Innate Immunity: Practice questions

The triggering of the intrinsic pathway of apoptosis involves a balance between pro-apoptotic and anti-apoptotic proteins. Which of the following is anti-apoptotic?

Bcl-2. Feedback: Bax is a protein of the Bcl-2 family. This family of proteins all have a role in the apoptosis pathway. Some are pro-apoptotic and some anti-apoptotic and the balance between them determines whether or not apoptosis is activated via the intrinsic pathway. Bax and Bad are pro-apoptotic proteins. The protein which names the family, Bcl-2, is anti-apoptotic. The key event which triggers the start of the intrinsic pathway of apoptosis is the release of cytochrome c from the mitochondrion. Cytochrome c is therefore pro-apoptotic.

The passage of a cell through the stages of the cell cycle is controlled by protein kinases that phosphorylate many different proteins at appropriate times. What are these protein kinases called?

Cyclin-dependent kinases

Damaged cells die by apoptosis. True or False?

F Though cells with damaged DNA are killed by apoptosis if the damage cannot be repaired, most forms of damage, such as physical damage, and damage produced by oxygen deprivation produce necrosis. Here, membranes are ruptured and cell contents leak out causing inflammation in the surrounding tissue. Necrotic cell death is an accidental, not a regulated, process.

Appropriate cyclin dependent kinases are synthesized at the start of each phase of the cell cycle and destroyed before the cell proceeds to the next phase: true or false? `

F Cyclin dependent kinase (Cdk) levels remain relatively constant throughout the cell cycle, but their activity varies. They are inactive unless they are activated by binding the appropriate cyclin. Levels of cyclins change rapidly throughout the cell cycle. Appropriate cyclins are synthesized at the start of each phase of the cycle and destroyed before the cell moves to the next phase. This ensures that Cdks are only active at the appropriate time.

Each cyclin dependent kinase (Cdk) is activated by a specific cyclin and works at one specific checkpoint in the cell cycle. True or false? `

F Some Cdks are activated by different cyclins in different phases of the cell cycle. They can work at different checkpoints, depending which cyclin is binding to them. As well as activating the Cdk the cyclin can determine the substrate it phosphorylates, thus directing it to a different target. The cyclins, not the Cdks, are the main determinants of specificity.

Which of the following proteins is a death receptor which triggers the extrinsic pathway of apoptosis? `

Fas

Which of the following occurs in meiosis but not in mitosis?

b) Pairing of homologous chromosomes at the metaphase plate.

Which tissue is the most susceptible to liquefactive necrosis following ischemic injury? Pancreas Liver Spleen Brain Intestine

brain

In which of the following situations would cells die by necrosis, not apoptosis?

c) Removal of heart muscle cells damaged by oxygen depletion following cardiac infarction.

Cyclin dependent kinases which control progression through cell cycle checkpoints are fully activated by which of the following:

c) binding to cyclin, plus phosphorylation by a Cdk activating protein kinase.

Which cellular organelles are involved in the initiation of the intrinsic pathway of apoptosis?

c) mitochondria The initiating procaspases of the intrinsic apoptosis pathway are attached to the outer membrane of the mitochondria. They are released when the intrinsic pathway is initiated, forming a multimolecular cluster called the apoptosome in which the clustered procaspases can self activate. Thus the mitochondria are the organelles involved in the initiation of internally stimulated apoptosis. In some circumstances incorrectly folded proteins that accumulate in the endoplasmic reticulum can be transported to the cytoplasm where they trigger apoptosis directly. However, this is an unusual mode of initiation which occurs rarely. `

A cellular mutation results in transcription with translation of a protein that does not fold properly. The misfolded protein remains within the cell and is not excreted. Activation of which of the following cytoplasmic enzymes is most likely to occur? A Caspase B Glutathione peroxidase C NADPH oxidase D Ribonuclease E Telomerase

caspase

75-year-old woman has a complaint of shortness of breath and chest pain that radiates to the left shoulder. Serum levels of CK-MB (myocardial creatine kinase) and cardiac muscle troponin I (cTnI) are elevated. Which of the following types of myocardial cell death would best account for these findings? Apoptosis Caseous necrosis Coagulative necrosis Fat necrosis Liquefactive necrosis

coagulative necrosis

A 10-year-old black man with a known history of sickle cell disease presents to the emergency department complaining of left upper quadrant pain suggestive of a splenic infarct. Microscopic examination of the spleen would most likely reveal Caseous necrosis Coagulative necrosis Fibrinoid necrosis Gangrenous necrosis Liquefactive necrosis

