Lecture 2: Tissue Responses to Injury and Adaptations Flashcards
What are labile cells
Continuously cycling cells that proliferate at high rate, high regenerative capacity
What are some examples of labile cells
Epithelia of the mouth, skin , gut, bladder, and bone marrow cells
What are quiescent tissue
Stable cells, divide infrequently but can be stimulated to divide when the cells are lost. In Go until stimulated to G1
What are some examples of quiescent tissues
Liver, renal tubular cells, fibroblasts, endothelial cells, smooth muscle cells, chondrocytes, osteocytes
What are permanent cells
Non-dividing tissue that divide in embryonic and fetal life then leave cell cycle. Cells can’t be replaced when lost and have limited capacity to divide
What are some examples of permanent cells
Neurons, cardiac, photoreceptors
Is the following: normal, atrophy, hypertrophy, or hyperplasia
normal
Is the following: normal, atrophy, hypertrophy, or hyperplasia
Hyperplasia
Is the following: normal, atrophy, hypertrophy, or hyperplasia
hypertrophy
Is the following: normal, atrophy, hypertrophy, or hyperplasia
Atrophy
The left picture is normal, what tissue change is noted in right image (note: image at same magnification
Atrophy
What is the mechanism of cell loss in the following atrophies: thymus involution, uterine involution after pregnancy, mammary glands following lactation, testicular atrophy in old age
Apoptosis- programmed cell death not pathological
What is the pathogensis of hydronephrosis
- Blockage in urinary bladder (ex: transitional cell carcinoma)
- Block ureter outflow
- Increase pressure on renal pelvis
- Renal and cortical medically atrophy
- Hydronephrosis
What are some reasons for pathological hyperplasia and hypertrophy
- Abnormal increase in functional demand
- Excessive hormonal stimulation
- Reactive-response to inflammation or chronic trauma
Which image is normal and which abnormal, what is wrong with abnormal image
Left: normal epidermis
Right: epidermal hyperplasia
What tissue is this? Which is normal vs abnormal? What is abnormality
Cardiomyocytes
Left: hypertrophic cardiomyopathy
Right: normal
Is the following erosion and ulceration and how do you know
erosion because basement membrane is intact
In terms of regeneration, what is the capacity of epithelium to response to injury
High regeneration capacity due to epithelial cells being labial cells that are continuously going through cell cycle
Is this ulceration or erosion and how do you know
ulceration- damage the basement membrane
Ulceration can lead to severe/acute or chronic ___ and perforated ___
Hemorrhage, perforated ulcer
Does regeneration occur in ulceration injuries?
No, damage basement membrane with stem cells, resolution through scaring/fibrosis
Identify which image shows erosion vs ulceration
Left: erosion
Right: ulceration
What is the most common cause of stricture in the esophagus
Circumferential erosion or ulceration by pressure necrosis
What is the worst outcome of ulceration in the stomach
Perforation leading to peritonitis
This image shows an esophagus, what is wrong
ulcerated
This image shows a stomach what is wrong
ulcerated
Can the liver regenerate after an acute injury
Yes, quiescent cells can regenerate
Can liver regenerate after repeated injury
No fibrosis will occur—> leading to modular regeneration/cirrhosis of the liver
Identify the pathologies of the liver
top left: normal
Bottom left: cirrhosis
Top right: lipidosis
What do both of these stains of the liver show
Cirrhosis—> increase in fibrosis connective tissue
What stain stains the fibrous CT blue to identify cirrhosis of the liver
Trichrome stain
How does the heart and skeletal muscle respond to reversible injury
Atrophy and hypertrophy
How does the heart respond to irreversible injury? What is its regenerative capacity
Cardiomyocytes are permanent cells and therefore can’t regenerate—> outcome is fibrosis/scaring
What is concentric hypertrophy
Thickening of the outside of the heart towards the lumen, add sarcomeres on top
What is eccentric hypertrophy
Caused by addition of sacromeres to the side of the heart allowing for enlargement and dilation
Identify the tissue type? Identify normal vs abnormal? What is causing abnormality?
Cardiomyocytes
Left: normal
Right: abnormal- myocardial fibrosis
What are the key forms of neurological injury
- Compression
- Necrosis
- Degeneration
How does the brain respond to injury and heal
Minimal regeneration of nerve fibers or neurons, but does not heal via fibrosis but damage leaves cavitation
Does the brain heal by fibrosis
No, damage results in cavitation
What is anthracosis
Exogenous black pigment found in lungs as a result of air pollutants
What does the following image of the lung show
anthracosis
How is melanin formed
Oxidation of tyrosine
What is the endogenous pigment lipofuscin
“Wear and tear” pigment, age indicator
What does the endogenous pigment ceroid show
Pathogenic indicator, associated with vitamin E deficiency
Both images show melanin pigmentation, which is benign and which is malignant
left: benign- look more like discoloration marks rather than masses
Right: more like black masses
What do both these histologies show? What is the difference between them and how do you know
both show melanin
Left: malignant melanoma- can tell due to high cellular atypica
Right: pigment are incontinence- benign reaction to inflammation
Describe the mechanism in which cooper deficiency causes a fading in coat color of sheep and cattle
Melanin is formed by oxidation of tyrosine which requires a copper containing enzyme tyrosinase, therefore copper deficiency—> decreased melanin
What causes jaundice coloration
Presence of bilirubin
What causes hematin (brown) coloration
- Artifact of Formica acid and heme
- Liver flukes
How would you describe this pigmentation
jaundice- excess bilirubin as a result of liver tumor
How would you describe this pigmentation
Hematin
What is the mechanism that normally makes us avoid gout
Blood uric acid uses enzyme Uricase to form Allantoin which is then excreted in urine
How does gout occur
Increase in blood uric acid due to lack of uricase enzyme so not converted to allantoin
What does the following image show
gout crystals
What is the most common form of amyloid/amyloidosis in animals
Reactive secondary to inflammation- amyloid A deposits accumulate as acute phase proteins produced during inflammation
Where are amyloid deposits commonly found
Kidney, liver, spleen, and lymph nodes
Which image is normal? What is abnormality?
left: normal
Right: abnormal: amyloidosis
What is wrong here and what stain was used
amyloidosis identified with Congo red stain
What is wrong here and what stain was used
amyloidosis identified with congo red stain that turned apple green under polarized light
What is the difference between dystrophic calcification and metastatic calcification
- Dystrophic calcification: localized increase in calcium, blood calcium levels are normal
- Metastatic calcification: blood Ca2+ levels are increased-> hypercalcemia
In general what is indicated by the arrows in both pictures
viral inclusions
What staining technique do you want to use to identify viral inclusion bodies in lead poisoning and what tissue are they found in.
Acid fast
Tissue: renal tubules
what is shown here? Blood ca2+ is normal
Dystrophic calcification
What is shown here? Patient was hyperglycemic
metastatic calcification
