pathology (wk 1) Flashcards
what does aetiology mean?
the cause of the disease - greek
what does pathogenesis mean?
the mechanism (sequence of events resulting in) the disease - from greek word for generation of suffering
what are gross lesions?
structural abnormalities that are visible to the naked eye
what are pathognomonic lesions?
lesions so distinctive they can only have one possible cause
what are histological lesions?
structural and/or architectural changes that are only detectable under the microscope
what is a biopsy?
removing a sample of tissue (surgically or post mortem) for analyzation
what is a cytology?
similar to a biopsy, but studying cells that have been smeared and blotted onto a microscope slide before examination - not the tissue as a whole
what is the cause/aetiology of goitre (enlargement of the thyroid gland)?
a. Neoplastic transformation of epithelial cells
a. Bacterial invasion and proliferation
c. Protein deficiency
d. Iodine deficiency
d. Iodine deficiency
what is algor mortis?
the cooling of the body after death
what is the stiffening of muscles after death called?
rigor mortis
why does rigor mortis occur?
once ATP runs out (uncoupling of actin-myosin complexes in muscle is an energy-requiring process) muscles can no longer relax, and sustained contraction of fibres begins to occur
post mortem changes - what is hypostatic congestion (lividity or livor mortis)
colour change associated with the gravitational pooling of blood
post mortem clots vs ante mortem clots (thrombi) - which is which?
1. conforms to the vessel shape, is smooth and glistening with a pale clot of serum
2. rough and granular, don’t seperate into red and white layers, and are often attached to the blood vessel wall
- post mortem clot - (conforms to the vessel shape, is smooth and glistening with a pale clot of serum)
- thrombi - (form in a living body, rough and granular, don’t seperate into red and white layers, and are often attached to the blood vessel wall)
what is autolysis?
the breakdown of cells and tissues by the body’s own cellular enzymes
what is putrefaction?
breakdown of cells and tissues by bacteria that invade from the environment or from within the body (eg gut flora)
true or false - neonatal animals are slower to putrefy
true - they have not acquired an intestinal flora
Post-mortem degeneration (decay) of a body and its organs involves two processes that differ in origin but occur simultaneously - what are they?
autolysis and putrefaction
Autolysis results in breakdown of tissue fibres and cells, causing loss of colour and tissue fragility (friability). In some organs this can mimic disease processes (e.g., fatty liver – see later). what is this called?
paleness and friability (original, I know)
what is pseudonecrosis?
areas of discolouration (often paleness) and softening within organs that mimics the appearance of groups of dead (necrotic) cells - but without the telltale ring of inflammation that should be present with necrosis in a live animal
what is pseudomelanosis?
dark staining of the tissues (greenish black) caused by production of iron sulphide made from interactions between invading anaerobic bacteria (brings hydrogen sulphide) and red blood cells (iron)
what is haemoglobin imbibition/staining?
haemoglobin from inside the cell comes outside of the cell due to cell breakdown, starts colouring the tissues around it. Takes longer than hypostatic congestion, with a more diffused change of colour. Affects all of the organ.
what is bile imbibition/staining?
yellowish - similar to haemoglobin inhibition, but occurs around the gall bladder. When the cells of the gall bladder die, the bile escapes and stains nearby cells
what is gas production/bloat caused by?
anaerobic putrefactive bacteria produce gas, that then accumulates in body cavities
1a. Photograph of a piglet found dead in its shelter. SELECT the post-mortem change present.
1. Algor mortis
2. Putrefaction
3. Bile imbibition
4. Hypostatic congestion
- Hypostatic congestion - this is the red streaks. the white streaks are due to the boarded floor.
this piglet has hypostatic congestion - which side was it found dead on?
1. left lateral recumbency
2. right lateral recumbency
- left lateral recumbency
Intestinal loops from a dog that have been dead for > 24hs with no refrigeration. SELECT the post-mortem change shown on the image.
1. Haemoglobin staining
2. Thrombosis
3. Rigor mortis
4. Lens opacity
- Haemoglobin staining
Lungs from a 2-year-old dog. select the post-mortem change present in this case.
1. Haemoglobin imbibition
2. Hypostatic congestion
3. Rigor mortis
- Hypostatic congestion - there is gravitational pooling of blood on the right lung lobe
Liver and gallbladder from a cat. Can you tell what post-mortem change is present in the area indicated by the arrows?
