Weekly Pathology Exam - September 11, 2026 (Section A: MCQs)

Question 1

A 62-year-old woman with Idiopathic Pulmonary Fibrosis (IPF) has worsening dyspnea over 2 weeks without infection. HRCT now shows new bilateral ground-glass opacities superimposed on her existing fibrosis. What is the most likely complication?

Accepted Answer

Acute exacerbation of IPF — New ground-glass opacities in a patient with IPF, especially with worsening dyspnea and no clear infectious cause, are highly suggestive of an acute exacerbation of IPF. Pulmonary embolism can occur but is less likely to present with diffuse ground-glass opacities. Pneumothorax and bacterial pneumonia would typically have different HRCT findings or clinical clues.

Question 2

Pulmonary function testing in a patient with Idiopathic Pulmonary Fibrosis (IPF) is most likely to show which pattern?

Accepted Answer

Restrictive pattern with decreased TLC, FVC, and normal or increased FEV1/FVC ratio — IPF is a fibrotic interstitial lung disease, characterized by a restrictive pattern on pulmonary function tests. This means lung volumes (Total Lung Capacity - TLC, Forced Vital Capacity - FVC) are reduced, while the ratio of Forced Expiratory Volume in 1 second (FEV1) to FVC is typically normal or even increased.

Question 3

Which immunohistochemical marker is most useful in distinguishing malignant mesothelioma from metastatic adenocarcinoma to the pleura?

Accepted Answer

Calretinin — Calretinin is a marker that is typically positive in malignant mesothelioma and negative in metastatic adenocarcinoma. CK7 and TTF-1 are often positive in lung adenocarcinomas. CEA can be positive in both.

Question 4

A 55-year-old man with heart failure has a right-sided pleural effusion. Thoracentesis shows fluid protein of 2.1 g/dL, serum protein 7.0 g/dL, fluid LDH 88 U/L, and serum LDH 300 U/L. What is the most likely type of effusion?

Accepted Answer

Transudative — Using Light's criteria: Fluid protein/serum protein ratio = 2.1/7.0 = 0.3 (less than 0.5 suggests transudate). Fluid LDH/serum LDH ratio = 88/300 = 0.29 (less than 0.6 suggests transudate). Fluid LDH is also less than 2/3 of the upper limit of normal. Therefore, this is a transudative effusion, commonly seen in heart failure.

Question 5

A 48-year-old woman with breast cancer develops a right pleural effusion. Thoracentesis yields fluid protein of 5.2 g/dL, serum protein 6.8 g/dL, fluid LDH 420 U/L, and serum LDH 310 U/L. Cytology shows malignant cells. What is the most likely type of effusion?

Accepted Answer

Exudative — Using Light's criteria: Fluid protein/serum protein ratio = 5.2/6.8 = 0.76 (greater than 0.5 suggests exudate). Fluid LDH/serum LDH ratio = 420/310 = 1.35 (greater than 0.6 suggests exudate). Fluid LDH is also significantly elevated. The presence of malignant cells further supports an exudative effusion, specifically a malignant effusion.

Question 6

A 35-year-old man undergoes thoracic duct injury during left-sided neck dissection surgery. Two days later he develops a left pleural effusion. Thoracentesis yields milky white fluid with triglycerides of 210 mg/dL. What is the most likely diagnosis?

Accepted Answer

Chylothorax — A milky white pleural effusion with elevated triglyceride levels is characteristic of chylothorax, which occurs due to leakage of lymphatic fluid from the thoracic duct. Thoracic duct injury is a known cause.

Question 7

A 45-year-old man has a 3-month history of recurrent sinusitis, epistaxis, haemoptysis, and haematuria. CXR shows bilateral cavitating nodules. Urinalysis shows red cell casts. c-ANCA (PR3-ANCA) is strongly positive. What is the most likely diagnosis?