coagulative necrosis

A 65 year old man presents with angina and dyspnea. He has a family history of hypercholesterolemia. Unfortunately despite thrombolytic therapy he dies. What would you expect to see on light microscopic examination of cardiac tissue? Caseous necrosis Enzymatic fat necrosis Liquefactive necrosis Coagulative necrosis

coagulative necrosis

A well-demarcated lesion with increased cytoplasmic eosinophilia, karyolysis, and intact tissue architecture is characteristic of Caseous necrosis Enzymatic fat necrosis Coagulative necrosis Cloudy swelling Liquefactive necrosis

coagulative necrosis

A 26-year-old man has had a high fever for the past 2 days. On exam he has a heart murmur. Echocardiography shows destruction of the aortic valve by large, irregular vegetations. Staphylococcus aureus is cultured from his blood. He develops left upper quadrant pain. Abdominal CT shows a wedge-shaped 1.5 x 3 cm splenic lesion with base on the capsule. The splenic lesion is most likely to result from which of the following cellular abnormalities? A Coagulative necrosis B Abscess formation C Metaplasia D Caseous necrosis E Liquefactive necrosis

coagulative necrosis: vascular occlusion followed by embolism from vegetations of infective endocarditis

In order to enter the cell cycle a cell must be stimulated from outside. What type of molecule provides this stimulation? a) Cyclins b) Cyclin-dependent kinases c) Cytokines and growth factors d) Tyrosine kinases

cytokines and growth factors

A pathologist notes the following findings after light microscopic examination of a section of liver from a chronic alcoholic. Which of the following is an example of a reversible injury? A. Pyknosis B. Cytoplasmic vacuoles C. Rupture of cell membrane D. Karyolysis E. Karyorrhexis

cytoplasmic vesicles

At the end of each phase of the cell cycle cyclins activating Cdks in that phase are inactivated irreversibly by which of the following mechanisms?

d) Destruction by proteolysis in a proteasome.

Which of the following are killed by the extrinsic apoptosis pathway? `

d) Virus infected cells.

A patient is admitted with severe substernal chest pain of 4 hours duration. Lab tests reveal increased level of the serum creatine kinase. This is most likely due to: Mitochondrial swelling Nuclear lysis Damage of plasma membranes Increased endoplasmic reticulum Increased golgi activity

damage of plasma membranes

A 21-year-old woman has a routine Pap smear performed for a health screening examination. The pathology report indicates that some cells are found cytologically to have larger, more irregular nuclei. A follow-up cervical biopsy microscopically demonstrates disordered maturation of the squamous epithelium, with hyperchromatic and pleomorphic nuclei extending nearly the full thickness of the epithelial surface. No inflammatory cells are present. Which of the following descriptive terms is best applied to these Pap smear and biopsy findings? A Dysplasia B Metaplasia C Anaplasia D Hyperplasia E Aplasia

dysplasia (precursor to neoplasia also is considered a disordered development of tissue)

A 38-year-old man has a health screening examination. He has a routine chest x-ray that shows a 2 cm nodule in the right lower lobe. The nodule has focal calcifications. A wedge resection of the nodule is done. On microscopic examination the nodule shows caseous necrosis and calcification. Which of the following processes explains the appearance of the calcium deposition: A Dystrophic calcification B Apoptosis C Hypercalcemia D Metastatic calcification E Excessive ingestion of calcium

dystrophic calcification (alcium is deposited in and around the granuloma as a reaction to injury with necrosis. Most pulmonary granulomas are the result of infection, typically tuberculosis.)

Laproscopic examination of the abdomen was performed on a 50 year old chronic alcoholic man. The surgeon noted digestion of tissue with soap formation and calcification. Which of the following is this most likely characteristic of? Coagulative necrosis Caseous necrosis Enzymatic fat necrosis Liquefactive necrosi

enzymatic fat necrosis

A 40-year-old woman has the sudden onset of severe abdominal pain. On physical examination she has diffuse tenderness in all abdominal quadrants, with marked guarding and muscular rigidity. She has laboratory findings that include serum AST of 43 U/L, ALT of 30 U/L, LDH 630 U/L, and lipase 415 U/L. An abdominal CT scan reveals peritoneal fluid collections and decreased attenuation along with enlargement of the pancreas. Which of the following cellular changes is most likely to accompany these findings? A Coagulative necrosis B Dry gangrene C Fat necrosis D Apoptosis E Liquefactive necrosis

fat necrosis

A 53-year-old man suffers a cardiac arrest and his wife calls emergency services. The paramedics arrive a few minutes later and begin life support measures. A regular heart rate is established after 40 minutes of resuscitative efforts as he is being transported to the hospital. A thrombolytic agent (tPA) is administered. Which of the following cellular processes is most likely to occur in his myocardium following administration of the tPA? A Apoptosis B Free radical injury C Heterophagocytosis D Squamous metaplasia E Accumulation of cytokeratins`

