1. Cellular Pathology

Question 1

1. A 17-year-old boy infected with hepatitis A experiences mild nausea for about 1 week and develops very mild scleral icterus. On physical examination, he has minimal right upper quadrant tenderness. Laboratory findings include a serum AST of 68 U/L, ALT of 75 U/L, and total bilirubin of 5.1 mg/dL. The increase in this patient’s serum enzyme levels most likely results from which of the following changes in the hepatocytes?

□ (A) Autophagy by lysosomes

□ (B) Clumping of nuclear chromatin

□ (C) Defects in the cell membrane

□ (D) Dispersion of ribosomes

□ (E) Swelling of the mitochondria

Answer 1

(C) Defects in the cell membrane

(Irreversible cell injury is associated with loss of membrane integrity. This allows intracellular enzymes to leak into the serum. All other morphologic changes listed are associated with reversible cell injury, in which the cell membrane remains intact.)

Question 2

2. A 16-year-old boy sustained blunt trauma to the abdomen when the vehicle he was driving struck a bridge abutment at high speed. Peritoneal lavage shows a hemoperitoneum, and at laparotomy, a small portion of the left lobe of the liver is removed because of the injury. Several weeks later, a CT scan of the abdomen shows that the liver has nearly regained its size before the injury. Which of the following processes best explains this CT scan finding?

□ (A) Apoptosis

□ (B) Dysplasia

□ (C) Fatty change

□ (D) Hydropic change

□ (E) Hyperplasia

□ (F) Hypertrophy

□ (G) Metaplasia

Answer 2

□ (E) Hyperplasia

(The liver is one of the few organs in the human body that can partially regenerate. This is a form of compensatory hyperplasia. The stimuli to hepatocyte mitotic activity cease when the liver has attained its normal size. Apoptosis is single cell death and frequently occurs with viral hepatitis. Dysplasia is disordered epithelial cell growth that can be premalignant. Fatty change can lead to hepatomegaly; this is not a regenerative process, but is the result of toxic hepatocyte injury. Hydropic change, or cell swelling, does not produce regeneration. Hepatocytes can reenter the cell cycle and proliferate to regenerate the liver; they do not just increase in size.)

Question 3

3. On a routine visit to the physician, an otherwise healthy 51-year-old man has a blood pressure of 150/95 mm Hg. If his hypertension remains untreated for years, which of the following cellular alterations would most likely be seen in his myocardium?

□ (A) Atrophy

□ (B) Hyperplasia

□ (C) Metaplasia

□ (D) Hemosiderosis

□ (E) Hypertrophy

Answer 3

□ (E) Hypertrophy

(The pressure load on the left ventricle results in an increase in myofilaments in the existing myofibers. The result of continued stress from hypertension is eventual heart failure with decreased contractility, but the cells do not decrease in size. Metaplasia of muscle does not occur, although loss of muscle occurs with aging as myofibers are replaced by fibrous tissue and adipose tissue. Hemosiderin deposition in the heart is a pathologic process resulting from increased iron stores in the body.)

Question 4

4. A 72-year-old man died suddenly from congestive heart failure. At autopsy, the heart weighed 580 g and showed marked left ventricular hypertrophy and minimal coronary arterial atherosclerosis. A serum chemistry panel ordered before death showed no abnormalities. Which of the following pathologic processes best accounts for the appearance of the aortic valve seen in the figure?

□ (A) Amyloidosis

□ (B) Dystrophic calcification

□ (C) Lipofuscin deposition

□ (D) Hemosiderosis

□ (E) Fatty change

Answer 4

□ (B) Dystrophic calcification

(The valve is stenotic because of nodular deposits of calcium. The process is “dystrophic” because calcium deposition occurs in damaged tissues. The damage in this patient is a result of the wear and tear of aging. Amyloid deposition in the heart typically occurs within the myocardium and the vessels. The amount of lipofuscin increases within myocardial fibers (not valves) with aging. Hereditary hemochromatosis is a genetic defect in iron absorption that results in extensive myocardial iron deposition (hemosiderosis). Fatty change is uncommonly seen in myocardium, but infiltration of fat cells between myofibers can occur.)

Question 5

5. A 69-year-old woman has had transient ischemic attacks for the past 3 months. On physical examination, she has an audible bruit on auscultation of the neck. A right carotid endarterectomy is performed. The curetted atheromatous plaque has a grossly yellow-tan, firm appearance. Microscopically, which of the following materials can be found in abundance in the form of crystals that produce long, cleft-like spaces?

□ (A) Glycogen

□ (B) Lipofuscin

□ (C) Hemosiderin

□ (D) Immunoglobulin

□ (E) Cholesterol

Answer 5

□ (E) Cholesterol

(Cholesterol is a form of lipid commonly deposited within atheromas in arterial walls, imparting a yellow color to these plaques. Glycogen is a storage form of carbohydrate seen mainly in liver and muscle. Lipofuscin is a brown pigment that increases with aging in cell cytoplasm, mainly in cardiac myocytes and in hepatocytes. Hemosiderin is a storage form of iron that appears in tissues of the mononuclear phagocyte system (e.g., marrow, liver, spleen), but can be widely deposited with hereditary hemochromatosis. Immunoglobulin occasionally may be seen as rounded globules in plasma cells (i.e., Russell bodies).)

