Chronic cell injury and adaptations Flashcards
If the injury is sublethal and chronic the cells may:
- adapt
- accumulate normal or abnormal substances
What is autophagy?
- self eating
- survival mechanism
- consume damaged organelles
- consume own proteins and carbs as a source of nutrition
- protects cell from death
- limits inflammation if cell dies
What is heterophagy?
- where a cell phagocytosis another cell or part of another cell
What epithelium is this showing?
- normal ep
- simple columnar of mammary gland
- purple shows nuclei
What is shown here?
- atrophy = decrease in tissue mass due to decreased size and/ or number of cells after it has reached normal size
What are the causes of atrophy?
- nutrient deprivation
- loss of hormonal stimulation
- decreased workload
- loss of innervation
- compression
What is hypoplasia?
- tissues decreased in size because they never developed completely
What is this showing?
- Hypertrophy = increase in tissue mass due to increased size of cells (parenchymal cells, not stroma or leukocytes)
- increased size and number of organelles within cells (not water)
Causes of hypertrophy?
- increased workload
- increased hormonal stimulation
What is this showing?
- Hyperplasia = increase tissue mass due to increased number of cells
- subsides if stimulus removed
Causes of hyperplasia?
- increased workload
- increased hormonal stimulation
- inflammation
- physical trauma
(can be precursor to neoplastic transformation)
What is this showing?
- Metaplasia = change from 1 differentiated cell type to another
- e.g. squamous metaplasia (replacement of glandular with stratified squamous ep)
- can be seen in healing after mastitis
Purpose of metaplasia?
- protective mechanism
- can have negative consequences
What is this showing?
- Dysplasia = abnormality in formation of a tissue
- in ep it implies:
- increase in number of poorly differentiated cells
- disorganised arrangment
- variable appearance
- can be precursor to neoplasia
Why do injured cells accumulate exogenous and endogenous substances?
- altered metabolism
- genetic mutations
- exposure to indigestable exogenous substances
What is Lipidosis?
- accumulation of lipid within parenchymal cells e..g. hepatocytes
Causes of lipidosis?
- increased fatty acid metabolism
- abnormal cell metabolism
- impaired release of lipoproteins
What is the appearance of lipidosis?
- swollen, yellowed liver
- greasy texture
- may float in water
What is the micro appearance of lipidosis?
- sharply defined large lipid vacuoles
- distend the cytoplasm
- displace the nucleus peripherally
- can see spaces where fat would be (washes out)
Where is glycogen normally stored?
- hepatocytes
- skeletal muscle cells
In what situations is glycogen depleted?
- starvation
- sick animals
When does glycogen accumulated intracellularly?
- excessive in glycogen storage disease
- in the liver with diabetes mellitus and canine hyperadrenocorticism
What is the gross appearance of glycogen hepatopathy?
- mottled
- brown
- swollen liver
- if cut with a knife would not be greasy - not lipidosis
What is the micro appearance of glycogen hepatopathy?
- poorly defined
- small
- irreguarly shaped vacuoles (feathery)
What colour does protein stain with H&E?
- pink
What colour do nucleic acid stain?
- blue
What would you observe with the accumulation of protein in cells?
- Hylaine = glassy appearance
When can protein accumulation be normal?
- Russell bodies of plasma cells
What is this showing?
- kidney
- purple is nucleus
- pink is cytoplasm
- granular and dark pink cytoplasm = protein that shouldnt be there
What are viral inclusion bodies?
- feature of some viruses
- can be intranuclear, intracytoplasmic or both
- can be eosinophilic, basophilic or amphophilic
What is this showing?
- virus (pink blobs in the nucleus and cytoplasm)
Name the examples of extracellular accumulations
- hyaline (protein) substances
- pathological calcification
What is this showing?
- hyaline substance accumulation (extracellular)
- stain homogenously eosinophilic on H&E stains
- not indicative of a single protein
- (kidney)
What is this showing?
- hyaline protein accumulation in kidney
- protein casts in the lumen of renal tubules (albumin, haemoglobin, myoglobin)
- serum or plasma in blood vessels
- serum proteins in vessel walls
- collagen fibres in some scare
- collegaen encusted with proteins from eosinophils
- thickened basement membranes
- fibrin thrombi
- amyloid
What is this showing?
- Pathological calcification
- deposition of calcium salts in soft tissues
What is Metastatic calcification?
- calcification of soft tissues due to elevated serum calcium e.g.
- renal failure
- PTHrp in some neoplasms
- bone invasion and lysis in some neoplasms
- Vit D toxicity
What is dystrophic calcification?
- calcification of dead tissue (soft tissue necrosis)
- body is trying to make the tissue more inert
- calcium does not react with anything
What is Calcinosis cutis?
- calcification of the ep and collagen of the skin
- canine hyperglucocortioidism (Cushings)
What is Calcinosis circumscripta?
- localised calcification of the dermis or subcutis
- tends to happen on pressure points/ often bony prominences
- a form of dystrophic calcification
Name the exogenous pigmented substances
- carbon and dust
- anthracosis (black carbon pigment)
- pneumoconiosis (lung disease due to dust)
- tattoos
- pigmentation of lymph nodes
- carotenoid pigments
- yellow colouration to plasam and lipid laden cells
- tetracycline
- yellow to brown discolouration of teeth if present during tooth development + bone
What are the nonhaematogenous pigments?
- melanin
- lipofuscin
- ceroid
What is this showing?
- Melanosis = localised deposits of melanin (not a lesion)
What does copper deficiency cause?
- fading coat colour (copper required in production of melanin)
What is vitiligo?
- autoimmune attack of melanocytes
What is lipofuscin?
- yellow-brown lipoprotein that accumulates as residual bodies in secondary lysosomes
What is ceroid?
= lipofuscin-like but accumulates in disease states (particularly oxidative stress)
What are the haematogenous pigments?
- haemoglobin
- haematin
- haemosiderin
- haematoidin
- bilirubin
- porhyria