1. Hypostatic congestion
2. Post mortem clot
3. Bile imbibition
4. Lens opacity
- Bile imbibition - see yellow discolouration
Photograph showing the skin of the abdominal wall of a dead dog. What is the post-mortem change seen in the skin?
1. Mucosal sloughing of the rumen
2. Pseudomelanosis
3. Bile imbibition
4. Bloat
- Pseudomelanosis - see the blue/green discolouration of the skin
there are two post mortem colour changes present in this liver, what are they?
pseudonecrosis and pseudomelanosis
what does anoxia mean?
total lack of oxygen
what does hypoxia mean?
partial lack of oxygen
why is anoxia and hypoxia bad for a cell?
Both can affect the
- cell membrane (leading to damage of the lipid bilayer and dysfunction of the sodium-potassium pump) and
- enzymatic system (leading to decreased ATP production and dysfunction of the sodium-potassium pump).
ATP is produced mainly in what organelle?
1. Mitochondria
2. Lysosome
3. Nucleus
4. RER
- Mitochondria - generation of ATP is it’s main role
SELECT the main mechanism for production of ATP:
1. Oxidative phosphorylation of ADP
2. Pentose phosphate pathway
3. Fatty acid oxidation
4. Glycolytic pathway
- Oxidative phosphorylation of ADP
What do you think will happen to the intracellular space when the sodium-potassium pump is damaged or not working - what is the net movement of ions?
the normal net movement is outside the cell - for each ATP made, three Na+ ions go outside the cell and two K+ to inside. without it, the cell will swell
why do cells swell (hydropic degeneration) without a functioning Na+/K+ -ATPase pump?
Na+ moves into the cell down it’s concentration gradient, and water follows
cell swelling can be reversible as long as the damage is mild/of short duration - at what point does it become irreversible?
when mitochondria are damaged and membranes rupture
what are the two forms of cell death?
- apoptosis (cell degeneration)
- necrosis
what is apoptosis?
a form of cell death that does not trigger an inflammatory process (eg the shrinking of a tadpole’s tail) , usually a single cell or just a few cells are affected. the cells shrink, and organelles and nuclear fragments are extruded as membrane bound structures called apoptotic bodies
what is necrosis?
a form of cell death that results from irreversible cell damage - the influx of calcium through the damaged cell membrane is considered the point of no return
what’s the word for this nuclear change often present with necrosis: “a shrunken dark staining nucleus”
1. pyknosis
2. karyorrhexis
3. karyolysis
- pyknosis: a shrunken dark staining nucleus
what’s the word for this nuclear change often present with necrosis: “fragmentation of the nucleus”
1. pyknosis
2. karyorrhexis
3. karyolysis
- karyorrhexis - fragmentation of the nucleus
the three main microscopic appearance changes associated with necrosis?
- cytoplasmic changes (pinker than normal (eosinophilia) and shrunken
- nuclear changes (pyknosis, karyorrhexis, karyolysis etc)
- cell membrane loss
what is the word for the ‘fading’ of the nucleus as it loses affinity of haematoxylin?
1. pyknosis
2. karyorrhexis
3. karyolysis
- karyolysis
what type of necrosis is this?
coagulative necrosis (commonly seen in liver, heart, kidney and skeletal muscle) - where the architectural detail of the tissue persists, cellular detail is lost.
what kind of necrosis is commonly caused by the following - ischaemia (less blood flow than normal), hypoxia (less oxygen than normal), burns, caustic chemicals and toxic cell injury?
common causes of coagulative necrosis
what type of necrosis is this?
caseous (cheese) necrosis - where both the cellular and architectural detail are lost
what type of necrosis is this?
liquefactive necrosis - disintegration of the necrotic material into a liquid mass, in which all cellular and architectural detail is lost
what type of necrosis is most commonly seen in the central nervous sytem?
liquefactive necrosis - CNS liquefactive necrosis is known as malacia
what does liquefactive necrosis outside of the CNS form?
abscesses
what type of necrosis is particularly distributed on distal extremities of the body (eg disal limbs, teats, pinnae, tip of tail) and lower portions of certain organs (mammary glands and lung lobes?