Question 6

6. A 38-year-old woman experienced severe abdominal pain with hypotension and shock that led to her death within 36 hours after the onset of the pain. From the gross appearance of the mesentery, seen in the figure at the bottom of the previous column, which of the following events has most likely occurred?

□ (A) Hepatitis B virus infection

□ (B) Small intestinal infarction

□ (C) Tuberculous lymphadenitis

□ (D) Gangrenous cholecystitis

□ (E) Acute pancreatitis

Answer 6

□ (E) Acute pancreatitis

(The focal, chalky white deposits are areas of fat necrosis resulting from the release of pancreatic lipases in a patient with acute pancreatitis. Viral hepatitis does not cause necrosis in other organs, and hepatocyte necrosis from viral infections occurs mainly by means of apoptosis. Intestinal infarction is a form of coagulative necrosis. Tuberculosis produces caseous necrosis. Gangrenous necrosis is mainly coagulative necrosis, but occurs over an extensive area.)

Question 7

7. In an experiment, cells are subjected to radiant energy in the form of x-rays. This results in cell injury caused by hydrolysis of water. Which of the following cellular enzymes protects the cells from this type of injury?

□ (A) Phospholipase

□ (B) Glutathione peroxidase

□ (C) Endonuclease

□ (D) Lactate dehydrogenase

□ (E) Protease

Answer 7

□ (B) Glutathione peroxidase

(Intracellular mechanisms exist that deal with free radical generation, as can occur with radiant injury from irradiation. Glutathione peroxidase reduces such injury by catalyzing the breakdown of hydrogen peroxide. Phospholipases decrease cellular phospholipids and promote cell membrane injury. Proteases can damage cell membranes and cytoskeletal proteins. Endonucleases damage nuclear chromatin. Lactate dehydrogenase is present in a variety of cells, and its elevation in the serum is an indicator of cell death.)

Question 8

8. A 47-year-old woman has had worsening dyspnea for the past 5 years. A chest CT scan shows panlobular emphysema. Laboratory studies show the PiZZ genotype of α1-antitrypsin (AAT) deficiency. A liver biopsy specimen examined microscopically shows abundant PAS-positive globules within periportal hepatocytes. Which of the following molecular mechanisms is most likely responsible for this finding in the hepatocytes?

□ (A) Excessive hepatic synthesis of AAT

□ (B) Retention of poorly folded AAT in the endoplasmic reticulum

□ (C) Decreased catabolism of AAT in lysosomes

□ (D) Inability to metabolize AAT

□ (E) Impaired dissociation of AAT from chaperones

Answer 8

□ (B) Retention of poorly folded AAT in the endoplasmic reticulum

(Mutations in the AAT gene give rise to AAT molecules that cannot fold properly. In the PiZZ genotype, both alleles have the mutation. The partially folded molecules accumulate in the endoplasmic reticulum and cannot be secreted. Impaired dissociation of the CFTR protein from chaperones causes many cases of cystic fibrosis. There is no abnormality in the synthesis, catabolism, or metabolism of AAT in patients with AAT deficiency.)

Question 9

9. A 68-year-old woman suddenly lost consciousness; on awakening 1 hour later, she could not speak or move her right arm and leg. Two months later, a head CT scan showed a large cystic area in the left parietal lobe. Which of the following pathologic processes has most likely occurred in the brain?

□ (A) Fat necrosis

□ (B) Coagulative necrosis

□ (C) Apoptosis

□ (D) Liquefactive necrosis

□ (E) Karyolysis

Answer 9

□ (D) Liquefactive necrosis

(The high lipid content of central nervous system tissues results in liquefactive necrosis as a consequence of ischemic injury, as in this case of a “stroke.” Fat necrosis is seen in breast and pancreatic tissues. Coagulative necrosis is the typical result of ischemia in most solid organs. Apoptosis affects single cells and typically is not grossly visible. Karyolysis refers to fading away of cell nuclei in dead cells.)

Question 10

10. A 30-year-old man sustains a left femoral fracture in a skiing accident, and his leg is placed in a plaster cast. After the leg has been immobilized for several weeks, the diameter of the left calf has decreased. This change is most likely to result from which of the following alterations in the calf muscles?

□ (A) Aplasia

□ (B) Hypoplasia

□ (C) Atrophy

□ (D) Dystrophy

□ (E) Hyalinosis

Answer 10

□ (C) Atrophy

(Reduced workload causes shrinkage of cell size because of loss of cell substance, a process called atrophy. Aplasia refers to lack of embryonic development; hypoplasia describes poor or subnormal development. Dystrophy of muscles refers to inherited disorders of skeletal muscles that lead to muscle weakness and wasting. Hyaline change (hyalinosis) refers to a nonspecific, pink, glassy eosinophilic appearance of cells.)

Question 11

11. An experiment analyzes cells for enzyme activity associated with sustained cellular proliferation. Which of the following cells is most likely to have the highest telomerase activity?

