Difference between revisions of "General Pathology"

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==An Introduction to General Pathology==
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#REDIRECT[[:Category:General Pathology]]
 
 
* The term '''pathology''' is derived from:
 
** '''Pathos''', or suffering
 
** '''Logos''', or reasoning/logic.
 
* Pathology is defined as the study of disease including:
 
** '''Aetiology''' - causal factor(s)
 
** '''Pathogenesis''' - the development of the disease within the body.
 
** '''Lesions''' - the observable structural changes in the tissues and fluids of the body.
 
** '''Pathophysiology''' - the functional changes in diseased tissues.
 
** '''Sequel''' - the consequences of the disease in the body.
 
** '''Remote effects''' - the effect of disease in one tissue on other tissues in the body.
 
 
 
===Lesions===
 
 
 
* Lesions are the abnormalities or changes seen in living tissues due to disease.
 
* Observed in
 
** The live animal
 
** Tissues surgically removed from the live animal
 
*** Biopsy/ excision
 
** Animals soon after death
 
*** Necropsy, post-mortem examination.
 
 
 
====Decription of Lesions====
 
 
 
* Descriptions of lesions is very important
 
* Whole organs, tissues or individual lesions are described under headings such as
 
*# Size
 
*# Shape
 
*# Colour
 
*# Weight
 
*#* Generally in relation to body weight
 
*# Texture and Consistency
 
*# Appearance of the cut surface
 
*# Contents of hollow organs
 
*# Position, relationships and effects on adjacent tissues
 
 
 
*'''See [[General Pathology - Recognition and Description of Lesions|Recognition and Description of Lesions]]'''
 
 
 
===Disease===
 
 
 
====Definition and Type====
 
 
 
* '''Disease''' is  a definite morbid (illness producing) process, having a characteristic train of symptoms or signs.
 
** May affect the whole body or any of its parts.
 
** The disease's aetiology, pathology and prognosis may be known or unknown.
 
* There are two main categories of disease.
 
*# '''Acute'''
 
*#* Characterised by sudden onset and short duration.
 
*#* The outcome of acute disease may be:
 
*#** Death
 
*#** Resolution due to host defence response or clinical therapy
 
*#** Progression to chronic disease
 
*# '''Chronic'''
 
*#* Characterised by insidious onset and protracted course.
 
*#* The outcome of chronic disease may be:
 
*#** Progressive destruction of tissue
 
*#*** Compromises funtion and  endangers life,
 
*#** The halting of the course of disease, with tissue repair by scarring.
 
 
 
====Factors Involved in the Development of Disease====
 
 
 
* There are three factors which conspire with each other to produce disease.
 
*# '''The individual animal'''.
 
*#* In particular, the animal's nutritional and immune status
 
*#** This is modified by:
 
*#*** Recent or concurrent disease
 
*#*** Previous exposure to the agent(s) responsible
 
*# '''The disease-causing agent(s)'''.
 
*#* Most do not cause a uniform pattern of disease
 
*#** Host defences are important in determining the presentation of the disease.
 
*#* An agent's capacity to produce disease depends upon:
 
*#** The dose
 
*#** The virulence of the agent
 
*#* Several agents may be involved.
 
*#** Usually one agent debilitates, allowing others to exert a greater effect within the body
 
*#* The presence of an agent does not necessarily mean it is the cause of the disease!
 
*#* A pathogenic agent may be absent from the tissues, due to:
 
*#** Clinical therapy
 
*#** Host defence systems
 
*# '''Environment''', for example:
 
*#* Overcrowding of animals
 
*#* Mixing animals from differing origins
 
*#** Carriers are allowed to infect susceptible animals.
 
*#*** Carriers are animals which harbour the pathogenic agent but do not show signs of disease.
 
