Cell Injury, Adaptations, and Death Flashcards
1
Q
- A 50-year-old male dies during a car accident. At autopsy, he is noted to have a moderately stenotic
aortic valve. The heart weighs 500 grams. The cause
of death from the motor vehicle accident is entirely
blunt force injuries of the head and neck, including an
atlanto-occipital dislocation. No internal injuries below
the neck are identified. There is no history of heart failure.
A section of the myocardium from the left ventricle
would reveal which of the following processes?
A. Hypertrophy
B. Hyperplasia
C. Atrophy
D. Metaplasia
E. Reversible cell injury
F. Irreversible cell injury
A
- Correct: Hypertrophy (A)
Because of the stenotic aortic valve, increased pressure
is placed on the left ventricular myocardium, which
responds by increasing the size of the cells, which
is hypertrophy (A). The myocardium has adapted
to the increased pressure, and since then there has
been no heart failure and no reversible or irreversible
cell injury (E, F). Cardiac myocytes are essentially
not capable of division and are increasing in size,
not decreasing, so neither hyperplasia nor atrophy is
occurring (B, C), and there is no switch in type of cell
(e.g., cardiac muscle to another form of mesenchymal
tissue), so metaplasia is not occurring (D).
2
Q
- A 25-year-old male, who is an offensive lineman
for the local college football team, dies during a car accident.
At autopsy, the injuries, being multiple rib fractures
and lacerations of the lungs and heart, with 1500
mL of blood found in the left pleural cavity, are confined
to the chest. At autopsy, a biopsy of his left biceps femoris
muscle would reveal which of the following?
A. Physiologic hyperplasia
B. Pathologic hyperplasia
C. Physiologic hypertrophy
D. Pathologic hypertrophy
E. Physiologic atrophy
F. Pathologic atrophy
A
- Correct: Physiologic hypertrophy (C)
As the decedent is athletic, there is a stimulus causing
enlargement of the biceps femoris muscle, and
as athletic activity is a normal activity, the resultant
enlargement of the skeletal muscle cells would
be considered physiologic and not pathologic. The
skeletal muscle cells cannot divide, so they would
respond to increased workload by increasing in size
(hypertrophy), and not by increasing in number
(hyperplasia) (C). (A-B, D-E) are incorrect based on
the previously discussed information.
3
Q
- A 27-year-old male is in a car accident and sustains
a fracture of the 2nd thoracic vertebra, with
resultant damage to the spinal cord at the same level,
leading to paraplegia, requiring him to be wheelchair
bound. Five years following the accident, he develops
a neoplasm of the right lower extremity, requiring a
wide local excision, which includes a small superficial
segment of underlying skeletal muscle. When viewing
the microscopic slides, which of the following
would the pathologist identify in the skeletal muscle?
A. Physiologic hyperplasia
B. Pathologic hyperplasia
C. Physiologic hypertrophy
D. Pathologic hypertrophy
E. Physiologic atrophy
F. Pathologic atrophy
A
- Correct: Pathologic atrophy (F)
Damage to the spinal cord can lead to deinnervation
of the lower extremities. Deinnervation is one mechanism
causing atrophy, and, as the deinnervation
was due to a traumatic injury, the resultant atrophy
would be considered pathologic (F) and not physiologic
(E). As there is neither an increase in the size
of the skeletal muscle cells, nor an increase in their
number, the other answers are incorrect (A-D).
4
Q
- A pathologist is examining the biopsy of an individual’s
left ventricular myocardium and notices that
the cardiac myocytes are enlarged. Of the following
conditions, which would best explain this finding?
A. Pulmonary hypertension
B. Systemic hypertension
C. Lambl’s excresences on the aortic valve
D. A probe patent fossa ovalis
E. Acute pericardial hemorrhage
A
- Correct: Systemic hypertension (B)
The pathologist is viewing hypertrophy of the cardiac
myocytes. While identification of enlarged
cells themselves is a difficulty, enlarged rectangular
nuclei (i.e., boxcar nuclei) serve as a marker of cardiac
myocyte hypertrophy. Increased blood pressure
in the systemic vessels would put strain on the left
ventricle and lead to hypertrophy (B). Pulmonary
hypertension would cause similar changes in the
right ventricular myocardium (A). Lambl’s excrescences
are incidental small nodules on the valve
leaflets that are of no physiologic consequence (C).
A probe patent fossa ovalis is usually of no physiologic
significance (D). However, if a left to right shunt
developed, this condition could potentially lead to
volume overload in the right atrium and ventricle,
with resultant hypertrophy and dilation, but the left
ventricle would not be affected. An acute pericardial
hemorrhage would not explain hypertrophy, as
cardiac myocyte hypertrophy does not develop over
such a short period of time, but instead requires a
longer exposure to the stimulus (E).