□ (A) Endothelial cells

□ (B) Germ cells

□ (C) Neurons

□ (D) Neutrophils

□ (E) Erythrocytes

Answer 11

□ (B) Germ cells

(Germ cells have the highest telomerase activity, and the telomere length can be stabilized in these cells. This allows testicular germ cells to retain the ability to divide throughout life. Normal somatic cells have no telomerase activity, and telomeres progressively shorten with each cell division until growth arrest occurs.)

Question 12

12. A 32-year-old man experiences “heartburn” and gastric reflux after eating a large meal. After many months of symptoms, he undergoes upper gastrointestinal endoscopy, and a biopsy specimen of the esophageal epithelium is obtained. Which of the following pathologic changes, seen in the figure, has most likely occurred?

□ (A) Squamous metaplasia

□ (B) Mucosal hypertrophy

□ (C) Columnar epithelial metaplasia

□ (D) Atrophy of lamina propria

□ (E) Goblet cell hyperplasia

Answer 12

□ (C) Columnar epithelial metaplasia

(Inflammation from reflux of gastric acid has resulted in replacement of normal esophageal squamous epithelium by intestinal-type columnar epithelium with goblet cells. Such conversion of one adult cell type to another cell type is called metaplasia. The cells are not significantly increased in size (hypertrophic). The lamina propria has some inflammatory cells, but is not atrophic. Goblet cells are not normal constituents of the esophageal mucosa.)

Question 13

13. On day 28 of her menstrual cycle, a 23-year-old woman experiences onset of menstrual bleeding that lasts for 6 days. She has had regular cycles for many years. Which of the following processes is most likely occurring in the endometrium just before the onset of bleeding?

□ (A) Apoptosis

□ (B) Caseous necrosis

□ (C) Heterophagocytosis

□ (D) Atrophy

□ (E) Liquefactive necrosis

Answer 13

□ (A) Apoptosis

(The onset of menstruation is an example of orderly, programmed cell death (apoptosis) through hormonal stimuli. The endometrium breaks down, sloughs off, and then regenerates. Caseous necrosis is typical of granulomatous inflammation, resulting most commonly from mycobacterial infection. Heterophagocytosis is typified by the clearing of an area of necrosis through macrophage ingestion of the necrotic cells. With cellular atrophy, there is often no visible necrosis, but the tissues shrink, something that occurs in the endometrium after menopause. Liquefactive necrosis can occur in any tissue after acute bacterial infection or in the brain after ischemia.)

Question 14

14. In a clinical trial, a chemotherapeutic agent is given to patients with breast cancer metastases. Samples of the cancer cells are obtained and assessed for the presence of death of tumor cells by apoptosis. Mutational inactivation of which of the following products is most likely to render tumor cells resistant to the effects of such an agent?

□ (A) BCL-2

□ (B) p53

□ (C) NF-κB

□ (D) Cytochrome P-450

□ (E) Granzyme B

Answer 14

□ (B) p53

(When DNA damage is induced by chemotherapeutic drugs (or other agents), normal p53 genes trigger the cells to undergo apoptosis. When p53 is inactivated, this pathway of cell death can be blocked, rendering the chemotherapy less effective. BCL-2 and NF-κB activity favor cell survival. Cytochrome P-450 does not affect apoptosis. Granzyme B can trigger apoptosis, but it is found in cytotoxic T cells and not in tumor cells.)

Question 15

15. After the birth of her first child, a 19-year-old woman breastfed the infant for about 1 year. Which of the following processes that occurred in the breast during pregnancy allowed her to breastfeed the infant?

□ (A) Stromal hypertrophy

□ (B) Lobular hyperplasia

□ (C) Epithelial dysplasia

□ (D) Intracellular accumulation of fat

□ (E) Ductal epithelial metaplasia

Answer 15

□ (B) Lobular hyperplasia

(Lobules increase under hormonal influence (mainly progesterone) to provide for normal lactation. The breast stroma plays no role in lactation and may increase with pathologic processes. Epithelial dysplasia denotes disordered growth and maturation of epithelial cells that may progress to cancer. Accumulation of fat within cells is a common manifestation of sublethal cell injury or, uncommonly, of inborn errors in fat metabolism. Epithelial metaplasia in the breast is a pathologic process.)

Question 16

16. A 22-year-old woman has a congenital anemia that has required multiple transfusions of RBCs for many years. On physical examination, she now has no significant findings; however, liver function tests show reduced serum albumin. Which of the following findings would most likely appear in a liver biopsy specimen?

□ (A) Steatosis in hepatocytes

□ (B) Bilirubin in canaliculi

□ (C) Glycogen in hepatocytes

□ (D) Amyloid in portal triads

□ (E) Hemosiderin in hepatocytes

Answer 16

□ (E) Hemosiderin in hepatocytes

(Each unit of blood contains about 250 mg of iron. The body has no mechanism for getting rid of excess iron. About 10 to 20 mg of iron per day is lost with normal desquamation of epithelia; menstruating women lose slightly more. Any excess iron becomes storage iron, or hemosiderin. Over time, hemosiderosis involves more and more tissues of the body, particularly the liver. Initially, hemosiderin deposits are found in Kupffer cells and other mononuclear phagocytes in the bone marrow, spleen, and lymph nodes. With great excess of iron, liver cells also accumulate iron. Steatosis usually occurs with ingestion of hepatotoxins, such as alcohol. Bilirubin, a breakdown product of blood, can be excreted in the bile so that a person does not become jaundiced. Glycogen storage diseases are inherited and present in childhood. Amyloid is an abnormal protein derived from a variety of precursors, such as immunoglobulin light chains.)

