Gross pathology and the basis of disease Flashcards
What criteria should be used to describe lesions?
location
number/extent
demarcation
distribution
colour
size
shape
consistency and texture
Describe this lesion
On the 1.forelimb, there was a clipped area measuring 10 x 5 cm. Within the clipped area is 2. a 3.well-demarcated, 4. focal, 5. pink to dark red, 6. 3 cm in diameter x 2 cm height 7. round, raised, 8. firm, hairless mass.
Describe this lesion
The 1. stomach was 4. diffusely distended, 8. gas-filled and 5. diffusely dark red.
Describe this lesion
Affecting 20% of the right kidney, within the renal cortex and extending into the medulla, was a focal, well-demarcated, 3 x 2 cm, light tan to dark red, wedge-shaped lesion.
Describe this lesion
Affecting 30% of the tongue, on the left underside and extending to the lingual surface, there was a focal, moderately well demarcated, pink to red, 5 x 2 x 1 cm, oval, multinodular, firm mass
Describe this lesion
Focally extensively, effacing the perineum and base of the tail, was a well-demarcated, black to red, approximately 1 meter by 50 cm x 10 cm, ulcerated, multinodular mass.
Describe this lesion
Adhered to the viscera and mesentery of the ileum and paired caeca, were numerous, well demarcated, multifocal, up to 2 cm in diameter, pink to tan, round firm masses.
Describe this lesion
Affecting up to 90% of the mammary gland, there was multifocal to coalescing, poorly demarcated areas of grey to light pink, friable tissue, admixed with haemorrhage and abundant light pink purulent exudate (pus).
What are possible causes of cell injury?
Oxygen deprivation
Physical agents
Chemical agents and drugs
Infectious agents
Immunologic reactions
Genetic derangements
Nutritional imbalances
What are the possible reasons for oxygen deprivation (hypoxia) causing cell injury?
Reduced blood flow (= ischaemia)
Inadequate oxygenation of the blood (cardiorespiratory failure)
Decreased oxygen-carrying capacity of the blood (anaemia, carbon monoxide poisoning, blood loss)
Give examples of physical agents that can cause cell injury
mechanical trauma
extreme temps
radiation
electric shock
Give examples of chemical agents and drugs that can cause cell injury
Hypertonic concentrations
Poisons
Environmental pollutants
Insecticides, herbicides
therapeutic drugs
Give examples of infectious agents that can cause call injury
viruses (& prions)
Bacteria
Fungi
Parasites (protozoa, helminths)
What is reversible degeneration?
Early response to cell injury
Depletion of cellular energy stores (ATP):
- cellular swelling/fatty change
- alteration of intracellular organelles
- affects functionality of cell
Why do cells swell after injury?
What causes fatty change in an injured cell?
Describe the features of necrosis after cell injury
- Always pathologic
- Cell membranes are damaged
- Often with inflammation (neutrophils attack the leaked cell contents)
Describe the features of apoptosis after cell injury
- may be physiologic or pathologic
- Cell membranes are intact
- No inflammation
- ‘Cell suicide’ or ‘programmed death’
- Cell shrinks
Describe the cytoplasmic changes that occur in necrosis?
Hypereosinophilia
Cytoplasmic vacuolation
Describe the nuclear changes seen in necrosis
Label the histological signs of necrosis
Give examples of the patterns of tissue necrosis
Coagulative necrosis
Liquefactive necrosis
Gangrenous necrosis
Caseous necrosis
Fat necrosis
Describe coagulative necrosis
Localized area of coagulative necrosis caused by ischaemia due to vascular obstruction
Describe liquefactive necrosis
Collection of necrotic neutrophils and tissue debris
describe gangrenous necrosis
Variant of coagulative necrosis
Usually applied to a limb that has lost its blood supply(also tail, ears, udder)
3 types of gangrene: dry, moist or gas
Describe caseous necrosis
Conversion of dead cells into a friable mass (resembles cheese)
More chronic than coagulation necrosis
Describe fat necrosis
Focal areas of fat destruction
Fat appears while, firm, chalky, resembling flecks of soap
Caused by release of pancreatic lipases
What are the microscopic morphological alterations seen in apoptosis?
Cell shrinkage
Chromatin condensation
Cytoplasmic blebs and apoptotic bodies
Phagocytosis of apoptotic cells or cell bodies
What are the types of cell/tissue adaptation and what causes them?
Describe the ability of labile cells to adapt
Routinely proliferate:
→ epidermis, intestinal epithelium, bone marrow cells
- hyperplasia more likely
Describe the ability of stable cells to adapt
Intermediate in ability to regenerate/divide
→ bone, cartilage, smooth muscle
- hypertrophy more likely
Describe the ability of permanent cells to adapt
Very little capacity to regenerate
→ neurons, cardiac/skeletal muscle cells
- can undergo hypertrophy
What is the stimulus of hypertrophy and hyperplasia?
Increased functional demand (e.g. muscle)
stimulation by hormones (e.g. uterus during pregnancy)
growth factors (or even some viruses)
Give an example of physiologic atrophy
e.g. during embryonal/fetal development, uterus atrophy after parturition
What are the possible causes of pathologic atrophy?
Decreased workload (atrophy of disuse)
Loss of innervation (denervation atrophy)
Diminished blood supply
Inadequate nutrition
Loss of endocrine stimulation
Pressure
What are the possible causes of metaplasia?
Chronic irritation
Deficiencies e.g. Vit A
Result of cell/tissue injury
Oestrogen toxicity
What is metaplasia?
Potentially reversible change in which one differentiated cell type (epithelial or mesenchymal) is replaced by another cell type
What is the most common metaplasia?
columnar to squamous epithelial
Define agenesis
never developed
Define aplasia
started development but stopped early
Define atresia
absence of an orifice
Define hypoplasia
incomplete development
Define dysplasia
disordered growth
