Intro to pathology Flashcards
What is the difference between general and systemic pathology?
General: study of basic responses of cells/ tissues to insults and injuries irrespective of the organ involved.
Systemic: study of alterations in specialised organs and tissues that are responsible for disorders that involve these organs
What is anatomic pathology?
Examination of tissues taken during life (biopsy) or after death (necropsy). Examines the nature/ extent of the disease.
What is clinical pathology?
Examination of blood (and other bodily tissues) as well as cytology during life.
What are the 4 aspects of disease?
1) Aetiology: cause of disease
2) Pathogenesis: mechanisms of disease development
3) Molecular and morphologic changes: biochemical/ structural alterations induced in cells and organs
4) Clinical manifestation: functional consequences of molecular and morphologic changes
Discuss the internal/ external causes of disease
Internal: aging/ immunologic defects/ genetic defects
External:
Agents- physical/ chemical/ biological
Deficiencies- nutritional/ external
What is meant by molecular changes?
Biochemical alterations in tissues/ cells (morphologic means the structural changes)
What are the major processes of pathology?
- inflammation
- healing
- thrombosis
- neoplasia
- metabolic dysfunction
- necrosis
What is the definition of inflammation?
Vascular response of the tissues and interstitium. Designed to SEQUESTER, DILUTE and DESTROY the causal agent
What is the definition of neoplasia? (very briefly)
-Very simply it is a mass of uncontrolled cells
What is meant by metabolic dysfunction?
Abnormalities/ imbalances of carbohydrate, fat and protein metabolism in the cell. Leads to accumulation of glycogen/ fat/ proteins.
What is the definition of ‘diagnosis’?
Conclusion concerning the NATURE, CAUSE or NAME of a disease.
(accuracy of diagnosis is limited by evidence of lesions available for study)
What are the types of diagnosis?
- Clinical
- Clinical pathologic
- Morphologic
- Aetiologic
- Disease
What are the methods used to reach a diagnosis?
- Morphology
- Molecular biology
- Microbiology
- Immunology
- Genetics
Describe Macroscopic examination of morphologic changes
- Observed by unaided eye
- Deviations in size/ colour/ texture/ location from normal organs and tissues
Describe microscopic examination of morphologic changes
-Light microscopy: histopathology (often using stains)
-Electron microscopy: transmission EM (2D- shows internal cell structure)
Scanning EM (3D- resticted to cell surface)
What are the molecular method involved in reaching a diagnosis?
- PCR
- Genomics (DNA sequencing)
- Proteomics
- Immunological approaches
What is PM autolysis?
Self digestion after death
What is the definition of putrefaction?
Colour/ texture changes/ gas production and odours caused by PM bacterial metabolism and dissolution of host tissues. (remember mainly bacterial)
List the changes that occur after death
- Rigor mortis
- Algor mortis
- Livor mortis (hypostatic congestion)
- PM clotting
- Pseudomelanosis
- Bloating
- Softening
- Lens opacity
What causes rigor mortis?
Depletion of ATP and glycogen - the cross links formed from contracting muscles cannot be broken.
It is dependant on the temperature of both the animal and the environment
What is algor mortis?
Gradual cooling of the liver
What is liver mortis?
Gravitational pooling of blood down on side of the animal, the patterns visible can be used to help determine the position of the animal at death. Normal process.
What is PM clotting?
Occurs in the heart and BV. Within several hours of death.
What is haemoglobin imbibition and bile imbibition
- Haemoglobin: red staining of tissue, the integrity of BV walls is lost to haemoglobin is released
- Bile: bile from the gallbladder penetrated wall and stains adjacent tissue yellow/ brown
What is pseudomelanosis?
-Blue green discolouration of the tissue by iron sulphide (FeS).
It is involved with putrefaction NOT autolysis.
What causes PM bloating?
-Result of PM bacterial gas formation in the lumen of the GI tract
What causes PM softening?
softening of tissue results from autolysis of cells and CT often aided by putrefactive bacteria
What causes PM lens opacity?
Occurs when the carcass is very cold or frozen. Often reverses as body warms.