Question 17

17. A 50-year-old man experienced an episode of chest pain 6 hours before his death. A histologic section of left ventricular myocardium taken at autopsy showed a deeply eosinophilic-staining area with loss of nuclei and cross-striations in myocardial fibers. There was no hemorrhage or inflammation. Which of the following conditions most likely produced these myocardial changes?

□ (A) Viral infection

□ (B) Coronary artery thrombosis

□ (C) Blunt chest trauma

□ (D) Antibodies directed against myocardium

□ (E) Protein-deficient diet

Answer 17

□ (B) Coronary artery thrombosis

(The deep eosinophilic staining, loss of nuclei, and loss of cell structure suggest an early ischemic injury, resulting in coagulative necrosis. This finding is typically caused by loss of blood flow. Viral infection could cause necrosis of the myocardium, but this is usually accompanied by an inflammatory infiltrate consisting of lymphocytes and macrophages. Blunt trauma produces hemorrhage. An immunological injury may produce focal cell injury, but not widespread ischemic injury. Lack of protein leads to a catabolic state with gradual decrease in cell size, but it does not cause ischemic changes.)

Question 18

18. A 69-year-old man has had difficulty with urination, including hesitancy and frequency, for the past 5 years. A digital rectal examination reveals that the prostate gland is palpably enlarged to about twice normal size. A transurethral resection of the prostate is performed, and the microscopic appearance of the prostate “chips” obtained is that of nodules of glands with intervening stroma. Which of the following pathologic processes has most likely occurred in the prostate?

□ (A) Apoptosis

□ (B) Dysplasia

□ (C) Fatty change

□ (D) Hyperplasia

□ (E) Hypertrophy

□ (F) Metaplasia

Answer 18

□ (D) Hyperplasia

(Nodular prostatic hyperplasia (also known as benign prostatic hyperplasia [BPH]) is a common condition in older men that results from proliferation of prostatic glands and stroma. The prostate becomes more sensitive to androgenic stimulation with age. This is an example of pathologic hyperplasia. Apoptosis results in a loss of, not an increase in, cells. Dysplasia refers to disordered epithelial cell growth and maturation. Fatty change in hepatocytes may produce hepatomegaly. Although BPH is often called “benign prostatic hypertrophy,” this term is technically incorrect; it is the number of glands and stromal cells that is increased, rather than the size of existing cells. A change in the glandular epithelium to squamous epithelium would be an example of metaplasia.)

Question 19

19. A 54-year-old man experienced onset of severe substernal chest pain over 3 hours. An ECG showed changes consistent with an acute myocardial infarction. After thrombolytic therapy with tissue plasminogen activator (t-PA), his serum creatine kinase (CK) level increased. Which of the following events most likely occurred after t-PA therapy?

□ (A) Reperfusion injury

□ (B) Cellular regeneration

□ (C) Chemical injury

□ (D) Increased synthesis of CK

□ (E) Myofiber atrophy

Answer 19

□ (A) Reperfusion injury

(If the existing cell damage is not great after myocardial infarction, the restoration of blood flow can help prevent further damage. The reperfusion of damaged cells results in generation of oxygen-derived free radicals, however, causing a reperfusion injury. The elevation in the CK level is indicative of myocardial cell necrosis because this intracellular enzyme does not leak in large quantities from intact cells. Myocardial fibers do not regenerate to a significant degree, and atrophic fibers would have less enzyme to release. t-PA does not produce a chemical injury; it induces thrombolysis to restore blood flow in blocked coronary arteries.)

Question 20

20. A 33-year-old woman has had increasing lethargy and decreased urine output for the past week. Laboratory studies show serum creatinine level of 4.3 mg/dL and urea nitrogen level of 40 mg/dL. A renal biopsy is performed, and the specimen is examined using electron microscopy. Which of the following morphologic changes most likely suggests a diagnosis of acute tubular necrosis?

□ (A) Mitochondrial swelling

□ (B) Plasma membrane blebs

□ (C) Chromatin clumping

□ (D) Nuclear fragmentation

□ (E) Ribosomal disaggregation

Answer 20

□ (D) Nuclear fragmentation

(Loss of the nucleus results in cell death. All other cellular morphologic changes listed represent reversible cellular injury. The plasma membrane and intracellular organelles remain functional unless severe damage causes loss of membrane integrity.)

Question 21

21. A 40-year-old man had undifferentiated carcinoma of the lung. Despite chemotherapy, the man died of widespread metastases. At autopsy, tumors were found in many organs. Histologic examination showed many foci in which individual tumor cells appeared shrunken and deeply eosinophilic. Their nuclei exhibited condensed aggregates of chromatin under the nuclear membrane. The process affecting these shrunken tumor cells was most likely triggered by the release of which of the following substances into the cytosol?

