This lecture provides an introduction to pathology. It defines pathology as the study of disease and morphological, functional, molecular and biochemical changes that occur in response to injury. It discusses the main divisions of pathology including general pathology, systemic pathology, clinical pathology and necropsy practices. Key points covered include defining lesions, gross and microscopic examination, and the four aspects of a disease process - etiology, pathogenesis, morphological changes and functional alterations. The goal of pathology is to better understand diseases to aid in diagnosis and treatment.

1. LECTURE NO.1
Introduction to Pathology

2. Learning Outcomes
• By the end of the lecture you should be able to:
• Define Pathology in two ways
• Define General Pathology
• Discuss about the Morphological Changes
• Explain lesion and types of the Lesion
• Define Gross examination and Histopathology
• Four aspects of a disease process

3. Introduction to Pathology
•Pathology:
• Pathology is the study of Disease.
• Pathos – suffering, disease
• Logos – study
Disease?
*loss of ease
*a departure from a
normal state
The better we understand the disease, the better we
can diagnose & treat it
Objective?

4. What‘s normal (When Body At Ease)
Anatomy
Physiology
Histology
Biochemistry
Genetics
Health is a state of an
individual living in
complete harmony with
his environment.

5. Pathology is the study of morphological,
functional, molecular and biochemical
CHANGES in cells, tissues, or organs in response
to an INJURY
Now! Let’s define again
Cell damage is cell injury

6. Courses
General Vet.
Pathology
Systemic Vet.
Pathology
Clinical Pathology
Necropsy
Practices
&
Meat inspection
Poultry Pathology

7. Pathology
General
Pathology
Concerned with the
basic reactions of
cells and tissues to
injurious stimuli
Systemic
Pathology
The application of
these basic reactions
to the various body
systems, or to various
specific diseases

8. Pathology
Clinical
Pathology
It includes certain laboratory
methods which help in making
the diagnosis e.g. urine
examination, blood
examination etc
Necropsy &
meat
inspection
Postmortem examination of
animals.
To determine the health of
animals both prior to death
(ante mortem) and after death
(post mortem)

9. Pathology covers Four aspects of a disease
process
Aetiology ( cause of
disease)
Pathogenesis
Morphological Changes
(Lesions)
Functional alterations and
changes (Pathophysiology)
1 Etiology: Etiology of a disease
means the cause of the disease,
when the cause is unknown it is
called idiopathic etiology.
2 Pathogenesis: Mechanism of
development of a disease.

10. Agents (Aetiology) that cause things to go wrong/
injury
Physical
Environmental
Microbial
Nutritious
Genetic
Chemicals
Parasitic

11. 3 Morphological Changes (Lesion)
The structural
alterations in cells or
tissues
A lesion is any
damage or abnormal
change in the tissue
structure of an
organism, usually
caused by disease
Morphology: study of forms and structures

12. Types of Lesion
Macroscopic or Microscopic morphological alteration occurring
in the tissue structure or function as the result of injury
Macroscopic or Gross Lesions
Can see through the naked eye
Gross Pathology/Examination
Examination of tissue without the
help of a microscope
Microscopic or histopathology
Lesions
Can see through a microscope
Histopathology
Study of diseases tissue under a
microscope
Let’s define again the lesion

13. Gross Lesion)
Multifocal Granulomas

14. Microscopic Lesion
Granuloma

15. Pathognomonic Lesion: A lesion or sign that is specifically
distinctive or characteristic of a disease or pathological condition.
4 Functional alterations and changes
The morphological changes will lead to functional alterations to
produce the clinical signs & symptoms of the disease.
Sign: Objective, seen by observer or clinician.
Symptom: Generally subjective, experienced & described by
patient.

16. Two main divisions of Pathology
ANATOMICAL (Anatomic) Pathology: The diagnosis of the disease based
on the Gross examination (Gross pathology), Microscopic examination
(Histopathology), Molecular examination of organs tissues (Molecular
pathology), Dead bodies examination (Necropsy).
Include General Pathology and Systemic Pathology
CLINICAL Pathology: The diagnosis of the disease based on
the laboratory analysis of bodily fluids (blood, urine, tissue aspirates)
using the tools of chemistry and hematology.
Forensic pathology: determining cause of death, usually for criminal law cases and
civil law cases in some jurisdictions.

17. In summary, pathology
studies: etiology,
pathogenesis, morphological
changes, clinical features,
diagnosis and prognosis of all
the diseases.
Thanks
Dr Rukhshanda
Ramzaan
RcVet Lahore