Basic Pathology Introduction

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Questions and Answers

What are the two apparent difficulties that face the new student of pathology?

language (terminology) and process

Why do students need to learn the vocabulary of special terms in pathology?

Because it is the language of pathology

Because it is the language of clinical medicine

Both a and b (correct)

None of the above

The term 'hyperplasia' means an increase in the size of an organ due to the proliferation of its constituent cells; this definition must be learnt before the student attempts to learn about the process of ________.

hyperplasia

Providing the basic concepts of cell injury, inflammatory and repair processes, circulatory disorders, infections, cell growth and differentiation, and neoplasia are objectives of the course.

True Signup and view all the answers

Define pathology.

Pathology is the study of diseases by scientific methods. Signup and view all the answers

Who is considered the father of modern pathology?

Rudolf Virchow Signup and view all the answers

Pathology can be classified into General Pathology and Clinical Pathology.

False Signup and view all the answers

______ is the branch of pathology that involves studying tissue biopsies to diagnose diseases.

Histopathology Signup and view all the answers

Match the pathology branch with its description:

Histopathology = Study of tissue biopsies for disease diagnosis Cytopathology = Study of cell morphology for disease diagnosis Immunohistochemistry = Special staining to detect antigens in tissues Hematology = Study of blood and bone marrow for hematolymphoid disorders Signup and view all the answers

What is the definition of metaplasia?

Reversible change in cell type Signup and view all the answers

What can cause squamous metaplasia in the respiratory epithelium?

Vitamin A deficiency and cigarette smoking Signup and view all the answers

Columnar cells are replaced by cells in metaplasia.

squamous Signup and view all the answers

Match the metaplasia type with its description:

Squamous metaplasia = Replacement of columnar cells by squamous cells Columnar cell metaplasia = Replacement of squamous lining by columnar cells Osseous metaplasia = Formation of new bone at tissue injury sites Myeloid metaplasia = Proliferation of hematopoietic tissue outside bone marrow Signup and view all the answers

What is the difference between hypertrophy and hyperplasia?

Hypertrophy is an increase in cell size, while hyperplasia is an increase in cell number. Signup and view all the answers

What is metaplasia?

Metaplasia is a reversible change from one adult cell type to another. Signup and view all the answers

Is hyperplasia reversible?

True Signup and view all the answers

Hypoplasia refers to a decrease in the __________ of cells in an organ or tissue.

number Signup and view all the answers

Study Notes

Introduction to Pathology

Definition of Pathology: the study of diseases by scientific methods
Pathology is literally the study (logos) of suffering (pathos)
The ultimate goal of pathology is the identification of the causes of disease, leading to disease treatment and prevention

History of Pathology

Prehistoric time to AD1500: religious beliefs and magic to rational approach
Key figures: Hippocrates, Galen, Avicenna, Al-Razi, and Al-Zahrawy
AD1500-1800: Human Anatomy to Era of Gross Pathology
- Renaissance: Leonardo da Vinci, Vesalius, and Fallopius
- Leeuwenhoek, Malpighi, and Morgagni
1800-1950: Technology Development & Cellular Pathology
- Louis Pasteur, Hansen, Ehrlich, and Gram
- Romanowsky, Koch, and May-Grunwald
Rudolf Virchow: father of modern pathology, stated the cellular pathology concept

Virchow's Hypothesis

Diseases can be defined by observing morphologic changes in cells
Implication: diseases can be understood by studying cellular changes

Normal Homeostasis

The body maintains a steady state (homeostasis) through continuous monitoring and adaptations
Normal homeostasis is achieved by genetic programs, metabolism, proliferation, and differentiation

Pathology

Pathology is the study of diseases by scientific methods
Pathology is dynamic, with new findings constantly changing and expanding our understanding of diseases
In medicine, diseases are studied under the following headings:
- Definition
- Epidemiology
- Etiology (Why?)
- Pathogenesis (How?)
- Morphology (What?)
- Clinical features/presentation
- Investigations
- Treatment and management
- Prognosis

Classification of Pathology

According to range of study: General (Basic) Pathology and Systemic (Specific) Pathology
According to uses and practice field: Experimental Pathology, Clinical (Diagnostic) Pathology