□ (A) Lipofuscin

□ (B) Cytochrome c

□ (C) Catalase

□ (D) Phospholipase

□ (E) BCL-2

Answer 21

□ (B) Cytochrome c

(This histologic picture is typical of apoptosis produced by chemotherapeutic agents. The release of cytochrome from the mitochondria is a key step in many forms of apoptosis, and it leads to the activation of caspases. BCL-2 is an antiapoptotic protein that prevents cytochrome c release and prevents caspase activation. Lipofuscin is a pigmented residue representing undigested cellular organelles in autophagic vacuoles. Catalase is a scavenger of hydrogen peroxide. Phospholipases are activated during necrosis and cause cell membrane damage.)

Question 22

22. A 70-year-old man died suddenly. At autopsy, multiple tissue sites were sampled for microscopic analysis. Examination of the tissues showed noncrystalline amorphous deposits of calcium salts in gastric mucosa, renal interstitium, and alveolar walls of lungs. Which of the following conditions would most likely explain these findings?

□ (A) Chronic hepatitis

□ (B) Chronic glomerulonephritis

□ (C) Disseminated tuberculosis

□ (D) Generalized atherosclerosis

□ (E) Normal aging process

□ (F) Pulmonary emphysema

Answer 22

□ (B) Chronic glomerulonephritis

(The microscopic findings suggest metastatic calcification, with deposition of calcium salts in tissues that have physiologic mechanisms for losing acid, creating an internal alkaline environment that favors calcium precipitation. Hypercalcemia can have a variety of causes, including hyperparathyroidism, bone destruction secondary to metastases, paraneoplastic syndromes, and, less commonly, vitamin D toxicity or sarcoidosis. Chronic renal disease reduces phosphate excretion by the kidney, resulting in an increase in serum phosphate. Because the solubility product of calcium and phosphorus must be maintained, the serum calcium is depressed, triggering increased parathyroid hormone output to increase the calcium level, which promotes calcium deposition. Chronic hepatitis leads to hyperbilirubinemia and jaundice. The granulomas of tuberculosis have caseous necrosis with dystrophic calcification. Another form of dystrophic calcification occurs when atherosclerotic lesions calcify. Dystrophic calcification is seen more often in the elderly, but it is the result of a lifetime of pathologic changes, not aging itself. Pulmonary emphysema can lead to respiratory acidosis that is compensated by metabolic alkalosis, with the result that the serum calcium level remains relatively unchanged.)

Question 23

23. A 63-year-old man has a 2-year history of worsening congestive heart failure. An echocardiogram shows mitral stenosis with left atrial dilation. A thrombus is present in the left atrium. One month later, he experiences left flank pain and notes hematuria. Laboratory testing shows elevated serum AST. Which of the following patterns of tissue injury is most likely to be present?

□ (A) Liquefactive necrosis

□ (B) Caseous necrosis

□ (C) Coagulative necrosis

□ (D) Fat necrosis

□ (E) Gangrenous necrosis

Answer 23

□ (C) Coagulative necrosis

(Embolization of the thrombus led to blockage of a renal arterial branch, causing an acute renal infarction in this patient. An ischemic injury to most internal organs produces a pattern of cell death called coagulative necrosis. Liquefactive necrosis occurs after ischemic injury to the brain and is the pattern seen with abscess formation. Caseous necrosis can be seen in various forms of granulomatous inflammation, typified by tuberculosis. Fat necrosis is usually seen in pancreatic and breast tissue. Gangrenous necrosis is a form of coagulative necrosis that usually results from ischemia and affects limbs.)

Question 24

24. At autopsy, a 40-year-old man has an enlarged (2200 g) liver with a yellow cut surface. The microscopic appearance of this liver is shown in the figure. Before death, the man’s total serum cholesterol and triglyceride levels were normal, but he had a decreased serum albumin concentration and increased prothrombin time. Which of the following activities most likely led to these findings?

□ (A) Injecting heroin

□ (B) Playing basketball

□ (C) Drinking beer

□ (D) Smoking cigarettes

□ (E) Ingesting aspirin

Answer 24

□ (C) Drinking beer

(The appearance of lipid vacuoles in many of the hepatocytes is characteristic of fatty change (steatosis) of the liver. Abnormalities in lipoprotein metabolism can lead to steatosis. Alcohol is a hepatotoxin that produces hepatic steatosis. Decreased serum albumin levels and increased prothrombin time suggest alcohol-induced hepatocyte damage. Substance abuse with heroin produces few organ-specific pathologic findings. Exercise has little direct effect on hepatic function. Smoking directly damages lung tissue, but has no direct effect on the liver. Aspirin has a significant effect on platelet function, but not on hepatocytes.)

Question 25

25. A 22-year-old woman with leukemia undergoes bone marrow transplantation and receives partially mismatched donor marrow. One month later, she has a scaling skin rash. Examination of a skin biopsy specimen reveals the cellular change shown in the figure. This change most likely results from which of the following biochemical reactions?

