing tissue were developed.

10. Cytopathology
• Cytopathology is the study of small groups of
cells shed in bodily fluids or obtained through
scraping, such as those taken during a cervical Pap
smear.
• A Pap smear detects cervical cancer and some
types of infections.
• The cells are taken by swabbing the cervix, and
are then processed and examined under a
microscope to check for abnormalities.

11. Clinical Pathology
• Clinical pathology diagnoses disease through
laboratory analysis of bodily fluids and tissues.
• For example, the chemical components
of blood may be analyzed, along with analyzing
cells and identifying any microorganisms such
as bacteria that are present in a sample.
• Sometimes, the field of clinical pathology is also
referred to as the field of laboratory medicine.
• Major types include the following:

12. Chemical pathology, or clinical
chemistry
• Chemical pathology, or clinical chemistry,
involves the chemical analysis of bodily fluids,
through testing and microscopy.
• Commonly, chemical pathology involves the
study of blood and its immune components like
white blood cells.

13. Hematology
• Hematology is also related to the study of blood,
but it has more to do with identifying blood
diseases specifically than chemical pathology
does.
• Hematologists also study the lymph system and
bone marrow, which are other parts of the
hematopoietic system.

14. Immunology, or immunopathology
• Immunology, or immunopathology, is the study
of immune system disorders.
• It deals with immune responses to foreign
molecules, allergies, immunodeficiencies, and
organ transplant rejection.

15. Molecular Pathology
• Molecular pathology is the study of abnormalities of
tissues and cells at the molecular level.
• It is a broad category that is used to refer to the
study of disease of any organ or tissue in the body
by examining what molecules are present in cells.
• It can combine aspects of both anatomical and
clinical pathology.
• Some techniques that can be used in molecular
pathology include polymerase chain reaction (PCR)
to amplify DNA, fluorescence labeling, karyotype
imaging of chromosomes, and DNA microarrays
(small samples of DNA placed onto biochips).

16. Importance of Pathology
• General knowledge of how disease are caused
• General patterns and classification of diseases
• Evolution of disease from its causes to clinical
presentation
• The signs and symptoms of disease
• Nature, spread and precautions to prevent
common disease
• Know the different disciplines that makeup
pathology
• Better understand the patient and his disease.

17. Application of Pathology in
Laboratory diagnosis
• Understand the problem:
• The study of pathology helps the doctor in the
investigation, interpretive, and management skills
of the pathologists.
• This process helps them understand the cause of
the problem, and accordingly, the doctors work to
obtain the cure.

18. • Place for the experiment: It is often said that the
clinical pathology is the place where the doctor
carries all the experiments. Plus, it is the only
place where all the medicines, vaccines, etc. The
purpose of clinical pathology is very vast and
dynamic.
• Creation of vaccines: The improvement skills
and the pathologists’ management skills help
them create a better future. However, it is
possible by creating medicines or vaccines for
rare diseases.

19. • Cure patient: Clinical pathology works for patients
who get admitted to hospitals. Moreover, to cure
such a patient is the prime objective of the
pathologists. Also, they work for the general patient
population with the help of their investigation skills
and management skills.
• Run analysis: Analyzing clinical data and the
research data is an integral part of the clinical
pathology to obtain a perfect result. Generally, the
result is 100 % effective and lies in the proper
researches. For this purpose, they take the help of
the medicines or any chemicals and the equipment
to conduct any experiments.

20. • Manage lab:
• The pathologists’ most crucial goal here is to
manage a successful laboratory where all the
necessary equipment is present.
• Along with that, there are proper arrangements
of evacuation or availability of first aids in times
of emergencies.
• Keeping an eye on the entire gadget is also a part
of the plan where the pathologists are in charge
of taking care of laboratory gadgets; they need to
inform the higher authority for replacing tools or
lab wears if anything broken.
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