Accepted Answer

Granulomatosis with polyangiitis (Wegener's) — This clinical presentation (sinusitis, hemoptysis, hematuria, cavitating nodules) and the strongly positive c-ANCA (PR3-ANCA) are classic for Granulomatosis with Polyangiitis (formerly Wegener's granulomatosis). Goodpasture syndrome involves anti-GBM antibodies and typically lung and kidney involvement without upper airway symptoms. Microscopic polyangiitis is p-ANCA positive and usually lacks granulomas. EGPA has prominent eosinophilia.

Question 8

A 38-year-old woman with asthma develops peripheral blood eosinophilia of 18%, p-ANCA positivity, and a new mononeuritis multiplex. CXR shows transient pulmonary infiltrates. What is the most likely diagnosis?

Accepted Answer

Eosinophilic granulomatosis with polyangiitis (Churg-Strauss) — The combination of asthma, eosinophilia, p-ANCA positivity, mononeuritis multiplex, and transient pulmonary infiltrates is highly suggestive of Eosinophilic Granulomatosis with Polyangiitis (EGPA), also known as Churg-Strauss syndrome.

Question 9

A 24-year-old male smoker presents with haemoptysis and progressive dyspnea. Urinalysis shows proteinuria and red cell casts. CXR reveals bilateral alveolar infiltrates. Anti-GBM antibodies are strongly positive. Renal biopsy shows linear IgG deposits along the glomerular basement membrane. What is the most likely diagnosis?

Accepted Answer

Goodpasture syndrome — This patient's presentation of hemoptysis, dyspnea, renal abnormalities (proteinuria, red cell casts), and positive anti-GBM antibodies with linear IgG deposits on biopsy is pathognomonic for Goodpasture syndrome. This autoimmune disease targets both the pulmonary and glomerular basement membranes.

Question 10

A 55-year-old granite quarry worker has 20 years of exposure to silica dust. He now has progressive dyspnea and a dry cough. CXR shows upper lobe predominant nodules with eggshell calcification of hilar lymph nodes. Pulmonary function shows a restrictive pattern. What is the most likely diagnosis?

Accepted Answer

Silicosis — Silica dust exposure in a granite quarry worker, with the characteristic findings of upper lobe predominant nodules and eggshell calcification of hilar lymph nodes on CXR, along with a restrictive pattern on PFTs, is diagnostic of silicosis.

Question 11

A 32-year-old woman with no cardiopulmonary disease has progressive exertional dyspnea, syncope on exertion, and loud P2 on auscultation. Right heart catheterization shows mean pulmonary artery pressure of 38 mmHg with normal pulmonary capillary wedge pressure. What is the most likely diagnosis?

Accepted Answer

Pulmonary arterial hypertension (PAH) — The combination of exertional dyspnea, syncope, a loud P2, elevated mean pulmonary artery pressure (38 mmHg), and a normal pulmonary capillary wedge pressure points strongly towards pulmonary arterial hypertension (PAH). The normal PCWP rules out significant left heart failure as the cause of the pulmonary hypertension.

Question 12

A 70-year-old man with severe COPD has increasing drowsiness. ABG shows pH 7.28, PaO2 55 mmHg, PaCO2 72 mmHg, and HCO3 32 mEq/L. What is the most likely type of respiratory failure?

Accepted Answer

Type II (Hypercapnic) — This ABG shows both hypoxemia (PaO2 55 mmHg) and hypercapnia (PaCO2 72 mmHg) with a compensated metabolic alkalosis (HCO3 32 mEq/L). While hypercapnia is present, the severe hypoxemia is the most life-threatening abnormality driving the clinical picture and leading to drowsiness. This combination defines Type II respiratory failure, which can also have hypoxemic components in severe cases of COPD.

Question 13

A 63-year-old woman has sudden 'knife-like' chest pain radiating to the back, poorly controlled hypertension, and a widened mediastinum on CXR. CK is normal. What is the most likely diagnosis?