□ (A) Activation of caspases

□ (B) Reduction of ATP synthesis

□ (C) Increase in glycolysis

□ (D) Activation of lipases

□ (E) Lipid peroxidation

Answer 25

□ (A) Activation of caspases

(This cell is shrunken and has been converted into a dense eosinophilic mass. The surrounding cells are normal, and there is no inflammatory reaction. This pattern is typical of apoptosis. Caspase activation is a universal feature of apoptosis, regardless of the initiating cause. Apoptosis induced in recipient cells from donor lymphocytes occurs with graft- versus-host disease. Reduced ATP synthesis and increased glycolysis occur when a cell is subjected to anoxia. These changes are reversible. Lipases are activated in enzymatic fat necrosis. Lipid peroxidation occurs when the cell is injured by free radicals.)

Question 26

26. At autopsy, the heart of a 63-year-old man weighs only 250 g and has small right and left ventricles. The myocardium is firm, with a dark chocolate-brown color throughout. The coronary arteries show minimal atherosclerotic changes. An excessive amount of which of the following substances would most likely be found in the myocardial fibers of this heart?

□ (A) Melanin

□ (B) Hemosiderin

□ (C) Glycogen

□ (D) Lipofuscin

□ (E) Bilirubin

Answer 26

□ (D) Lipofuscin

(Lipofuscin is a “wear-and-tear” pigment that increases with aging, particularly in liver and myocardium. The pigment has minimal effect on cellular function in most cases. Rarely, there is marked lipofuscin deposition in a small heart, a so-called brown atrophy. Melanin pigment is responsible for skin tone: the more melanin, the darker the skin. Hemosiderin is the breakdown product of hemoglobin that contains the iron. Hearts with excessive iron deposition tend to be large. Glycogen is increased in some inherited enzyme disorders, and when the heart is involved, heart size increases. Bilirubin, another breakdown product of hemoglobin, imparts a yellow appearance (icterus) to tissues.)

Question 27

27. A 69-year-old woman has had a chronic cough for the past year. A chest radiograph shows a 6-cm mass in the left lung, and a needle biopsy specimen of the mass shows carcinoma. A pneumonectomy is performed, and examination of the hilar lymph nodes reveals a uniform, dark black cut surface. Which of the following factors most likely accounts for the appearance of the lymph nodes?

□ (A) Smoking

□ (B) Bleeding disorder

□ (C) Liver failure

□ (D) Aging

□ (E) Metastases

Answer 27

□ (A) Smoking

(Anthracotic pigmentation is common in lung and hilar lymph nodes and occurs when carbon pigment is inhaled from polluted air. The tar in cigarette smoke is a major source of such carbonaceous pigment. Resolution of hemorrhage can produce hemosiderin pigmentation, which imparts a brown color to tissues. Hepatic failure may result in jaundice, characterized by a yellow color. Older individuals generally have more anthracotic pigment, but this is not inevitable with aging—individuals living in rural areas with good environmental air quality have less pigment. Metastases impart a tan-to- white appearance to tissues.)

Question 28

28. A 44-year-old man has a history of poorly controlled diabetes mellitus leading to coronary artery disease. He now has decreasing cardiac output. An increase in which of the following substances in his blood is most indicative of reversible cell injury from decreased perfusion of multiple organs and tissues?

□ (A) Carbon dioxide

□ (B) Creatinine

□ (C) Glucose

□ (D) Lactic acid

□ (E) Troponin I

Answer 28

□ (D) Lactic acid

(Decreased tissue perfusion leads to hypoxemia and depletion of ATP when cell metabolism shifts from aerobic to anaerobic glycolysis, resulting in depletion of glycogen stores and increased production and accumulation of lactic acid, reducing intracellular pH. Creatinine would increase with reduced renal function from decreased renal perfusion, but this would not explain the changes in other tissues. An increased glucose would be indicative of poorly controlled diabetes mellitus, not decreased perfusion. Carbon dioxide is likely to be cleared via the lungs, which are still sufficiently perfused. An increase in troponin I suggests irreversible myocardial injury.)

Question 29

29. An experiment introduces a “knockout” gene mutation into a cell line. The frequency of shrunken cells with chromatin clumping and cytoplasmic blebbing is increased compared with a cell line without the mutation. Overall survival of the mutant cell line is reduced. Which of the following genes is most likely to be affected by this mutation?

□ (A) BAX

□ (B) BCL-2

□ (C) C-MYC

□ (D) FAS

□ (E) p53

Answer 29

□ (B) BCL-2

(These histologic findings are typical of apopotosis. The BCL-2 gene product inhibits cellular apoptosis by binding to Apaf-1. The BAX gene product promotes apoptosis. The C-MYC gene is involved with oncogenesis. The FAS gene encodes for a cellular receptor for FAS ligand, which signals apoptosis. p53 gene activity normally stimulates apoptosis, but mutation favors cell survival.)

Question 30

30. A tissue preparation is experimentally subjected to a hypoxic environment. The cells in this tissue begin to swell, and chromatin begins to clump in the nucleus. ATPases are activated, and ATP production decreases. Which of the following ions released from mitochondria leads to these findings and to eventual cell death?