gangrenous necrosis - of which there are three types (dry, wet and gas gangrene)
uncomplicated ischaemic (reduced blood supply) necrosis eg frostbite, where extreme vasoconstriction causes obliteration of the blood supply - is it:
1. gry gangrene
2. wet (moist) gangrene
3. gas gangrene
- gry gangrene
where ischaemiac (reduced blood supply) necrosis gets a bacterial infection, becomes dark and foul smelling - is it:
1. gry gangrene
2. wet (moist) gangrene
3. gas gangrene
- wet (moist) gangrene
bacteria caused (Clostridium spp.). these little dudes are anaerobic, usually found in the intestinal tract or on the ground. can’t grow in healthy tissue, but establish themselves in areas of necrosis or bruising where there is low oxygen content - where they produce necrotising exotoxins that diffuse into nearby healthy tissue and induce necrosis. is it…
1. gry gangrene
2. wet (moist) gangrene
3. gas gangrene
- gas gangrene - technically a special type of wet gangrene bc bacteria based. characterised by the bubbles of gas formed by the organisms being found in the gangrenous tissue (giving it a foul odour too)
what type of necrosis appears opaque, firm, white, and can cause a significant inflammatory response?
fat necrosis - the death of fat cells. there are three types (enzymatic, traumatic. and nutritional/steatitis/yellow fat disease)
fat necrosis involves the death of fat cells, a process that involves spitting stored fat into glycerol and fatty acids - the latter then combines with calcium, potassium or sodium salts to form soaps, which precipitate and look opaque compared to clear normal fat cells. what is this process called?
This process is known as saponification
occurs mainly in the adipose tissue surrounding the pancreas and is due to a release of lipase (enzyme that breaks down fats) from damaged pancreatic acinar cells - is it:
1. enzymatic fat necrosis
2. traumatic fat necrosis
3. nutritional, steatitis, or yellow fat disease
- enzymatic fat necrosis
after trauma or due to chronic pressure of the subcutaneous adipose tissue, eg a sick cow that has been in recumbency for a long time - is it:
1. enzymatic fat necrosis
2. traumatic fat necrosis
3. nutritional, steatitis, or yellow fat disease
4. idiopathic fat necrosis
- traumatic fat necrosis
secondary to diets high in polyunsaturated fatty acids and low in vitamin E (and/or other antioxidants). can be common in cats or mink on fish diets only - is it:
1. enzymatic fat necrosis
2. traumatic fat necrosis
3. nutritional, steatitis, or yellow fat disease
4. idiopathic fat necrosis
- nutritional, steatitis, or yellow fat disease
eg necrosis of abdominal fat in cows, a condition that usually occurs in over conditioned cows with an apparent predisposition in cows with Channel Island descent (Jersey, Guernsey, Dexter cows) - is it:
1. enzymatic fat necrosis
2. traumatic fat necrosis
3. nutritional, steatitis, or yellow fat disease
4. idiopathic fat necrosis
- idiopathic fat necrosis
Sequelae (outcome) of necrosis methods - how does the liquefaction and removal mechanism work?
This mechanism of dead tissue removal tends to occur when the amount of affected tissue is small, and the tissue is rich in enzymes and tissue fluid. Once liquefied, the resulting fluid and small molecules can be absorbed into the blood or lymphatics.
Sequelae (outcome) of necrosis methods - how does the encapsulation without liquefaction (sequestration) mechanism work?
occurs with “dry” necrosis, eg coagulative necrosis - dead tissue acts as an irritant, which leads to the development of new fibrous tissue and ultimately a fibrous capsule known as a sequestrum surrounding the necrotic centre
what is a sequestrum?
a fibrous capsule surrounding a necrotic centre, eg corneal sequestra (idiopathic long haired cat breed thing) and bony sequestra (post infection thing)
Sequelae (outcome) of necrosis methods - how does the abcessation mechanism work?
