PATHOLOGY RESOURCE

 

PATHOLOGY

• Patho (disease, misery) and logy (study of, reasoning about)

• Pathology is study of disease.

• More appropriately is study of morphological, functional or biochemical changes in cells, tissues or fluids of the body

From the ancient times till now there has been a mammoth increase in the knowledge about disease which has gone from macro to micro level

• Pathology is study of appreciating something wrong in the body which for the student is what,

• further questions then arise that why and how this wrong has happened or developed

• The subject of GENERAL PATHOLOGY (a branch of pathology) revolves around the mechanisms by which tissues are injured together with the expressions of injury and the functional consequences of it,

BRANCHES OF PATHOLOGY

• Medical Pathology deals with study of disease in man,

• Veterinary Pathology deals with study of disease in animals.

• Diagnostic Pathology deals with identification of nature of disease using traditionally, gross or histopathological  (microscopic pathology) tools but now a days other tools are also used in the subject.

• Forensic Pathology deals with medicolegal issues, e.g., ruling of death of animals by poisoning in which case court or police department is involved.

• Surgical Pathology deals with study of biopsy material (tissue taken during operation).

• Environmetal Pathology deals with study of effects of environment in the causation of disease or impact of environment on disease 

• Toxicological pathology deals with study of effects of different toxic substances in the causation of disease.

• Zoo and Wild life Pathology deals with diseases in zoo and wild animals, respectively.

• Immunopathology is a branch of pathology that deals with tissue injury produced by the involvement of immune system of the body.

• Clinical Pathology deals with laboratory analysis of disease including haematology, cytology, serum chemistry, endocrinology, urinalysis etc.

• Experimental Pathology deals with experimental study of diseases that may involve experimental production of disease and then study of different abnormalities produced thereto.

• General pathology is the branch of pathology that deals with common denominators (lesions) of disease and mechanism of production of these.

• Systemic pathology is a branch of pathology that deals with study of diseases with reference to system of involvement and is sometimes also named special pathology.

 

LANGUAGE OF PATHOLOGY

• Lesion is a term used to denote an abnormality and mostly sound for any structural abnormality but rarely is used to describe the functional abnormality or biochemical lesion. The examples includes abscess, extra growth, change or missing enzyme or biochemical etc.

• Pathognomonic is a term which means that a particular abnormality is found only in specific condition, e.g., hearing the fetal heart tone is pathognomonic of pregnancy.

• A biopsy is tissue or peace of tissue removed from an animal during life for diagnostic purpose. This is mostly obtained to make clear a suspected cancerous from non-cancerous outgrowths

• The autopsy  ("necropsy") is the opposite of "biopsy". It means a pathologist examines part or all of a dead body by doing postmortem. The term autopsy is used in human discipline, while necropsy is used in veterinary discipline with same meaning.

• The Disease can simply be described by breaking the word into two, i.e., dis and ease which is self explanatory. However, disease is term used to describe clinically apparent dysfunction due to abnormalities, excesses, deficiencies, and injuries occurring at the cell and tissue level.

• Pathogenesis is a term used to describe the mechanism of development of disease and involves step-by-step progression of disease.

• Diagnosis means naming a disease on the basis of clinical signs, laboratory test and lesions characteristics of disease , e.g., pericarditis and perihepatitis (lesions) in poultry are very much characteristic of colibacillosis (disease).

• Prognosis is a term used to designate the possible outcome of disease whether favourable or unfavourable or in other words good or poor.

• Aetiology refers to cause of disease that may be due to intrinsic or extrinsic reasons, e.g., tuberculosis is caused by Mycobacterium (bacteria).

• Clinical signs and symptoms: signs are evidence of disease discovered by the physician and are used to describe abnormal behaviour by animals as exhibited by them due to disease, e.g., higher temperature, staggering gait, yellow discolouration of eyes and mucus membranes.

• A syndrome is a cluster of symptoms and/or signs not necessarily due to the same cause. e.g., malabsorption syndrome.

 

TOOLS OF PATHOLOGY

• Eyes and Hands

• Light Microscope

• Histochemical Stains — Fat - Oil red O, Best Carmine - Glycogen, Acid Fast - Mycobacterium etc.

• Darkfield, Phase Contrast, Fluorescence microscopy

• Electron Microscopy

  • Transmission - thin Sections

  • Scanning - Three dimensional structure

• Photometers / Colourimeters etc.

NORMAL   ----   ADAPTATION   --- INJURY