5
Q
- A 2-year-old female aspirates a small coin, unbeknownst
to her caregivers. Over the next few days,
she develops a cough and becomes less responsive
and sleeps longer periods. Her parents also notice
that she feels warm to the touch, but do not take her
temperature. Six days following the coin being swallowed,
her parents find her unresponsive in her bedroom.
They call 9-1-1 and she is pronounced dead at
the hospital. Autopsy reveals a widespread bronchopneumonia
in the right lung and a coin lodged in the
right mainstem bronchus, nearly completely blocking
it. A microscopic section of the bronchus from
where the coin was lodged reveals stratified squamous
epithelium, which appears essentially normal,
similar to that seen in the inner lining of the esophagus.
Which of the following processes has occurred
in the bronchus?
A. Hypertrophy
B. Hyperplasia
C. Metaplasia
D. Atrophy
E. Irreversible cellular injury
A
- Correct: Metaplasia (C)
The bronchus is usually lined by respiratory epithelium
(pseudostratified columnar epithelium);
however, when the nature of the stimulus to the
epithelium changes, which, in this case is trauma
caused by the pressure from the coin, the epithelium
can change to a different form to better handle the
abnormal stimulus. The transition from one epithelium
type to another is termed metaplasia (C). In
the lung, squamous metaplasia most commonly is
a result of cigarette smoking, and, in this situation,
metaplasia can lead to dysplasia and finally to carcinoma,
accounting for the presence of squamous cell
carcinomas in the lung. If the coin is removed, the
epithelium could transition back to respiratory epithelium;
therefore, the change is reversible, and not
irreversible cellular injury. (A-B, D-E) are incorrect
based on the previously discussed information.
6
Q
- After developing hematuria and flank pain, a
55-year-old male is diagnosed with a renal cell carcinoma
in his right kidney. To treat the tumor, the
patient’s right kidney is resected. Five years later, he
dies in a car accident. At autopsy, there is an absence
of the right kidney, and the left kidney weighs 300
grams (normal weight is 150-200 grams for an adult
male). Of the following processes, which is most
likely occurring in the left kidney?
A. Physiologic hypertrophy
B. Pathologic hypertrophy
C. Physiologic hyperplasia, hormonal type
D. Physiologic hyperplasia, compensatory type
E. Pathologic hyperplasia
A
- Correct: Physiologic hyperplasia,
compensatory type (D)
Because of the absence of the right kidney, the left
kidney has a higher workload, and in response, the
left kidney increases the number of cells in its structure
to handle this increased workload and thus,
the organ weight has increased. The cells in the kidney
are capable of division, and thus hyperplasia
can occur (unlike in the cardiac or skeletal muscle).
The hyperplasia is physiologic in nature because
it is stimulated by an increased workload, and it is
to compensate for the loss of the other kidney (D).
(A-C, E) are incorrect based on previously discussed
information.
7
Q
- A 90-year-old male with severe dementia has
been bedridden for 5 years. Physical examination
reveals no decubitus ulcers on his back, buttocks,
or lower extremities; however, his upper and lower
extremities are reduced in circumference, the lower
extremities more so than the upper extremities,
with apparent significant loss of muscle mass. Which
of the following combinations of molecular mediators
is most responsible for the decreased size of the
skeletal muscles?
A. Cyclooxygenase-Thromboxane A2
B. 12-Lipooxygenase-Lipoxin A4
C. Plasmin-C3a
D. p53-Bax
E. Ubiquitin-proteosome
A
- Correct: Ubiquitin-proteasome (E)
The patient has disuse atrophy of the upper and
lower extremities. The two primary processes occurring
in atrophy are decreased protein synthesis and
increased protein degradation. Protein degradation
is accomplished by binding of ubiquitin to the substances
to be degraded followed by its subsequent
destruction by proteasomes (E). Cyclooxygenase and
thromboxane A2 and 12-lipooxygenase-lipoxin A4
function in inflammation (A, B), and plasmin-C3a
in the complement cascade (C), both of which could
be active in the muscle to some degree but are not
the main source of protein degradation, and p53-Bax
functions in apoptosis (D), which might be occurring
to some small degree but is not the main cause of the
protein degradation.