*#* Changes in management routine
 
 
 
====Types of Agents Causing Disease====
 
 
 
# '''Infectious organisms'''
 
#* [[Viruses|Viruses]]
 
#* [[Bacteria|Bacteria]]
 
#* [[Fungi|Fungi]]
 
#* [[Parasites|Parasites]]
 
# '''Physical'''
 
#* Trauma
 
#* Pressure
 
#* Heat
 
#* Cold
 
#* Radiation
 
# '''Chemical'''
 
#* Toxic organic and inorganic substances
 
#* Toxins produced by infectious organisms
 
# '''Nutritional'''
 
#* Deficiencies of vitamins and trace elements
 
#* Excess vitamins and trace elements
 
# '''Genetic defects'''
 
#* There is a very wide range of potential defects.
 
#** Some are incompatible with life
 
#** Others affect specific systems within the body
 
 
 
====Aspects of Disease====
 
 
 
* There are many aspects of a disease that must be considered in order to understand it in full.
 
*# '''Incidence'''
 
*#* How much of the disease is present?
 
*#* Where is the disease found?
 
*#* In what species is the disease seen?
 
*# '''Aetiology'''
 
*#* Causal agent(s)
 
*#* Predisposing factors
 
*# '''Transmission'''
 
*#* How is the disease spread between individuals?
 
*#* Is the disease zoonotic?
 
*# '''Pathogenesis'''
 
*#* How the causal agent(s) exert their effect within the body.
 
*# '''Diagnosis'''
 
*#* History
 
*#* Clinical findings
 
*#** Clinical examination
 
*#** Clinical pathology
 
*#* Biopsy or post-mortem examination
 
*# '''Prognosis and Treatment'''
 
*# '''Control and Prevention'''
 
*#* The ideal situation
 
 
 
====Post-Mortem Examination====
 
 
 
* Post-mortem examination (PME) investigates the observable structural changes in the animal.
 
* Information relating to the disease withing the body or specific tissue is gained from PME.
 
** This includes information on the disease's
 
*** Aetiology (cause).
 
*** Pathogenesis (development).
 
* Several types of changes are encountered at post-mortem examination.
 
*# Those due to the '''disease'''
 
*#* Lesions
 
*# Those occuring '''immediately prior to death'''
 
*#* Agonal
 
*# Those occuring '''after death'''
 
*#* Post-mortem
 
 
 
====Techniques Involved in Pathological Examination====
 
 
 
* '''Fluid examination'''
 
** E.g. blood, urine, discharges from orifices and so on.
 
* '''Cytology'''
 
** Examination of cells in smears, aspirates and fluids.
 
* '''Necropsy'''
 
** Visual examination of the gross changes in the dead body.
 
* '''Histopathology'''
 
** Microscopic examination of:
 
*** Tissues selected from the dead body after necropsy.
 
*** Biopsy/excision materials from lesions in the living animal.
 
* '''Histochemistry'''
 
** Microscopic visualisation of enzymatic activity in tissues.
 
* '''Immunological methods'''
 
** Specific antibody activity can be detected in tissues and fluids.
 
*** Examination of serum can show prior exposure to a particular infectious agent (i.e. specifice antibodies).
 
** Specific antigens can be detected in tissues.
 
*** When linked to a marking agent (e.g. a fluorescent dye), an antibody can localise its antigen in the tissue.
 
* '''Electronmicroscopy'''
 
** Electronmicrosopcy shows fine detail of the surfaces or internal structures of cells.
 
* '''Bacteriology/ Virology/ Parasitology'''
 
** These techniques allow the isolation and identification of pathogenic bacteria, viruses and parasites.
 
* '''Toxicology'''
 
** Analysis of tissues for particular poisons and toxins.
 
 
 
==General Pathology - Contents==
 
 
 
===[[General Pathology - Recognition and Description of Lesions|Recognition and Description of Lesions]]===
 
 
 
===[[General Pathology - Degenerations and Infiltrations|Degenerations and Infiltrations]]===
 
 
 
===[[General Pathology - Necrosis|Necrosis]]===
 
 
 
===[[General Pathology - Post-Mortem Change|Post-Mortem Change]]===
 
 
 
===[[General Pathology - Pigmentation and Calcification|Pigmentation and Calcification]]===
 
 
 
==Pigmentation and Calcification==
 
 
 