The formation of pus within a tissue results in an abscess. As the amount of pus increases, so does the internal pressure. This leads to pain, redness and swelling. Abscesses can resolve either by formation of a thick fibrous capsule around the pus (similar to sequestration), or by bursting, where the necrotic purulent material dissects its way out through the surrounding tissue onto the surface or lumen of the tissue involved.
is this erosion or ulceration: loss of epithelial cells only, basement membrane intact
erosion
is this erosion or ulceration - when the basement membrane is involved and underlying connective tissue is exposed?
ulceration
is regeneration and repair a post-necrosis outcome?
yes - injury to cells and tissues sets in motion a series of events to contain damage and initiate a healing process
in cases of injury or disease, cells may undergo changes to help them survive, which are referred to as…
pathological adaptations
refers to an organ or tissue that initially developed to normal size but then shrank due to a decrease in size of the individual cells making up the tissue (resulting organ has less mass). is it:
1. atrophy
2. hypertrophy
3. hyperplasia
4. metaplasia
5. dysplasia
- atrophy - can be due to less use, denervation, loss of nutrition/hormonal stimulation or compression
increase in size of a tissue or organ due to an increase in size of the individual cells (can apply to whole organ, or certain tissues within it) - is it:
1. atrophy
2. hypertrophy
3. hyperplasia
4. metaplasia
5. dysplasia
- hypertrophy - eg increased muscle size due to exercise (physiological hypertrophy), or increased ventricle wall thickness due to a narrowing valve (pathological hypertrophy)
the increase in the number of cells in a tissue or organ, which can lead to the increase in size of the organ as a whole. note - limited to cell types that can divide. is it:
1. atrophy
2. hypertrophy
3. hyperplasia
4. metaplasia
5. dysplasia
- hyperplasia - eg happens physiologically in mammary glands during lactation, or thyroid and parathryroid hyperplasia etc
where one fully differentiated cell type changes to a different but related cell type - is it:
1. atrophy
2. hypertrophy
3. hyperplasia
4. metaplasia
5. dysplasia
- metaplasia - usually involves a change to a cell type that is more durable in response to chronic irritation, for example squamous metaplasia of the bronchiolar epithelium in response to chronic irritation caused by smoking.
lack of normal histologic architecture in a tissue or organ, can be developmental (eg an abnormally shaped hip joint) or in any situation where there is a jumbled differentiation of tissue eg healing epithelium that has damaged remnants of underlying connective tissue in it - is it:
1. atrophy
2. hypertrophy
3. hyperplasia
4. metaplasia
5. dysplasia
- dysplasia
Bruno is a 2-year-old dog that fractured his left ulna 2 weeks ago and has not been putting any weight on it. What is the cellular adaptation likely occurring in the muscle cells of the affected limb?
atrophy (disuse atrophy)
Nixon was a 10-year-old Maine Coon cat with a history of sudden death. The image above shows a transversal section of the heart with increased thickness of the left (LV), right (RV) and interventricular wall (IVW) with secondary reduced size of the ventricular lumen.
What is the cellular adaptation likely occurring in the muscle cells of the heart?
hypertrophy
The image above shows Nixon’s thyroid glands. There was marked enlargement of the right thyroid gland due to increase number of thyroid epithelioid cells.
What is the cellular adaptation likely occurring in the thyroid gland?
hyperplasia (thyroid gland hyperplasia)
what is hypoplasia (a growth disturbance in-utero, not a cell adaptation)?
the incomplete growth of a tissue or organ - can vary from severe (only tiny remnants of tissue) to mild (a very slight decrease in size with relatively normal function)
(a growth disturbance in-utero, not a cell adaptation) - what is aplasia/agenesis?
the extreme form of hypoplasia (incomplete growth of tissue/organ) where there is a complete absence of the tissue - can lead to cleft palate etc
(a growth disturbance in-utero, not a cell adaptation) - what is atresia?
the term used for the absence of a lumen (the cavity within the tubular structure), eg intestinal atresia
what is ischemia?
reduced blood supply to a particular tissue or organ (Ischaen = to restrain or hold back; aemia = of blood)
is karyolysis, nuclear pyknosis, karyorrhexis, and loss of distinct cell borders:
1. necrosis
2. cell degeneration
3. cell degeneration AND necrosis
- necrosis
is cell swelling:
1. necrosis
2. cell degeneration
3. cell degeneration AND necrosis
- cell degeneration
is increased cytoplasmic eosinophilia (greater affiliated for the pink staining dye eosin than normal):
1. necrosis
2. cell degeneration
3. cell degeneration AND necrosis
- cell degeneration AND necrosis
What is the pattern of necrosis in this slide?