□ (A) Ca2+

□ (B) Cl−

□ (C) HCO32−

□ (D) K+

□ (E) Na+

□ (F) PO42+

Answer 30

□ (A) Ca2+

(Irreversible cellular injury is likely to occur when calcium increases within cells. This calcium can influx into cells and be released from mitochondria and endoplasmic reticulum. The calcium activates ATPases, phospholipases, proteases, and endonucleases, which injure cell components. Mitochondrial permeability is increased to release cytochrome c, which activates caspases leading to apoptosis. Of the other ions listed, sodium influxes into the cell, while potassium diffuses out when the sodium pump fails as ATP levels fall, but this is potentially reversible.)

Question 31

31. A chest radiograph of an asymptomatic 37-year-old man showed a 3-cm nodule in the middle lobe of the right lung. The nodule was excised with a pulmonary wedge resection, and sectioning showed the nodule to be sharply circumscribed with a soft, white center. Culture of tissue from the nodule grew Mycobacterium tuberculosis. Which of the following pathologic processes has most likely occurred in this nodule?

□ (A) Apoptosis

□ (B) Caseous necrosis

□ (C) Coagulative necrosis

□ (D) Fat necrosis

□ (E) Fatty change

□ (F) Gangrenous necrosis

□ (G) Liquefactive necrosis

Answer 31

□ (B) Caseous necrosis

(The cheese-like appearance gives this form of necrosis its name—caseous necrosis. In the lung, tuberculosis and fungal infections are most likely to produce this pattern of tissue injury. Apoptosis involves individual cells, without extensive or localized areas of tissue necrosis. Coagulative necrosis is more typical of ischemic tissue injury. Fat necrosis most often occurs in the breast and pancreas. Fatty change is most often a feature of hepatocyte injury, and the cell integrity is maintained. Gangrene characterizes extensive necrosis of multiple cell types in a body region or organ. Liquefactive necrosis is seen in abscesses or ischemic cerebral injury.)

Question 32

32. The nonpregnant uterus of a 20-year-old woman measures 7 × 4 × 3 cm. The woman becomes pregnant and just before delivery of a term infant, the uterus measures 34 × 18 × 12 cm. Which of the following cellular processes has contributed most to the increase in uterine size?

□ (A) Endometrial glandular hyperplasia

□ (B) Myometrial fibroblast proliferation

□ (C) Endometrial stromal hypertrophy

□ (D) Myometrial smooth muscle hypertrophy

□ (E) Vascular endothelial hyperplasia

Answer 32

□ (D) Myometrial smooth muscle hypertrophy

(The increase in uterine size is primarily the result of an increase in myometrial smooth muscle cell size. The endometrium also increases in size, but it remains as a lining to the muscular wall and does not contribute as much to the change in size. There is little stroma in myometrium and a greater proportion in endometrium, but this contributes a smaller percentage to the gain in size than muscle. The vessels are a minor but essential component in this process.)

Question 33

33. A 40-year-old woman has had chronic congestive heart failure for the past 3 years. In the past 2 months, she developed a cough productive of rust-colored sputum. A sputum cytology specimen shows numerous hemosiderin-laden macrophages. Which of the following subcellular structures in macrophages is most important for the accumulation of this pigment?

□ (A) Lysosome

□ (B) Endoplasmic reticulum

□ (C) Ribosome

□ (D) Golgi apparatus

□ (E) Chromosome

Answer 33

□ (A) Lysosome

(Heterophagocytosis by macrophages requires that endocytosed vacuoles fuse with lysosomes to degrade the engulfed material. With congestive failure, extravasation of RBCs into alveoli occurs, and pulmonary macrophages must phagocytose the RBCs, breaking down the hemoglobin and recycling the iron by hemosiderin formation.)

Question 34

34. In an experiment, a large amount of a drug is administered to subjects and is converted by cytochrome P-450 to a toxic metabolite. The accumulation of this metabolite leads to increased lipid peroxidation within cells, causing damage to cell membranes and cell swelling. Depletion of which of the following substances by this mechanism within the cytosol exacerbates the cellular injury?

□ (A) ADP

□ (B) Calcium

□ (C) Glutathione

□ (D) NADPH oxidase

□ (E) Nitric oxide synthase

□ (F) mRNA

□ (G) Sodium

Answer 34

□ (C) Glutathione

(Glutathione in the cytosol helps to reduce cellular injury from many toxic metabolites and free radicals. ADP is converted to ATP by oxidative and glycolytic cellular pathways to provide energy that drives cellular functions, and a reduction in ATP leaves the cell vulnerable to injury. Calcium influx into a cell promotes injury. NADPH oxidase generates superoxide, which is used by neutrophils in killing bacteria. Nitric oxide synthase in macrophages produces nitric oxide, which aids in destroying organisms undergoing phagocytosis. Protein synthesis in cells depends on mRNA for longer survival and to recover from damage from free radicals. Failure of the sodium pump leads to increased cytosolic sodium and cell swelling with injury.)

Question 35

35. An experiment is conducted in which cells in tissue culture are subjected to high levels of ultraviolet radiant energy. Electron microscopy shows cellular damage in the form of increased cytosolic aggregates of denatured proteins. In situ hybridization reveals that protein components in these aggregates also are found in proteasomes. Which of the following substances is most likely to bind to the denatured proteins, targeting them for catabolism by cytosolic proteasomes?