===Exogenous Pigmentation===
 
====Carbon (Anthracosis)====
 
====Pneumoconiosis====
 
====Carotenoids====
 
 
 
===Endogenous Pigmentation===
 
====Melanin====
 
====Blood Pigments====
 
=====Haemoglobin=====
 
=====Haemosiderin=====
 
=====Haematin=====
 
=====Jaundice=====
 
=====Haematoidin=====
 
=====Porphyria=====
 
====Lipofuscin====
 
 
 
 
 
===Mineralisation===
 
 
 
====Calcification====
 
=====Dystrophic=====
 
=====Metastatic (Hypercalcaemia)=====
 
 
 
==Circulatory Disorders==
 
 
 
===Introduction====
 
 
 
====Venous Congestion and Hyperaemia====
 
 
 
====Oedema====
 
 
 
 
 
====Dehydration====
 
 
 
====Shock====
 
 
 
====Haemorrhage====
 
=====Rhexis=====
 
=====Diapedesis=====
 
 
 
====Haemostasis====
 
 
 
====Thrombus====
 
=====Causes=====
 
=====Evolution=====
 
=====Embolism=====
 
=====Post Mortem Clots=====
 
 
 
====Disseminated Intravascular Coagulation====
 
 
 
==Inflammation==
 
 
 
===Cardinal Signs===
 
 
 
===Causes===
 
 
 
===Acute===
 
====Introduction====
 
====Sequence of Events====
 
====Fluids====
 
=====Serous=====
 
=====Catarrhal=====
 
=====Fibrinous=====
 
=====Diptheritic=====
 
=====Haemorrhagic=====
 
=====Purulent=====
 
=====Functions of Exudate=====
 
=====Sequel to Exudation=====
 
====Cells====
 
=====Neutrophils=====
 
=====Eosinophils=====
 
=====Mast Cells=====
 
=====Basophils=====
 
 
 
===Chronic===
 
====Introduction====
 
====Cells====
 
=====Macrophages=====
 
=====Lymphocytes=====
 
====Types====
 
=====Granulomatous Inflammation=====
 
=====Granulation Tissue=====
 
=====Lymphocytic Inflammation=====
 
 
 
===Changes in Inflammatory Cells Circulating in Blood===
 
====Neutrophilia====
 
====Neutopenia====
 
====Eosinophilia====
 
====Eosinopenia====
 
====Lymphocytosis====
 
====Lymphopenia====
 
====Plasma Cells====
 
====Monocytosis====
 
 
 
===Role of The Lymph Node in Inflammation===
 
 
 
===Healing and Repair===
 
====Introduction====
 
====Repair====
 
=====Regeneration=====
 
=====Replacement=====
 
====In Particular Tissues====
 
=====Skin=====
 
======First Intention======
 
======Second Intention======
 
=====Bones=====
 
=====Respiratory Tract=====
 
=====Alimentary Tract=====
 
=====Urinary Tract=====
 
=====Genital Tract=====
 
=====Central Nervous System=====
 
 
 
==Growth Disorders==
 
 
 
===Congenital===
 
====Causes====
 
====Malformations====
 
=====Cyclops=====
 
=====Bulldog Calf=====
 
=====Cleft Palate=====
 
=====Cystic Kidney=====
 
=====Spina Bifida=====
 
=====Hydrocephalus=====
 
=====Cerebellar Hypoplasia=====
 
=====Skeletal Malformations=====
 
=====Skin Defects=====
 
=====Muscular Defects=====
 
=====Cardiac Defects=====
 
=====Sexual Organ Malformation=====
 
=====Metabolic Diseases=====
 
 
 
===Growth Disorders During Life===
 
====Atrophy====
 
====Hypertrophy====
 
====Hypoplasia====
 
====Hyperplasia====
 
====Metaplasia====
 
====Dysplasia====
 
====Anaplasia====
 
====Neoplasia====
 
=====Benign Tumours=====
 
=====Malignant Tumours=====
 
=====Aetiology of Tumours=====
 
=====Phases of Tumour Growth=====
 
=====Tumour Classification and Nomenclature=====
 

Latest revision as of 12:42, 15 February 2011