PATHOLOGYDr. Ziyad Ahmed
The principle goal of the third year pathology course in medical schools is understanding of the mechanisms of disease (pathogenesis) as a foundation of dealing with a fast amount of clinical information the students will encounter in later clinical years
The Principle Objectives
To use pathology to facilitate medical education
Understanding mechanisms is more a function of logic than of a memory
To leave students with lasting knowledge of pathology
To use pathology as the scientific basis of the art of medicine
REQUIRED TEXTSBasic Pathology Robbins
What Is PathologyDefinition:
Pathos= suffering ------ Disease
Logos = study
Pathology is study diseases by scientific methods.
A disease is an abnormal variation in the structure and/or function of any organ in the body
Examples of diseases
Pneumonia: Inflammation of the lung. There are structural changes in the lung and disturbance of function of respiration
Pathology focuses on 4 aspects of diseaseETIOLOGY:--
Mean the cause of the disease e.g. bacterial infection of the lung causes pneumonia, cut of blood supply by the coronary artery causes infarction of the heart
Mean the mechanism of development of a disease. E.g. in viral infection the virus proliferates inside the cell leading to rupture of the cell. While bacteria release toxin which destroy cells
The core of the science of pathology the study the pathogenesis of the disease.
The structural alterations induced in cells and tissues.
Gross = Changes in the tissue or organ (by the naked eye)
Microscopy = Changes noted under a light microscope
Functional consequences of the morphologic changes, as observed clinically (Signs & Symptoms).
Knowledge of etiology remains the backbone:
Understanding the nature of diseases
Treatment of diseases.
Pathology Subspecialties*Cellular pathology including
The excised tissue is examined grossly (by the naked eye ) for any change in size, shape, color,
Microscopic examination by light or electron microscope for any structural changes
Smear (i.e. cells put on slides) are examined for any cellular changes. e.g. cervical smear, bronchial brush, sputum cytology
concerned with medicolegal postmortem examinations.
the study of infectious diseases and their causes. This can be subdivided into bacteriology, virology, mycology and protozology.
the laboratory study of diseases of the blood.
*Chemical pathology or clinical biochemistry
is the study of body chemistry, usually by assaying the levels of substances ( electrolytes, enzymes, lipids, trace elements) in the blood or urine.
is the study of host defenses against external threats in addition to study of autoimmunity.
the study of inheritance of characteristics and of diseases, or predisposition to diseases
Why study pathology?#A bridging discipline between basic science and clinical practice.
#To understand the mechanisms of symptom production i.e. help in interpretation of signs and symptom of diseases
Understand the biochemical changes#
Provides a reason or rational for treatment choices#
#To intelligently communicate with professional colleagues
So that you can correctly explain things to your patients#
#Recognize the need for self-directed, independent reading of journals, texts and other sources
PATHOLOGY could be defined as the specialty that employs morphological techniques to explain symptoms and signs, to determine the cause of death, to guide therapy, and to predict the evolution of disease.
The process of bringing about resolution of suffering
An individual skilled in the art of healing
Piece of tissue taken from living body. e.g. gastric biopsy ,colonic biopsy
Piece of tissue taken from dead body during post mortem examination
Digestion of the tissue by its own enzymes
Mean the outcome of the disease. Is it curable or Is it fatal ?
PreventionWhen you know the cause & the pathogenesis, you can plan for prevention of the disease by isolation or vaccination .
Types of diseasesCongenital :
mean develop during intrauterine life e.g. congenital heart diseases.
Mean after birth. e.g. all infections, tumors ...
Causes of diseases1.Genetically determined:
due to changes in the gene either due to change in the DNA or the number or sites of the chromosomes. e.g. trisomy chromosome 21 in mongolism.
due to the effects of the environment.
Causes of acquired diseases1.Deficiency disease: e.g. Vit.B12 deficiency
2.Infections: e.g. Tonsillitis.
3.Physical agents: e.g. burn. Trauma etc
4.Chemical agents: all toxin , drugs etc.
5.Immunological: e.g. rheumatic fever
6. Psychological causes. e.g. depression.
How to deal with biopsyThe biopsy should be fixed in proper fixative like 10% formalin. put in proper container and sent to the lab.
Note: formalin or any fixative is used to prevent autolysis.
How is pathology detectedOr how do you find it
SEARCH BY USING YOUR CLINICAL SKILLS
Signs & Symptoms
Divisions-Pathology Generalstudy basic reactions of cells and tissues to abnormal stimuli that
underlie all diseases - common changes in all tissues; e.g., cancer, aging, inflammation
- study of the particular responses of specialized organs and tissues
to well-defined stimuli -specific changes in organs; e.g., goiter, breast cancer.
ExaminationsThere will be an examination after each chapter and each exam will be comprehensive over the previous exams
The last or final examination, will obviously be comprehensive
Examinations may be composed of short answer, listing, short discussion, multiple choice, or matching type questions.
Classroom StuffStudents are expected to attend the lectures. The primary purpose of the
lectures is to present and review the most important aspects of the
respective subject material.
The lectures are not intended to be all encompassing in regards to the material.
The student is expected to read the material in the designated textbook.
Be prepared to learn what a doctor is supposed to know
Ask questions and answer questions
Participate in class