Accepted Answer

Aortic dissection — Sudden, severe chest pain radiating to the back, poorly controlled hypertension, and a widened mediastinum on CXR are classic signs of aortic dissection. Normal CK rules out myocardial infarction as the primary event.

Question 14

A man is examined 4 days after a large transmural anterolateral MI with cardiogenic shock. What is the most likely microscopic finding in the affected myocardium?

Accepted Answer

Coagulative necrosis with early granulation tissue formation — At 4 days post-MI, the microscopic picture is characterized by extensive coagulative necrosis of the myocardium. Early signs of healing, such as the influx of inflammatory cells and the beginnings of granulation tissue formation at the borders, would also be present. Enzymatic degradation is more prominent in the first 24-48 hours. Neutrophilic infiltration peaks around day 3-7.

Question 15

A 45-year-old woman has orthopnea, dysphagia, and a prior stroke. CXR shows near-normal LV but prominent left atrial border. What is the most likely condition?

Accepted Answer

Mitral stenosis — Orthopnea and a prominent left atrial border on CXR, especially in a patient with a history of stroke (which can increase risk of cardiac issues) and dysphagia (sometimes associated with left atrial enlargement), strongly suggest mitral stenosis. The enlarged left atrium is a hallmark of this condition due to backing up of blood from the left ventricle.

Question 16

A 16-year-old is stabbed in the left chest. BP barely obtainable, lungs clear, heart sounds barely audible. What is the most useful treatment?

Accepted Answer

Tube thoracostomy (chest tube insertion) — These signs (hypotension, muffled heart sounds, clear lungs on the stabbed side) are highly suggestive of cardiac tamponade secondary to hemopericardium. Tube thoracostomy is essential to drain the blood from the chest cavity, relieve pressure on the heart, and identify any ongoing bleeding. Needle decompression is for tension pneumothorax. Pericardial window is a surgical procedure to drain pericardial fluid.

Question 17

A 19-year-old with a mid-systolic click, mitral insufficiency, aortic root dilation, and a dislocated lens dies suddenly. Ruptured chordae found at autopsy. What is the most likely gene mutation?

Accepted Answer

FBN1 — The constellation of findings—aortic root dilation, mitral valve prolapse (implied by click and insufficiency, leading to chordal rupture), and a dislocated lens—is characteristic of Marfan syndrome. Marfan syndrome is caused by mutations in the FBN1 gene, which encodes fibrillin-1.

Question 18

A 72-year-old woman with no prior illness has three syncopal episodes then pulmonary edema. CXR shows LV prominence only. Cholesterol normal. What is the most likely diagnosis?

Accepted Answer

Aortic stenosis — Severe aortic stenosis can present with syncope (due to inadequate cerebral perfusion during exertion), pulmonary edema (due to increased afterload on the left ventricle), and prominent LV on CXR. The normal cholesterol makes hyperlipidemia less likely as a primary cause of coronary disease leading to these symptoms. Mitral regurgitation can cause pulmonary edema but syncope is less typical as the primary presentation.

Question 19

A 17-year-old short girl with absent puberty, webbed neck, upper extremity hypertension, diminished lower extremity pulses, and rib notching on CXR. What is the most likely cardiovascular abnormality?

Accepted Answer

Coarctation of the aorta — This collection of findings—short stature, absent puberty (often associated with chromosomal abnormalities that can co-occur with cardiovascular defects), webbed neck, hypertension in the upper extremities with diminished pulses in the lower extremities, and rib notching on CXR (due to collateral circulation)—is classic for Turner syndrome with coarctation of the aorta.

Question 20

A 65-year-old man with 20 years of uncontrolled diabetes has sudden severe abdominal pain, diminished lower-extremity pulses, and a pulsatile abdominal mass. CK normal. What is the most likely condition?

Accepted Answer

Abdominal aortic aneurysm rupture — A pulsatile abdominal mass, severe abdominal pain, and diminished lower extremity pulses in a patient with risk factors like diabetes and hypertension are highly suggestive of a ruptured abdominal aortic aneurysm (AAA). The diminished pulses are due to compromise of flow distally.

