 ◦ Definition It is combination of two Latin words ◦ Pathos meaning disease ◦ Logos meaning study Pathology is a branch of medicine that deals with the nature of disease.

the study of the structural, biochemical, and functional changes in cells, tissues, and organs that underlie disease

 ◦ ◦ General pathology reactions of cells and tissues to abnormal stimuli reactions of cells and tissues to abnormal stimuli  ◦ Systemic pathology alterations in specialized organs and tissues that are responsible for disorders that involve these organs

   

Etiology

(cause)

Pathogenesis

(mechanisms of its development )

Molecular and morphologic changes

(biochemical and structural alterations induced in the cells and organs of the body)

Clinical manifestations

(functional consequences of these changes)

          Basic Molecular Biology Basic Pathology* Principles and practice of molecular pathology* Molecular Biology of the Cell Concepts in molecular biology Concepts in genetics Understanding molecular pathogenesis* Clinical pathology* Introduction to Bio-Informatics Applied Comparative Pathology*

      Clinical proteomics and molecular pathology* Integration of molecular and cellular pathogenesis* Molecular pathology of human diseases* Molecular basis of diseases of pathology of immunity* Infection and host response* Molecular mechanism of cell death *

        Modern Drug Discovery Technologies Practical Histopathology and Mouse Models of Human Disease Microbial pathogenesis* Modern Methods in Molecular Pathology* Molecular Pathology of Cancer* Biological Therapies Molecular diagnosis of Infection The human epigenome

       DNA Extraction RNA extraction Blood group Test Blood Sugar test PAGE Histopathology ELISA Immuno Histochemistry

Nature of Injurious Stimulus ALTERED PHYSIOLOGICAL STIMULI; SOME NONLETHAL INJURIOUS STIMULI Cellular Response CELLULAR ADAPTATIONS • Increased demand, increased stimulation (e.g., by growth factors, hormones) • Decreased nutrients, decreased stimulation • Chronic irritation (physical or chemical) REDUCED OXYGEN SUPPLY; CHEMICAL INJURY; MICROBIAL INFECTION Acute and transient Progressive and severe (including DNA damage) • Hyperplasia, hypertrophy • Atrophy • Metaplasia CELL INJURY Acute reversible injury Cellular swelling fatty change Irreversible injury ➙ cell death Necrosis Apoptosis

Nature of Injurious Stimulus Metabolic Alterations, Genetic OR Acquired; CHRONIC INJURY Cellular Response Intracellular Accumulations; CALCIFICATION Cumulative Sublethal Injury over long life span CELLULAR AGING

 Hypertrophy refers to an increase in the size of cells, resulting in an increase in the size of the organ.

   ◦ ◦ ◦ ◦ Synthesis of more structural proteins May be physiological Breast and uterus LVH Skeletal muscle Pathological Uterus under influence of estrogen secreted by ovarian cancer

   Vascular supply Diminished oxidative capability of the mitochondria Altered protein synthesis and degradation

 Hyperplasia is an increase in the number of cells in an organor tissue, usually resulting in increased volume of the organ or tissue.

◦ ◦ Hormonal (breast, uterine muscles) Tissue loss (kidney, liver) Mechanism of hyperplaia is by mitotic division

Adaptation Hypertrophied myocyte Normal myocyte Reversible cell injury Cell death

 Atrophy is reduced size of an organ or tissue resulting from a decrease in cell size and number   ◦ ◦ ◦ Physiological ◦ Decreased workload ◦ Inadequate nutrition ◦ Aging Pathological Loss of innervation Loss of endocrine stimulation Diminished blood supply

  Increased degradation or decreased synthesis of cellular proteins Hormones (insulin, thyroid hormones, glucodorticoids and prostaglandins)        Examples of atrophy Thymus atrophy Gonadal atrophy with age Starvation Disuse atrophy Denervation Diminished blood supply Pressure

 Metaplasia is a reversible change in which one differentiated cell type (epithelial or mesenchymal) is replaced by another cell type  an adaptive substitution of cells that are sensitive to stress by cell types better able to withstand the adverse environment

   Chronic irritation Chronic inflammation Vit A deficiency   Examples ◦ ◦ Epithelial metaplasia Columnar to squamous metaplasia (trachea, bronchi) .

Atypical metaplasia.