Introduction to Pathology Dr Abdel Monem H Lubbad

Introduction to Pathology Dr. Abdel Monem H. Lubbad , Ph. D, MD Professor of Pathology Faculty of Medicine Islamic University Gaza 2016

Definition of pathology It is the “Scientific study of disease" . "scientific study of the molecular, cellular, tissue, or organ system response to injurious agents. " Pathology serves as a "bridge" or "link" between the preclinical sciences (anatomy, physiology, ……etc. ) and the courses in clinical medicine.

What is the Disease? l It is the “State in which an individual exhibits an anatomical, physiological, or biochemical deviation from the normal” • Disease may be defined as : an abnormal alteration of structure or function in any part of the body.

Basic Language of Pathology In order for a subject or course to be meaningful, one should become familiar with the basic terminology applicable to that subject.

l Pathology is the study of suffering (Latin word ) ! – Logos = study – Pathos= suffering l • Etiology = Cause l • Pathogenesis = sequence of events l • Morphology = structural alterations in cells and tissues l – Gross = Changes in the tissue or organ l – Microscopy = Changes noted under a light microscope

Classification of Diseases: Ø Developmental – genetic, congenital. Ø Acquired: *Inflammatory – Trauma, infections, immune, etc. *Neoplastic – tumors cancers *Degenerative – ageing. *Metabolic. *Iatrogenic: Drug induced.

Branches of Pathology l General Pathology l Systemic Pathology l Gross Pathology l Cellular Pathology l Surgical Pathology l Clinical Pathology l Immunopathology

Learning Pathology: l General Pathology l Common changes in all tissues. e. g. . Inflammation, cancer, ageing, edema, hemorrhage …. etc. l Systemic Pathology l Discussing the pathologic mechanisms in relation to various organ systems e. g. CVS, CNS, GIT…. . etc.

What should we Know About A Disease • • • Definition. Epidemiology – Where & When. Etiology – What is the cause? y g o l Pathogenesis - Evolution of dis. tho a Morphology - Structural Changes. P Functional consequences Management Prognosis Prevention

Pathology focuses on 4 aspects of disease: l ETIOLOGY: Cause of disease. l PATHOGENESIS: Mechanisms of development of disease. l MORPHOLOGY: The structural alterations induced in cell and tissues. l FUNCTIONAL CONSEQUENCES: Functional results of the morphologic changes, as observed clinically.

Etiology “Study of the cause of a disease" Knowledge of etiology remains the backbone of: l Disease diagnosis l Understanding the l Treatment nature of diseases.

Etiology …… l An etiologic agent : is the factor (bacterium, virus, etc. ) responsible for lesions or a disease state. 1 - Predisposing Causes of Disease: Factors which make an individual more susceptible to a disease (damp weather, poor ventilation, smoking , etc. ) 2 - Exciting Causes of Disease: Factors which are directly responsible for a disease (hypoxia, chemical agents…. etc. ).

Etiology Disease l. One etiologic agent • Several etiologic - one disease, as Malaria. agents one disease, as diabetes. Disease • One etiologic agent several diseases, as smoking.

Etiology: What is the cause? Ø Environmental agents: • • • Ø Physical Chemical Nutritional Infections Immunological Psychological Genetic Factors: Age • Genes • Multifactorial: As Diabetes, Hypertension Cancer

pathogenesis The sequence events in the response of the cells or tissues to the etiologic agent, from the initial stimulus to the ultimate expression of the disease, ”from the time it is initiated to its final conclusion in recovery or death” The core of the science of pathology — the study the pathogenesis of the disease.

Morphology: Structural Changes l. Structural changes in disease. l. Tumor in a cancer. l. Ulcer in an infection. l. Atrophy in dementia. Gross & Microscopic.

Technique of Morphology Gross appearance: size, shape weight color consistency surface edge, section

Histologic and cytologic observation: most common and basic formalin fixed → HE (hematoxylin and eosin) stained Hemangioma of ventrical wall

Histochemistry and cytochemistry PAS→BM

Immunohistochemistry 1. Ag-Ab specific reaction 2. Applications (1) Location analysis cytokeratin→cell membrane (2) Clinical diagnosis and distinguishing diagnosis of tumor histogenesis

Leiomyosarcoma Actin (+)

Ultrastructural observation TEM (transmitting electron microscope) Filtering membrane

SEM (scanning electron microscope) Podocyt e

Flow cytometry (FCM) 1. One kind of cells→quantitative 2. DNA ploidy analysis 3. Protein nucleus acid→quantitative analysis 4. Selection of collection of cells

Molecular biology technique 1. Polymerase chain reaction (PCR) 2. DNA sequencing 3. Biochip technique (1) Gene chip (DNA chip) (2) Protein chip (protein microarray) (3) Tissue chip (tissue microarray)

Polymerase chain reaction (PCR)

prognosis l Expected outcome of the disease, It is the clinician's estimate of the severity and possible result of a disease. Robbins Basic Pathology. Page 1