Question 21

A 49-year-old woman with poorly controlled atrial fibrillation dies after a stroke. Autopsy shows fused mitral leaflets, shortened chordae, and thrombus-filled enlarged left atrium. What is the most likely underlying cause?

Accepted Answer

Rheumatic heart disease — Fused mitral leaflets and shortened chordae are characteristic pathological findings of rheumatic heart disease, a sequela of recurrent streptococcal infections. This can lead to significant mitral valve dysfunction, left atrial enlargement, thrombus formation, and an increased risk of embolic stroke, especially in the context of atrial fibrillation.

Question 22

A 23-year-old woman with a malar rash has a friction rub, a faint systolic murmur, small mitral vegetations on echo, and a very high anti-Smith antibody titer. What is the most likely diagnosis?

Accepted Answer

Systemic lupus erythematosus (SLE) with Libman-Sacks endocarditis — The combination of a malar rash, friction rub, valvular vegetations (mitral valve), and a high anti-Smith antibody titer is highly indicative of Systemic Lupus Erythematosus (SLE). Libman-Sacks endocarditis refers to non-bacterial thrombotic endocarditis seen in SLE.

Question 23

A fetus at 18 weeks has a VSD, overriding aorta, and marked pulmonic atresia. If liveborn, what physical finding would most likely result?

Accepted Answer

Cyanosis — This combination of defects (VSD, overriding aorta, pulmonic atresia) describes a form of Tetralogy of Fallot with atresia. With marked pulmonic atresia, there is no antegrade flow to the lungs. Blood will preferentially shunt from the right ventricle (if present and functional) or directly from the right atrium to the aorta via the VSD and overriding aorta, bypassing the lungs. This results in severe cyanosis due to lack of oxygenation.

Question 24

A 50-year-old man has 3 hours of substernal chest pain, ST elevation in V1–V6, and pulmonary edema. Which lab finding is most likely?

Accepted Answer

Elevated Troponin I — Substernal chest pain with ST elevation in anterior leads (V1-V6) indicates an acute anterior ST-elevation myocardial infarction (STEMI). Myocardial damage leads to the release of intracellular proteins, with troponin being the most sensitive and specific marker for myocardial injury. Pulmonary edema indicates heart failure secondary to the MI. BNP would be elevated due to heart failure, and ejection fraction would be decreased, but elevated troponin is the most direct and immediate lab finding confirming myocardial infarction.

Question 25

A 52-year-old woman undergoes thyroidectomy for a well-circumscribed, encapsulated thyroid nodule. History shows uniform follicles resembling normal thyroid architecture. Which of the following is the most accurate designation?

Accepted Answer

Follicular adenoma — A well-circumscribed, encapsulated nodule with uniform follicles resembling normal thyroid architecture, especially in the absence of capsular or vascular invasion, is characteristic of a benign follicular adenoma. Malignant follicular lesions (carcinomas) would show invasion.

Question 26

A 65-year-old man presents with a firm mass in the sigmoid colon. Colonoscopy shows an ulcerated lesion with irregular borders. Biopsy demonstrates invasion through the muscularis propria. Which histological feature most strongly distinguishes this lesion as malignant rather than benign?

Accepted Answer

Invasion beyond the submucosa — Invasion beyond the submucosa (in this case, through the muscularis propria) is the definitive hallmark of malignancy. While epithelial dysplasia is a precancerous change, and goblet cells and mucinous secretion can be present in benign or malignant lesions, invasion is the key differentiator for malignancy.

Question 27

A 45-year-old woman develops chronic myeloid leukemia (CML). Cytogenetic analysis reveals a reciprocal translocation between chromosomes 9 and 22. The resultant fusion gene codes for a protein with which abnormal activity?