free radical injury (ischemia followed by repercussion)

n an experiment, a tissue preparation is subjected to oxidant stress. There are increased numbers of free radicals generated within the cells. Generation of which of the following enzymes within these cells is the most likely protective mechanism to reduce the number of free radicals? A Glutathione peroxidase B Catalase C Hydrogen peroxide D NADPH oxidase E Myeloperoxidase

glutathione peroxidase

71-year-old man has difficulty with urination. His urinary retention leads to numerous trips to the restroom per day. On digital rectal examination is prostate is diffusely enlarged. Which of the following represents a pathologic change leading to this man's problem? A Dysplasia B Hypertrophy C Hyperplasia D Metaplasia E Neoplasia

hyperplasia

A 20-year-old woman had Goodpasture syndrome which progressed to chronic renal failure. She is 165 cm tall and weighs 55 kg. She now has blood pressure measurements in the range of 150/90 to 180/110 mm Hg, but does not regularly take medications. Laboratory studies show her blood urea nitrogen is over 100 mg/dL and she requires chronic dialysis. A chest x-ray shows an enlarged heart. The size of her heart is most likely to be the result of which of the following processes involving the myocardial fibers? A Hypertrophy B Fatty infiltration C Hyperplasia D Fatty degeneration E Edema

hypertrophy (pressure of systemic hypertension leads to myocardial fiber hypertrophy and an increased size in heart)

The lifestyle patterns of healthy persons from 20 to 30 years of age are studied. A subset of these persons have a lifestyle characterized by consumption of a lot of pizza and very little physical exercise. Which of the following tissue changes is most likely to develop in this subset of persons as a consequence of this lifestyle? A Fatty metamorphosis of liver B Pancreatic fat necrosis C Fatty degeneration of myocardium D Hypertrophy of steatocytes E Metaplasia of muscle to adipose tissue

hypertrophy of steatocytes

A 50-year-old woman with a history of unstable angina suffers an acute myocardial infarction. Thrombolytic therapy with tissue plasminogen activator (tPA) is administered to restore coronary blood flow. In spite of this therapy, the degree of myocardial fiber injury may increase because of which of the following cellular abnormalities? A Cytoskeletal intermediate filament loss B Decreased intracellular pH from anaerobic glycolysis C Increased free radical formation D Mitochondrial swelling E Nuclear chromatin clumping F Reduced protein synthesis

increased free radical formation (toxic free radicals released from neutrophils when blood flow is restored after ischemia)

You are asked to participate in a research project on myocardial infarctions in a rat model. Which of the following occurs in ischemic cell injury? Efflux of K+ and Na+ Influx of K+ and Ca++ Influx of K+ and H2O Influx of Na+ and Ca++ Influx of Na+ and K+

influx of Na and Ca2+

Coagulative necrosis usually results from Abscess formation Ischemia Trauma Tuberculosis Syphilis

ischemia

A patient suffers a stroke and has left sided weakness and paralysis in the upper extremity. The type of necrosis associated with a well-developed infarct of the brain is Coagulative Enzymatic fat Liquefactive Gangrenous

liquefactive

A 19-year-old woman gives birth to her first child. She begins breast feeding the infant. She continues breast feeding for almost a year with no difficulties and no complications. Which of the following cellular processes that began in the breast during pregnancy allowed her to nurse the infant for this period of time? A Stromal hypertrophy B Epithelial dysplasia C Steatocyte atrophy D Ductal epithelial metaplasia E Lobular hyperplasia

lobular hyperplasia (increase in breast lobules) (hyperplasia: increase in cell reproduction rate)

A 31-year-old woman has been previously diagnosed with systemic lupus erythematosus. She has had chest pain for the past 6 months. A chest radiograph shows bilateral pleural effusions. Thoracentesis on the right yields 400 mL of clear yellow serous fluid, and a cell count shows only a few cells present. What type of cell is most likely to be most numerous in this fluid? A Basophil B Ciliated columnar cell C Eosinophil D Fibroblast E Langhans giant cell F Lymphocyte G Neutrophil

lymphocytes (serous effusion, typical for autoimmune disease)

A 38-year-old man incurs a traumatic blow to his upper left arm. He continues to have pain and tenderness even after 3 months have passed. A plain film radiograph reveals a 4 cm circumscribed mass in the soft tissue adjacent to the humerus. The mass contains peripheral areas of brightness on the x-ray. Over the next year this mass gradually resolves. Which of the following terms best describes the changes described? A Dysplasia B Hyperplasia C Hypertrophy D Metaplasia E Neoplasia

metaplasia (calcification of tissues)