8
Q
- A 56-year-old male with a history of smoking
and hypertension develops an occlusive thrombus in
his left anterior descending coronary artery following
rupture of an atherosclerotic plaque. He survives
the event, but therapeutic lysis of the thrombus is
not accomplished until 1 hour after its formation. He
is told that he sustained a subendocardial myocardial
infarct. If a biopsy of the subendocardial myocytes
was performed 24 hours after the occlusion of the
vessel, of the following, which intracellular change
would be expected to be identified?
A. Swelling of the mitochondria
B. Dilation of the rough endoplasmic reticulum
C. Nuclear clumping of chromatin
D. Lipid vacuoles in the cytoplasm
E. Karyorrhexis of nuclei
A
- Correct: Karyorrhexis of nuclei (E)
After 1 hour of ischemia, some of the affected myocytes
would have irreversible damage, in this case,
represented by the subendocardial myocardial
infarct. Of the choices, only karyorrhexis of the
nuclei is characteristic of irreversible injury, i.e.,
necrosis (E), whereas the other choices are seen
with reversible injury (A-D). Other microscopic features
of irreversible ischemic injury (i.e., necrosis)
include increased eosinophilia of the cytoplasm, and
other nuclei changes including karyolysis (i.e., fading
of the chromatin) and pyknosis (i.e., shrinkage
of the nucleus). Karyorrhexis is fragmentation of the
nucleus. As the thrombus was lysed relatively early,
myocytes closer to the epicardium may have had
signs of reversible injury, but not irreversible injury.
9
Q
- The husband of a 62-year-old female found her
unresponsive on the couch in their apartment when
he returned home from work. Despite the efforts of
emergency responders, she was pronounced dead at
the hospital. An autopsy reveals a well-demarcated
wedge-shaped yellow lesion in the cortex of the left
kidney with preservation of normal gross architecture.
Of the following, what is the most likely etiology
for this autopsy finding?
A. Mycobacterium tuberculosis infection
B. Klebsiella bacterial infection
C. Renal cell carcinoma
D. Metastatic colonic adenocarcinoma
E. Thrombus of distal branch of left renal artery
A
- Correct: Thrombus of distal branch of left
renal artery (E)
The gross description is that of an infarct, which has
coagulative necrosis. In coagulative necrosis, the normal
organ architecture is preserved in the beginning
phases of the development of the infarct. A thrombus
of a branch of the renal artery can produce an infarct
of the cortex of the kidney (E). Infarcts are typically
wedge-shaped, essentially exhibiting the downstream
effects of a blockage of the arterial system,
with the amount of organ affected increasing moving
distal from a single point, the tip of the wedge.
Preservation of architecture does not occur with liquefactive
necrosis (as could be seen with a bacterial
pyelonephritis) or caseous necrosis (as could be seen
with a tuberculosis infection), and by their nature,
tumors do not have preservation of architecture
within their boundaries (A-D).
10
Q
- In his autopsy report, a pathologist describes a
5 x 3 cm focus of liquefactive necrosis. The source of
the liquefactive necrosis was a thrombus occluding an
artery, and the autopsy was performed 2 days following
the event that produced the liquefactive necrosis.
In which of the following sections of the autopsy
report would this lesion most likely be described?
A. Central nervous system
B. Cardiovascular system
C. Respiratory system
D. Hepatobiliary system
E. Genitourinary system
A
- Correct: Central nervous system (A)
In most organ systems, a thrombus will lead to ischemic
injury followed by coagulative necrosis (B-E);
however, in the brain, a thrombus and the resultant
ischemic injury produce liquefactive necrosis (A).
It should be noted that after an extended period of
time, areas of coagulative necrosis in organs other
than the brain can become liquefactive necrosis,
but this change would not be expected within only
2 days.
11
Q
- A 37-year-old male with a history of chronic
alcohol abuse and gallstones is brought to the emergency
room by a friend. The patient has been complaining
of severe abdominal pain for 3 days following
a bout of increased alcohol consumption. Laboratory
testing in the emergency room indicates an elevated
amylase and lipase. Despite treatment, the patient
dies. An autopsy of the individual most likely will
reveal which of the following in the greater omentum?
A. Coagulative necrosis
B. Liquefactive necrosis
C. Gangrenous necrosis
D. Caseous necrosis
E. Fat necrosis
F. Fibrinoid necrosis
A
- Correct: Fat necrosis (E)
Based on the clinical history (i.e., abdominal pain
with history of gallstones and alcohol abuse) and
laboratory testing (elevated amylase and lipase), the
individual most likely has acute pancreatitis, with
alcohol use and gallstones being two risk factors for
this condition, and with the symptomatology and
laboratory testing supporting this diagnosis. The
release of pancreatic enzymes damages adipose cells
in the peritoneal cavity (e.g., the omentum), and the
subsequently released fatty acids join with calcium
leading to small chalky white patches. This change
is termed fat necrosis (E). While examination of the
pancreas itself could reveal coagulative necrosis or,
depending on the time course of the inflammation,
liquefactive necrosis (A, B), these conditions would
not be the main condition identified in the omentum.
