VNSA13 Flashcards
(17 cards)
What is pathology?
Branch of medical science that involves the study of the causes of diseases, how they develop and their effect on the body.
General pathology - study of processes in the disease, without limiting discussion to a particular tissue or organ. Inflammation and neoplasia are examples of this.
Systemic pathology - the study of general pathology processes with special reference to specific tissues or body systems. Dermatitis and osteosarcoma are examples of this.
Define aetiology
The cause of a disease.
Define pathogenesis of a disease
Describes the development process of a disease, how certain factors lead to the disease, or the mechanism of disease development.
Describes the chain of events from the initial stimulus to the manifestation of the disease or the lesion produced.
Cell changes
Can either be;
Reversible - can recover when harmless stimulus stops. Can involve accumulation of endogenous or exogenous substances within the cell.
Irreversible - cell dies or cannot return to normal function
Define coagulative necrosis
The most common. Found in solid organs (eg kidneys)
Retain structure but are pale after a period of time, inflammatory cells start to remove damaged or dead cells so gradual change in appearance.
Proteins are released by dying cells (diagnostic values)
Creatine kinase = muscle damage
Alanine aminotransferase = liver damage
Define liquefactive necrosis
Aka as colliquaitve necrosis.
Areas of necrosis become liquified by powerful enzymes
Characteristic to the brain - occurs after interruption to the blood supply or bacterial infection (meningitis)
Define caseation necrosis
Converted to a cheesy texture.
Associated with chronic bacterial infection (tuberculosis)
Due to the presence of special fats in the bacterial wall which prevent liquidefaction.
Define fat necrosis
After inflammation in/around fatty tissue.
Caused by enzymes that degrade fat cells so fat becomes hard and nodular.
(Pancreatitis, trauma; in horses with badly fitted harnesses)
Define gangrene
Types if coagulation necrosis due to loss of blood supply to area, especially extremities.
Bacteria are usually involved; contaminated wounds.
Name the type of gangrene
Dry - no bacteria, tissue goes cold, shrivelled and discoloured.
Gas - gas producing bacteria, tissue has a crackly feel (crepitus)
Moist - pus producing bacteria, tissue rotten and foul smelling
Wet - bacteria present with inflammation of adjacent non-necrotic tissue. Swells and oozes fluid.
What is sequelae of necrosis ?
After effect of a disease
Tissue regeneration, scar formation, erosion or ulceration and sequestration
Extracellular changes
(RE pathology)
Mineralisation - calcification in normal or abnormal tissue.
Dystrophic calcification; Ca2+ deposited locally where tissue is damaged
Metastatic calcification; when persistent high Ca2+ levels, vit D toxicity, excess parathyroid hormone, kidney failure.
Dental plaque - hard crust on gums due to gum inflammation, bacteria and saliva.
Kidney, bladder or bile stones (calculi)
Crystals - certain substances from crystalline materials. (Liquid antifreeze and calcium oxalate crystals in kidney). Rates or uric acid: gout. Normally acidic with allantoin in liver equals urea.
Protein - amyloid is an abnormal form of protein that can accumulate in certain chronic infectious, inflammatory, immune, metabolic or neoplastic diseases. Can also be an aging change.
Name aetiological agents (internal + external)
Internal - genetic, immune system, ageing
External - physical, chemical, infectious, environmental (nutrition, temp, hygiene, radiation)
Define acute and chronic
(Disease classification)
Acute - Conditions or symptoms that have a sudden onset and are typically of short duration.
Chronic - persisting for a long time or constantly recurring.
Define acquired and congenital
(Disease classification)
Acquired - developed or originating after birth
Congenital - a condition/trait present at birth
Define hereditary and idiopathic
(Disease classification)
Hereditary - trait/disease/condition passed from parents to offspring through genes. Not necessarily present at birth.
Idiopathic - disease/condition passed on where the cause is unknown.
Define simple and multifactorial
(Disease classification)
Simple - an aetiological agent affecting a cell/tissue/organ
Multifactoral - affected by lots of other factors and infectious agents.