Accepted Answer

Constitutive tyrosine kinase activity — The t(9;22) translocation in CML creates the Philadelphia chromosome, which results in the BCR-ABL fusion gene. This gene product is a constitutively active tyrosine kinase, leading to uncontrolled proliferation of myeloid cells.

Question 28

A 33-year-old woman with breast cancer is found to have HER2/neu gene amplification. Which of the following best describes the mechanism by which HER2/neu promotes oncogenesis?

Accepted Answer

Stimulates cell proliferation and survival pathways — HER2/neu (ERBB2) is a receptor tyrosine kinase. Amplification of this gene leads to overexpression of the HER2 receptor, which then dimerizes and activates downstream signaling pathways (like PI3K/Akt and MAPK) that promote uncontrolled cell proliferation, survival, and resistance to apoptosis. While it can indirectly contribute to angiogenesis and metastasis, its primary oncogenic mechanism is through stimulating these growth and survival pathways.

Question 29

A 28-year-old man presents with bilateral retinoblastomas. Genetic analysis reveals a germline mutation in one allele of the RB gene, followed by somatic loss of the second allele. This exemplifies which principle?

Accepted Answer

Two-hit hypothesis — The development of retinoblastoma in this scenario is a classic example of the 'two-hit hypothesis' proposed by Knudson. This hypothesis states that for hereditary tumors, a germline mutation in one allele of a tumor suppressor gene (like RB1) is inherited, and a second somatic mutation in the remaining functional allele is required for tumor development. Both 'hits' are necessary.

Question 30

A 62-year-old man with chronic hepatitis B develops hepatocellular carcinoma. Molecular studies reveal inactivation of p53. Which of the following best describes the normal role of p53 in preventing tumor development?

Accepted Answer

Initiates DNA repair or induces apoptosis — The p53 protein is a crucial tumor suppressor. It acts as a 'guardian of the genome' by sensing DNA damage and cellular stress. In response, p53 can either initiate DNA repair mechanisms or, if the damage is too severe, trigger programmed cell death (apoptosis) to eliminate potentially cancerous cells. Inactivation of p53 allows cells with damaged DNA to survive and proliferate, leading to tumor development.

Question 31

A point mutation in the RAS gene that locks it in an active GTP-bound state results in which cellular effect?

Accepted Answer

Activation of downstream signaling pathways promoting growth and survival — RAS proteins are molecular switches that cycle between an inactive GDP-bound state and an active GTP-bound state. When mutated to be constitutively active (locked in the GTP-bound state), they continuously signal downstream pathways, primarily the MAPK pathway, which promotes uncontrolled cell proliferation, survival, and differentiation.

Question 32

The ERBB2 (HER2/neu) oncogene contributes to tumorigenesis primarily by:

Accepted Answer

Encoding a receptor tyrosine kinase that promotes cell growth and survival — As mentioned before, ERBB2 (HER2/neu) encodes a receptor tyrosine kinase. Its overexpression due to gene amplification leads to constitutive activation of signaling pathways that drive cell proliferation and survival, thus promoting tumorigenesis.

Question 33

Autocrine stimulation of growth factor receptors is best exemplified by:

Accepted Answer

A tumor cell secreting a growth factor that binds to receptors on its own surface — Autocrine signaling occurs when a cell produces a signaling molecule (like a growth factor) that acts on receptors on its own surface. This leads to self-stimulation of growth and survival.

Question 34

Mutation of the RB1 gene promotes cancer development by:

Accepted Answer

Inactivating the cell cycle checkpoint at the G1/S transition — The RB1 gene encodes the retinoblastoma protein (pRB), which is a critical regulator of the cell cycle. pRB normally binds to E2F transcription factors, preventing them from activating genes required for DNA synthesis and progression into the S phase. Mutation or inactivation of RB1 removes this brake, allowing uncontrolled cell cycle progression from G1 to S phase, thus promoting cancer.