44-year-old woman has had congestive heart failure for the past 4 years. She develops a fever that persists for over a week. On physical examination, a heart murmur is present. Her temperature is 38.4°C. Laboratory studies show a blood culture positive for Streptococcus, viridans group. An echocardiogram reveals a 1 cm vegetation on the superior aspect of her mitral valve. Which of the following pathologic changes is most likely present in her mitral valve? A Passive congestion B Necrosis C Extensive edema D Granulomatous inflammation E Dystrophic calcification

necrosis

A 71-year-old woman had the loss of consciousness that persisted for over an hour. When she becomes arousable, she cannot speak nor move her right arm. A cerebral angiogram revealed an occlusion to her left middle cerebral artery. Months later, a computed tomographic (CT) scan shows a large 5 cm cystic area in her left parietal lobe cortex. This CT finding is most likely the consequence of resolution from which of the following cellular events? A Liquefactive necrosis B Atrophy C Coagulative necrosis D Caseous necrosis E Apoptosis

not coagulative: usually in kidney or spleen; not caseous necrosis: typical of TB, Answer: liquefactive necrosis (stroke with cerebral infarction and loss of brain tissue)

A 53-year-old man has experienced severe chest pain for the past 6 hours. On physical examination he is afebrile, but has tachycardia. Laboratory studies show a serum troponin I of 10 ng/mL. A coronary angiogram is performed emergently and reveals >90% occlusion of the anterior interventricular (left anterior descending) artery. In this setting, an irreversible injury to myocardial fibers will have occurred when which of the following cellular changes occurs? A Glycogen stores are depleted B Cytoplasmic sodium increases C Nuclei undergo karyorrhexis D Intracellular pH diminishes E Blebs form on cell membranes

nuclei undergo karyorrhexis

A study is performed involving the microscopic analysis of tissues obtained from surgical procedures. Some of these tissues have the microscopic appearance of an increased cell size of multiple cells within the tissue, due to an increase in the amount of cell cytoplasm, with nuclei remaining uniform in size. Which of the following conditions is most likely to have resulted in this finding? A Uterine myometrium in pregnancy B Female breast at puberty C Liver following partial resection D Ovary following menopause E Cervix with chronic inflammation

uterine myometrium in pregnancy (increase in cell size causes increase in size, however this returns back)

Caseous necrosis is characterized morphologically by Preservation of tissue outlines Basophilia Semi-liquid consistency Wedge-shaped periphery Amorphous appearance

amorphous appearance

The pattern of cell death that is characterized by conversion of a single cell to an acidophilic body, usually with loss of the nucleus but with preservation of its shape to permit recognition of cell boundaries is termed Apoptosis Caseous necrosis Fibrinoid necrosis Liquefactive necrosis

apoptosis

You are asked to write a microscopic description of the coagulative necrosis that was noted in the heart of a patient who died of a heart attack because of cocaine abuse. Which of the following best described coagulative necrosis? Eosinophilic cytoplasm with cell outlines preserved Granular, friable mass of material devoid of cell outlines Localized, solid, basophilic lesion with calcification Necrosis in which tissue is converted into a fluid

Eosinophilic cytoplasm with cell outlines preserved

A 48-year-old woman has a malignant lymphoma involving lymph nodes in the para-aortic region. She is treated with a chemotherapeutic agent which results in the loss of individual neoplastic cells through fragmentation of individual cell nuclei and cytoplasm. Over the next 2 months, the lymphoma decreases in size, as documented on abdominal CT scans. By which of the following mechanisms has her neoplasm primarily responded to therapy? A Coagulative necrosis B Mitochondrial poisoning C Phagocytosis D Acute inflammation E Apoptosis

Apoptosis, the drug effect is targeted at neoplastic/fast growing cells (not coagulative necrosis which is from ischemia)

A pathologist notes that a biopsy from the lung of living patients shows the morphologic changes indicative of irreversible injury and cell death. Which of the following is most likely responsible for cell death in a living body? Cytolysis Necrosis Putrefaction Autolysis Somatic death

autolysis

At which cell cycle checkpoint is the cell cycle halted if the cell's DNA is damaged?

G1 - S

Passage through which checkpoint is the step which commits the cell to proceed through to mitosis and cell division?

G1 to S.

In which phase of the cell cycle are the chromosomes inactive, condensed, and not transcribed to messenger RNA?

M phase.

The cell is not allowed to pass the cell cycle restriction point if DNA damage is detected. Which of the following proteins are involved in detection of DNA damage and inhibition of the cycle at the restriction point? Please select all that apply.

Replication protein A (RPA). b) ATM (ataxia telangiectasia mutated) protein. d) p53.

In which phase of the cell cycle is DNA replicated?

S phase