|
|
| (43 intermediate revisions by 5 users not shown) |
| Line 1: |
Line 1: |
| − | ==An Introduction to General Pathology==
| + | #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 [[General Pathology - Post-Mortem Change|changes]] are encountered at post-mortem examination.
| |
| − | *# Those due to the '''disease'''
| |
| − | *#* Lesions
| |
| − | *# Those occuring '''immediately prior to death'''
| |
| − | *#* [[General Pathology - Post-Mortem Change#Agonal Changes|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 Mineralisation]]===
| |
| − | | |
| − | ===[[General Pathology - Circulatory Disorders|Circulatory Disorders]]===
| |
| − | | |
| − | ===[[General Pathology - Inflammation|Inflammation]]===
| |
| − | | |
| − | ===[[General Pathology - Disorders of Cell Growth|Disorders of Cell Growth]]===
| |
| − | | |
| − | ===[[General Pathology - Congenital and Neonatal Disease]]===
| |
| − | | |
| − | | |
| − | | |
| − | | |
| − | | |
| − | ==Congenital and neonatal disease==
| |
| − | | |
| − | ===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=====
| |