Question 35

Loss of function of the TGF-β signaling pathway contributes to tumorigenesis by:

Accepted Answer

Increasing angiogenesis and promoting epithelial-mesenchymal transition — Transforming Growth Factor-beta (TGF-β) signaling has a dual role. In normal cells and early stages of some cancers, it acts as a tumor suppressor by inhibiting proliferation and inducing apoptosis. However, in more advanced cancers, cells can become resistant to TGF-β's growth inhibitory effects, while still responding to its pro-angiogenic and pro-metastatic effects (epithelial-mesenchymal transition - EMT). Thus, loss of TGF-β's tumor suppressor function, while retaining or gaining pro-tumorigenic functions, contributes to progression.

Question 36

The anti-apoptotic effect of BCL-2 overexpression in follicular lymphoma occurs due to:

Accepted Answer

Inhibition of mitochondrial outer membrane permeabilization — BCL-2 is an anti-apoptotic protein. Overexpression of BCL-2 prevents the release of pro-apoptotic factors, such as cytochrome c, from the mitochondria by inhibiting the permeabilization of the outer mitochondrial membrane. This blocks the activation of caspases, thereby inhibiting apoptosis and promoting tumor cell survival. Cyt c is released from the mitochondria, not the nucleus.

Question 37

The genetic defect associated with Fabry's disease is most likely carried on

Accepted Answer

Chromosome X — Fabry's disease is an X-linked recessive lysosomal storage disorder caused by mutations in the GLA gene, which is located on the X chromosome. This explains why it primarily affects males.

Question 38

Amount of dietary iodine in the control of thyroid hormone secretion

Accepted Answer

Iodine is a component of T3 and T4 — Iodine is an essential component of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). Without adequate iodine, the thyroid gland cannot synthesize sufficient amounts of these hormones, leading to hypothyroidism. While iodine intake does influence TSH secretion (e.g., Wolff-Chaikoff effect with high intake, or increased TSH with low intake to try to compensate), its direct role as a building block for thyroid hormones is fundamental to secretion.

Question 39

Movement of Cl- ion from gastric cells into the gastric cavity

Accepted Answer

Is an active transport process requiring ATP — The secretion of hydrochloric acid into the gastric lumen is an active process. The H+/K+ ATPase pump actively secretes H+ ions into the lumen, and Cl- ions are transported into the lumen via chloride channels, driven by the electrochemical gradient. This process is energy-dependent, requiring ATP.

Question 40

Myeloid cells in innate and adaptive immunity EXCLUDE the following:

Accepted Answer

T lymphocytes — Myeloid cells are derived from myeloid progenitor cells and are part of the innate immune system (e.g., neutrophils, macrophages, dendritic cells). T lymphocytes, on the other hand, are derived from lymphoid progenitor cells and are a key component of the adaptive immune system.

Question 41

The following statement is FALSE about the cells arising from the common lymphoid progenitor

Accepted Answer

They are primarily involved in the immediate inflammatory response. — Cells arising from the common lymphoid progenitor (B cells, T cells, NK cells) are primarily responsible for the adaptive immune response and possess antigen-specific receptors. The immediate inflammatory response is largely mediated by innate immune cells, including myeloid cells. While NK cells are lymphoid and part of innate immunity, their primary role is not immediate inflammation in the same way as neutrophils or macrophages.

Question 42

While complete aerobic oxidation of one mole of glucose in the cell yields 38 moles of ATP, complete catabolism of one mole of a 6-carbon atom fatty acid through the citric acid cycle yields

Accepted Answer

Approximately 46 moles of ATP — The complete oxidation of a saturated 6-carbon fatty acid (like hexanoic acid) involves beta-oxidation and subsequent entry into the citric acid cycle. A 6-carbon fatty acid undergoes 2 rounds of beta-oxidation, producing 2 acetyl-CoA molecules. Each acetyl-CoA yields about 10 ATP (via the citric acid cycle and oxidative phosphorylation). The beta-oxidation process itself yields a net of 1 FADH2 and 1 NADH per acetyl-CoA produced. For a 6-carbon fatty acid (3 acetyl-CoA units), it yields 3 NADH, 2 FADH2, and 3 acetyl-CoA. 3 acetyl-CoA yield 30 ATP. 3 NADH yield 7.5 ATP (assuming 2.5 ATP/NADH). 2 FADH2 yield 3 ATP (assuming 1.5 ATP/FADH2). Total approximately 40.5 ATP. However, the exact numbers vary based on shuttle systems. For a 6-carbon fatty acid, this is approximately 40-46 ATP.

