Introduction to Pathology

Introduction to Pathology

• Pathology is the study of the structural, biochemical, and functional changes in cells, tissues, and organs that underlie disease
• The word 'Pathology' comes from two Greek words: pathos (meaning suffering) and logos (meaning study)
• Pathology consists of the abnormalities in normal anatomy (including histology) and normal physiology owing to disease
• ‘Pathophysiology’ combines 'patho' (suffering) and 'physiology' (study of normal function)
• Pathophysiology is the study of disordered function (i.e. physiological changes) and breakdown of homeostasis in diseases (i.e. biochemical changes).

Course Overview

• The course will cover the basic concepts and general mechanisms of cell and tissue reactions and disease processes
• This includes the most common etiological factors, pathogenesis, different morphological features and clinical manifestations
• Topics include cell injury, cellular adaptations, intracellular accumulations, inflammation, regeneration, tissue repair and healing
• The course will also address the most common pathology terminologies that are essential for the course.

Semester 1 Topics

• Cell injury
• Types of cellular adaptations
• Inflammation: Acute, chronic and granulomatous type
• Tissue repair and wound healing

Objectives

• To understand the major cellular and molecular changes which underlies a general disease process
• Apply these concepts into understanding of the specific diseases
• Identifying disease morphologies and outcome and correlating their clinical presentations with the disease process
• To recognize the etiology, pathogenesis and morphology of disease phenomena associated with cell injury, inflammation and tissue repair
• To understand the knowledge of microscopic features of the range of normality within tissues as well as the major common pathological processes and patterns of disease

Assessment

• There are six main assessment components for this course:
  • Quizzes 1 and 2
  • Lab requirements
  • Assignments
  • OSPE
  • Final Exam

Common Terminology in Pathology

• Patient: The person affected by the diseas
• Lesion: The characteristic changes in tissues and cells produced by disease
• Symptoms: Functional implications of the lesion felt by the patient
• Physical Signs: Functional implications discovered by the clinician
• Diagnosis: The clinical significance of the morphologic and functional changes together with results of other investigations help to arrive at an answer to what is wrong
• Prognosis: What is going to happen
• Treatment: What can be done about it (How to treat or manage)
• Prevention: What should be done to avoid complications and spread

Aspects of Disease Process

• Etiology: The cause for a disease (‘WHY’ of a disease)
• Pathogenesis: The mechanisms by which the lesions are produced (‘HOW’ of a disease)
• Morphology: The appearance of tissue or organ in a disease; changes recognized by the naked eye is ‘GROSS’ morphology and changes studied by microscopy is ‘MICROSCOPIC’ morphology
• Clinical Manifestation: Signs and symptoms of the disease

Disease Aspects

• Pathogenesis: The mechanisms by which the lesions are produced.
• Morphology: The structural alterations in cells or tissues that are characteristic of a disease and hence diagnostic of an etiologic process; includes gross and microscopic examination
  • Macroscopical (gross) lesions: Abnormality in the tissue can be described grossly or by the naked eye including location, color, size, shape, consistency & appearance of the cut surface.
  • Microscopy: Abnormal morphological changes described under the microscope.
  • Nonneoplastic lesions: Inflammatory: acute or chronic, Congenital disorders, Endocrine deficiencies, Hyper/Hypo, Infarction, Infections, Intracellular accumulations, Autoimmune diseases
  • Neoplastic lesions: Capsule, circumscription, Tumor cells : benign Vs malignant, If malignant: Histological type, Grade, Margins, Lymphovascular invasion, Status of lymph nodes

Subdivisions of Pathology

• General pathology: Concerned with the common reactions of cells and tissues to injurious stimuli; these reactions are often not tissue specific (e.g. acute inflammation in response to bacterial infections produces a very similar reaction in most tissues)
• Systemic pathology: Examines the alterations and underlying mechanisms in diseases of particular organ systems

Branches of Pathology

• Histopathology (Anatomic Pathology): The study includes structural changes (gross or macroscopic changes), and the changes detected by microscopy, to arrive at the most accurate diagnosis; Modern time anatomic pathology includes sub-specialities such as cardiac pathology, pulmonary pathology, neuropathology, renal pathology, gynaecologic pathology, breast pathology, dermatopathology
• Macroscopic pathology (Gross)
• Microscopic features
  • Surgical pathology: Deals with the study of tissues removed from the living body by biopsy or surgical resection
  • Experimental pathology: Production of disease in the experimental animal and study of morphological changes in organs after sacrificing the animal.
  • Forensic pathology and autopsy work: Includes the study of organs and tissues removed at postmortem for medicolegal work and for determining the underlying sequence and cause of death
• Cytology: Study of cells
  • Exfoliative cytology: Cells shed off from the lesions
  • Fine-needle aspiration cytology (FNAC): Cells aspirated from superficial and deep-seated lesions for diagnosis
• Clinical Pathology: Analysis of various fluids including blood, urine, semen, CSF and other body fluids; such analysis may be qualitative, semi-quantitative or quantitative.

Explore the fundamentals of pathology, focusing on the structural and functional changes in cells, tissues, and organs due to diseases. The course delves into pathophysiology, emphasizing the physiological changes and homeostasis breakdown in various conditions. Gain insights into cell injury, inflammation, and the varied manifestations of diseases.