1. Periportal
2. Random
3. Centrilobular
- Centrilobular - most of the areas of necrosis surround a vein (the central vein)
Which of the following is associated with the increased cytoplasmic eosinophilia (increased affiliation for the pink dye eosin) that occurs in damaged and dead cells?
1. Dysfunction of sodium potassium membrane pump
2. Cross linking of cytoplasmic proteins
3. Mitochondrial dysfunction
4. Breaks in DNA strands
5. Lipid peroxidation
6. Influx of calcium
7. Loss of ribosomes
- Loss of ribosomes - ribosomes normally stain bluish (basophilic). when cells are damaged or necrotic, there is a swelling of the endoplasmic reticulum leading to a detachment and dispersal of ribosomes and without the blue staining the cells look pinker (increase on eosinophilia)
what do you think is in the damaged hepatocyte cytoplasmic vacuoles? select all that apply:
1. amyloid
2. extracellular fluid
3. fat
4. glycogen
5. ketones
6. minerals
2, 3, 4 - extracellular fluid (typical degenerating cell behaviour), fat (impaired fat metabolism), and glycogen (impaired glycogen metabolism)
necrotic tissue in which both cellular and architectural details are lost?
1. caseous necrosis
2. coagulative necrosis
- caseous necrosis - cheeseeee
necrotic tissue in which cellular detail is lost, but architectural detail is maintained?
1. caseous necrosis
2. coagulative necrosis
- coagulative necrosis
kidney from a dog - necrosis type?
coagulative necrosis
Intestine and abdominal fat from a Jersey cow. necrosis type?
fat necrosis
Lymph node from a sheep. A cytological smear from this lesion doesn’t contain any recognisable cells.necrosis type?
caseous necrosis (cheesy gland)
heart from a dog. necrosis type?
coagulative necrosis - the white areas
spinal cord from a dog - necrosis type?
liquefactive necrosis
the following histological image is from a tissue from a cow - can you recognise the tissue?
1. yes
2. no
- no - a type of caseous necrosis, so both the cell structure and more importantly tissue architecture is lost - there’s no clues as to the origin of the tissue
Hardy, a 12-year-old entire male huntaway has been constipated for a week. On a digital rectal examination Hardy’s caudal rectal lumen is narrowed by a smooth symmetrical bi-lobed structure which pushes the rectum up from below. what is this structure most likely?
1. Fracture callus on pelvic floor
2. Intestinal foreign body
3. Enlarged kidney
4. Prostate gland
5. Urethral tumour
6. Renal tumour
7 Bladder
- Prostate gland
which of the following processes usually result in enlargement of an organ or tissue?
1. agenesis
2. aplasia
3. atrophy
4. dysplasia
5. hypertrophy
6. hyperplasia
- hypertrophy, and 6. hyperplasia - an enlarged organ could either by hyperplastic, hypertrophic, or both
which box is aplasia?
b - aplasia = the absence of a tissue or organ; an extreme form of hypoplasia
which box is atrophy?
a - atrophy = an organ or tissue that is smaller than normal due to a decrease in size of individual cells. atrophic organs are those that initially reached normal size, but then decreased due to some pathological process
which box is hyperplasia?
e - hyperplasia = an increase in size of a tissue or organ due to an increase in size of cell NUMBERS
which box is hypertrophy?
c - hypertrophy = an increase in size of an organ or tissue due to an increase in individual cell SIZE
which box is hypoplasia?
d - hypoplasia = incomplete growth of an organ or tissue; hypoplastic organs never reach full size (different to atrophy, which reached full size then shrank)
histological images of normal (left) and enlarged prostate (right) - is this prostate:
1. hypertrophic
2. hyperplastic
- hyperplastic - the prostate responds to testosterone secretion with proliferation (rapid increase in amount) of epithelial cells
hardy, the constipated enlarged prostate dog, needs to be castrated to remove the source of testosterone and prevent the hyperplasia recurring - what term would best describe the change in hardy’s prostate after castration?
1. Atrophy
2. Aplasia
3. Atresia
4. Dysplasia
5. Dystrophy
6. Hypertrophy
7. Hyperplasia
8. Metaplasia
- Atrophy - it grew, and then shrank again
What type of epithelium are the prostatic ducts from the dog with the testicular tumour lined by?
1. Columnar
2. Cuboidal
3. Squamous
4. Transitional
- Squamous epithelium cells