Question 43

Immune privileged sites include the following EXCEPT:

Accepted Answer

Lungs — Immune privileged sites are areas of the body that are relatively protected from the immune system to prevent damage to vital organs and tissues. These typically include the brain, eyes, testes, and the anterior chamber of the eye. The lungs, while having specialized immune cells and mechanisms, are not generally considered immune privileged in the same way.

Question 44

The human genome

Accepted Answer

Consists of approximately 3 billion base pairs. — The human genome is estimated to contain approximately 3 billion base pairs. It has around 20,000-25,000 protein-coding genes, not 100,000. The genome contains both exons and introns. While largely identical, variations can occur due to somatic mutations (e.g., in cancer cells) or epigenetic modifications.

Question 45

The following are characteristics of skeletal muscle fibres EXCEPT:

Accepted Answer

Capable of spontaneous contraction — Skeletal muscle fibers are multinucleated, striated, and under voluntary control. However, they are not capable of spontaneous contraction; they require neural stimulation to contract.

Question 46

Increasing the frequency of stimulation so that a muscle contracts without relaxation is called

Accepted Answer

Tetanus — Tetanus is the sustained contraction of a muscle fiber that occurs when the frequency of stimulation is high enough that individual muscle twitches fuse together, resulting in a smooth, maximal contraction without any relaxation phase.

Question 47

Which type of sensation is most affected if the lesion is in the sensory cortex?

Accepted Answer

Proprioception and fine touch — The primary somatosensory cortex (postcentral gyrus) is responsible for processing highly localized sensations, particularly proprioception (body position sense) and fine touch (discriminative touch). While it receives input for pain and temperature, these pathways also involve other brainstem and thalamic structures. Crude touch and visceral sensations are processed in less localized areas.

Question 48

There are several important differences between a chemical and an electrical synapse. Which of the following statements does NOT constitute a a difference between these two types of synapses?

Accepted Answer

Chemical synapses are more common in the central nervous system than electrical synapses. — Electrical synapses, characterized by direct ion flow through gap junctions, are typically faster and can transmit signals bidirectionally. Chemical synapses, involving neurotransmitter release, are slower and unidirectionally transmit signals. While both types of synapses are found in the CNS, chemical synapses are far more abundant and play a more prominent role in complex neural processing within the CNS.

Question 49

Glucosuria is usually present without ketonuria

Accepted Answer

In type 2 diabetes mellitus — In type 2 diabetes mellitus, insulin resistance is the primary issue, and the pancreas can still produce some insulin. This usually prevents significant ketogenesis, so glucosuria occurs without ketonuria. In type 1 diabetes, starvation, and uncontrolled diabetes, the lack of insulin leads to increased lipolysis and ketone production, resulting in ketonuria alongside glucosuria.

Question 50

Which of the following substances is LEAST likely to inhibit glycolysis?

Accepted Answer

Maleinimide — Maleinimide is a reagent that reacts with sulfhydryl groups. While it can affect enzymes, it's not a classic inhibitor of glycolysis. Monoiodine acetate and sodium fluoride are well-known inhibitors of specific glycolytic enzymes (iodoacetate inhibits glyceraldehyde-3-phosphate dehydrogenase, and fluoride inhibits enolase). Cresol can also have inhibitory effects on cellular processes.

Weekly Pathology Exam - September 11, 2026 (Section A: MCQs)

Questions, Answers & Explanations