Methods Used in Pathology

Morphologic: Gross observation, Microscopic examination (histo & cyto pathology)
Molecular/Biochemical/Cytogenetic: Applied clinical and research methods
Immunologic/Serologic: Serum, plasma, cell suspensions, tissues
Microbiologic: Cultures, biochemical assays, immunologic

Branches/Subdivisions of Pathology

Histopathology: study of tissue biopsied/excised from the body to diagnose diseases
Cytopathology: study of cell morphology, exfoliated or aspirated from the body to diagnose diseases
Immunohistochemistry: special staining procedure to detect special antigens in the tissue
Hematology: study of blood, blood cells, and bone marrow
Chemical pathology/Clinical biochemistry: study and diagnosis of disease from chemical changes in tissues and fluids
Microbiology: study of infectious diseases and diagnosis of causative organisms
Immunology: study and analysis of the immune system of the body
Toxicology: study of various poisonous and toxic substances
Cytogenetics (Clinical Genetics): study of chromosomes and genes abnormalities
Molecular Pathology: e.g. fluorescent in situ hybridization, Southern blot tests
Autopsy (Forensic Pathology): sub-specialty of pathology that involves examining a dead body

Importance of Pathology

Pathology is an essential part of medical education and practice
Pathology gives clinical purpose to basic sciences and scientific research
Pathology provides diagnostic services for all other medical specialties
"As is our pathology, so is our practice." - Sir William Osler

Adaptations and Accumulations

Cellular Responses: Cells respond to modest changes (stress and injuries) by functional and structural adaptations.
Types of Adaptations:
- Hypertrophy: Increase in size of cells or organs due to increased demand or stimulation.
- Hyperplasia: Increase in the number of cells in an organ or tissue due to increased demand or stimulation.
- Atrophy: Decrease in size of cells, tissues, or organs due to decreased demand or stimulation.
- Metaplasia: Reversible change in which one mature cell type is replaced by another mature cell type, better able to withstand a chronic adverse environment.

Hypertrophy

Physiologic Hypertrophy: Appropriate cellular proliferation to maintain normal function, e.g., lactating breast, uterus in pregnancy.
Pathologic Hypertrophy: Inappropriate cellular proliferation, e.g., cardiac concentric left ventricular hypertrophy due to chronic hemodynamic overload.
Mechanism: Increased cell size due to synthesis of more structural components, especially intracellular proteins.

Hyperplasia

Physiologic Hyperplasia: Appropriate cellular proliferation to maintain normal function, e.g., breast hyperplasia in pregnancy, compensatory hyperplasia in liver.
Pathologic Hyperplasia: Inappropriate cellular proliferation, e.g., endometrial simple hyperplasia, endometrial complex hyperplasia with atypia.
Mechanism: Increased number of cells due to excessive hormonal stimulation or growth factor action.

Atrophy

Physiologic Atrophy: Decrease in size of cells, tissues, or organs due to decreased demand or stimulation, e.g., loss of hormone stimulation in menopause.
Pathologic Atrophy: Decrease in size of cells, tissues, or organs due to disease or injury, e.g., disuse, denervation, ischemia, pressure.
Mechanism: Combination of decreased protein synthesis and increased protein degradation, and increased autophagy.

Metaplasia

Definition: Reversible change in which one mature cell type is replaced by another mature cell type, better able to withstand a chronic adverse environment.
Types of Metaplasia:
- Epithelial Metaplasia: e.g., squamous metaplasia in respiratory epithelium, intestinal columnar metaplasia in esophagus.
- Mesenchymal Metaplasia: e.g., osseous metaplasia, chondroid metaplasia, myeloid metaplasia.
Mechanism: Reprogramming of stem cells in basal layer of epithelium or of pluripotent mesenchymal cells in connective tissue, causing them to differentiate along a new pathway.

Clinical Significance

Metaplasia: Can lead to functional deficits, dysplastic changes, and progression to cancer in metaplastic epithelium.
Adaptations: Can be reversible, but persistent stimuli can lead to malignant transformation.

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Description

This quiz covers the basics of pathology, including its historical background, key concepts, and terminology used to study disease. It also explores the role of pathology in understanding disease.