Gangrenous necrosis is found in the extremities,
and caseous necrosis is associated with tuberculosis
most commonly (C, D). A variety of conditions are
associated with fibrinoid necrosis, including some
forms of vasculitis, but it would not be present in the
omentum in this clinical scenario (F). - Correct: Sodium-potassium pump (C)
12
Q
- A pathologist is examining a section of kidney
and notes hydropic change in the proximal convoluted
tubule epithelial cells. Damage to or decreased
function of which of the following cellular structures
is most important in directly causing this finding?
A. Rough endoplasmic reticulum
B. Smooth endoplasmic reticulum
C. Sodium-potassium pump
D. Phagocyte oxidase
E. Cytoskeletal proteins
A
- Correct: Sodium-potassium pump (C)
Hydropic change, i.e., cellular swelling, is a sign of
reversible cellular injury. The sodium-potassium
pump normally pumps sodium out of the cell and
potassium into the cell. With ischemia, one cause
of reversible cellular injury, the amount of ATP produced
is reduced, and without ATP, the sodiumpotassium
pump will not function, allowing sodium
to enter the cell. Water follows sodium into the cell,
causing the cell to swell, and producing hydropic
change (C). (A-B, D-E) are incorrect based on the
previously discussed information.
13
Q
- For his research, a scientist exposes cultured
cells to certain forms of radiation. Following the exposure,
he can examine intracellular proteins for evidence
of cross-linking. Of the following, which has the
highest propensity for causing such protein changes?
A. Superoxide
B. Hydrogen peroxide
C. Hydroxyl radical
D. Nitric oxide
E. Oxidized glutathione
A
- Correct: Hydroxyl radical (C)
Superoxide, hydrogen peroxide, hydroxyl radical,
and nitric oxide are all reactive oxygen species (ROS),
which can cause cross-linking of proteins, lipid peroxidation,
and DNA damage. Oxidized glutathione is
produced in the breakdown of hydrogen peroxide.
The most reactive of the four ROS listed is hydroxyl
radical (C). (A-B, D-E) are incorrect based on the previously
discussed information.
14
Q
- A scientist is studying the effects of an experimental
medication, IST-151, on cultured hepatocytes.
The medication, unfortunately, results in the
death of the hepatocytes and appears to do so predominantly
through activation of an intracellular
endonuclease, which damages the nucleus of the cell,
leading to death. Of the following mechanisms of cellular
injury, which one is the most direct in mediating
the previously described effects (i.e., activation of
the endonuclease)?
A. Mitochondrial damage resulting in decreased
production of ATP
B. Mitochondrial damage leading to increased
production of reactive oxygen species
C. Calcium influx into the cell
D. Breakdown of lysosomal membranes
E. DNA damage leading to activation of proapoptotic
proteins
A
- Correct: Calcium influx into the cell (C)
The four main mechanisms by which cellular injury
occurs are 1) mitochondrial damage, 2) entry of calcium
into the cell, 3) damage to the plasma membrane
(causing dissolution of the cell), or 4) DNA
damage and/or protein misfolding, which can lead
to apoptosis. Calcium influx into the cell can activate
a variety of enzymes including phospholipases,
proteases, endonucleases, and ATPases (C). (A-B,
D-E) are incorrect based on the previously discussed
information.
15
Q
- A 46-year-old female receives radiation therapy
of the neck for a neoplasm of the thyroid gland.
After therapy, it is noted that her thyroid gland has
markedly decreased in size, leading to hypothyroidism,
and she must be placed on a thyroid replacement
therapeutic drug regimen. Of the following,
which statement is most characteristic regarding the
process by which the thyroid gland decreased in size?
A. The plasma membranes of the thyroid follicular
cells lysed
B. Prominent calcium influx led to marked
activation of phospholipase
C. Ischemic injury induced by the radiation led to
coagulative necrosis
D. Few, if any, inflammatory cells would have been
seen histologically
E. Damage to cytoskeletal elements led to
dissolution of the cells
A
- Correct: Few, if any, inflammatory cells
would have been seen histologically (D).
Radiation causes damage to DNA, which can trigger
the process of apoptosis. During apoptosis, the
cells break down into fragments, each with an intact
membrane, and little, if, any inflammation is triggered
(D). (A-C, E) are incorrect. See previously discussed
information.
