Human biology and pathology

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

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*

Course contents

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

Lab Work

Nature of Injurious Stimulus Cellular ResponseALTERED PHYSIOLOGICAL STIMULI; SOME NONLETHAL INJURIOUS STIMULI

•Increased demand, increased stimulation (e.g., by growth factors, hormones)•Decreased nutrients, decreased stimulation•Chronic irritation (physical or chemical)

CELLULAR ADAPTATIONS

•Hyperplasia, hypertrophy•Atrophy •Metaplasia

REDUCED OXYGEN SUPPLY; CHEMICAL INJURY; MICROBIAL INFECTION

Acute and transientProgressive and severe (including DNA damage)

CELL INJURY

Acute reversible injuryCellular swelling fatty changeIrreversible injury ➙ cell deathNecrosisApoptosis

Nature of Injurious Stimulus Cellular ResponseMetabolic Alterations, Genetic OR Acquired; CHRONIC INJURY

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

Hypertrophy

Vascular supply Diminished oxidative capability of the

mitochondria Altered protein synthesis and degradation

Limitations of the hypertrophy

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

◦ Hormonal (breast, uterine muscles)◦ Tissue loss (kidney, liver)

Mechanism of hyperplaia is by mitotic division

Hyperplasia

Normal myocyte

Hypertrophied myocyte

Adaptation 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

Atrophy

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

Mechanism of atrophy

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

Metaplasia

Chronic irritation Chronic inflammation Vit A deficiency

Examples Epithelial metaplasia

◦ Columnar to squamous metaplasia (trachea, bronchi) .

◦ Atypical metaplasia.

Causes

Histology of trachea