□ (A) Adenosine monophosphate

□ (B) Calcium

□ (C) Caspase

□ (D) Granzyme B

□ (E) Hydrogen peroxide

□ (F) Ubiquitin

Answer 35

□ (F) Ubiquitin

(Heat-shock proteins provide for a variety of cellular “housekeeping” activities, including recycling and restoration of damaged proteins and removal of denatured proteins. Ubiquitin targets denatured proteins and facilitates their binding to proteasomes, which then break down the proteins to peptides. ADP increases when ATP is depleted, helping to drive anaerobic glycolysis. Cytosolic calcium levels may increase with cell injury that depletes ATP; the calcium activates phospholipases, endonucleases, and proteases, which damage the cell membranes, structural proteins, and mitochondria. Caspases are enzymes that facilitate apoptosis. Granzyme B is released from cytotoxic T lymphocytes and triggers apoptosis. Hydrogen peroxide is one of the activated oxygen species generated under conditions of cellular ischemia, producing nonspecific damage to cellular structures, particularly membranes.)

Question 36

36. A 71-year-old man diagnosed with pancreatic cancer is noted to have decreasing body mass index. His normal cells comprising skeletal muscle undergo atrophy by sequestering organelles and cytosol in a vacuole followed by fusion with a lysosome. However, the cancer continues to increase in size. Which of the following processes is most likely occurring in the normal cells but inhibited in the cancer cells of this man?

□ (A) Aging

□ (B) Apoptosis

□ (C) Autophagy

□ (D) Hyaline change

□ (E) Karyorrhexis

Answer 36

□ (C) Autophagy

(Autophagy is a form of cellular downsizing in response to stress, as the cell consumes itself, by upregulating Atgs genes. Lipofuscin granules are residual bodies left over from this process. There may be eventual cell death triggered by autophagy, but by a different mechanism than apoptosis, a form of single cell necrosis in which cell fragmentation occurs. Cancer cells acquire the ability to avoid autophagy, perhaps by downregulating PTEN gene expression, and maintain a survival advantage even as the patient is dying. There is slow autophagy with aging, but autophagy is accelerated with stressors such as malnutrition and chronic disease. Hyaline is a generic term for intracellular or extracellular protein accumulations appearing pink and homogenous with H&E staining. Karyorrhexis is nuclear fragmentation in a necrotic cell.)

Question 37

37. A 5-year-old child ingests 50 iron tablets, each with 27 mg of iron. Within 6 hours the child develops abdominal pain and lethargy. On physical examination he is hypotensive. Laboratory studies show metabolic acidosis. Through formation of which of the following compounds is the cell injury in this child most likely mediated?

□ (A) Ascorbic acid

□ (B) Hemosiderin

□ (C) Hydroxyl radical

□ (D) Nitric oxide

□ (E) Superoxide dismutase

Answer 37

□ (C) Hydroxyl radical

(Excessive iron ingestion, particularly in a child, can overwhelm the bodys ability to bind the absorbed free iron with the transport protein transferrin. The free iron contributes to generation of free radicals via the Fenton reaction. Ascorbic acid (vitamin C) and vitamin E both act as antioxidants to protect against free radical injury. Hemosiderin is a storage form of iron from excess local or systemic accumulation of ferritin, and by itself does not cause cell injury until large amounts are present, as with hemochromatosis. Nitric oxide generated within macrophages can be utilized to kill microbes. It can be converted to a highly reactive peroxynitrite anion. Superoxide dismutase helps break down superoxide anion to hydrogen peroxide, thus scavenging free radicals.)

Question 38

38. A proponent of Malbec, Syrah, and Merlot wines (all reds) touts their contribution to longevity, but this wine aficionado also controls the caloric content of his diet such that his body mass index is <22. This lifestyle promotes increased insulin sensitivity and glucose utilization. He fully expects to live long because he has read that caloric restriction prolongs life. In this man, which of the following proteins will most likely mediate the effect of calorie restriction upon increased longevity?

□ (A) Caspase

□ (B) Glutathione

□ (C) Sirtuin

□ (D) Telomerase

□ (E) Ubiquitin

Answer 38

□ (C) Sirtuin

(The one sure way to increase life span is calorie restriction. But why do without the things we like to do without them longer? Dietary excesses lead to increased morbidity with reduced quality of life, as well as mortality, from chronic diseases such as diabetes mellitus. The histone deacetylase activity of sirtuins may promote transcription of genes encoding for proteins that increase metabolic activity and inhibit effects of free radicals. Red wines have been shown to increase sirtuins, but dont drink too much! Moderation is the key. Glutathione promotes free radical breakdown, though chronic excessive alcohol consumption depletes hepatocyte glutathione. Caspases trigger apoptosis and cell death. Telomerases aid in promoting continued cell division, but cannot be altered by lifestyle, and turning them on is one feature of neoplasia. Ubiquitin is a peptide that is part of the ubiquitin-proteasome pathway of protein degradation seen with nutrient deficiencies, so when you eat less, be sure to eat a balanced diet.)