Weekly Pathology Exam - August 28, 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. Most likely complication?

Accepted Answer

Acute exacerbation of IPF — New ground-glass opacities in a patient with IPF, especially with worsening dyspnea without clear signs of infection, are highly suggestive of an acute exacerbation of IPF. Pulmonary embolism, pneumonia, and malignancy are less likely given the presentation.

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 FEV1, FVC, and TLC — IPF is a restrictive lung disease, characterized by reduced lung volumes, including FEV1 (Forced Expiratory Volume in 1 second), FVC (Forced Vital Capacity), and TLC (Total Lung Capacity), leading to a restrictive pattern on PFTs. The FEV1/FVC ratio is typically normal or increased.

Question 3

Which immunohistochemical marker distinguishes malignant mesothelioma from metastatic adenocarcinoma to the pleura?

Accepted Answer

Calretinin — Calretinin is a sensitive and specific marker for mesothelioma. CK7 and CEA are often positive in adenocarcinoma, and TTF-1 is typically positive in lung adenocarcinoma, making them less useful for distinguishing mesothelioma from metastatic adenocarcinoma.

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. Most likely type of effusion?

Accepted Answer

Transudative — This is a transudative effusion based on Light's criteria. The fluid protein is low (2.1 g/dL, which is <2.5 g/dL, and the pleural fluid/serum protein ratio is <0.5). The fluid LDH is also low (88 U/L, and the pleural fluid/serum LDH ratio is <0.6). Heart failure is a common cause of transudative effusions.

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. Most likely type of effusion?

Accepted Answer

Exudative — This is an exudative effusion. The fluid protein is high (5.2 g/dL, which is 3.5 g/dL, and the pleural fluid/serum protein ratio is 0.5). The fluid LDH is also high (420 U/L, and the pleural fluid/serum LDH ratio is 0.6). The presence of malignant cells confirms a malignant effusion, which is a type of exudate.

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. Most likely diagnosis?

Accepted Answer

Chylothorax — A milky white pleural effusion with elevated triglyceride levels (typically 110 mg/dL) is characteristic of chylothorax, which occurs due to leakage of lymphatic fluid from the thoracic duct.

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. Most likely diagnosis?

Accepted Answer

Granulomatosis with polyangiitis (formerly Wegener's) — This constellation of symptoms (sinusitis, haemoptysis, haematuria, cavitating nodules, red cell casts) and the positive c-ANCA (PR3-ANCA) are classic for Granulomatosis with Polyangiitis (GPA). Goodpasture syndrome typically involves anti-GBM antibodies and lung and kidney involvement without upper airway or sinusitis symptoms.

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. Most likely diagnosis?

Accepted Answer

Polyarteritis nodosa — Eosinophilic granulomatosis with polyangiitis (EGPA), also known as Churg-Strauss syndrome, is characterized by asthma, peripheral eosinophilia, p-ANCA positivity, and systemic vasculitis (which can manifest as mononeuritis multiplex and transient pulmonary infiltrates).

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. Most likely diagnosis?

Accepted Answer

Goodpasture syndrome — The combination of pulmonary hemorrhage (haemoptysis, alveolar infiltrates on CXR), glomerulonephritis (proteinuria, red cell casts), positive anti-GBM antibodies, and linear IgG deposits on renal biopsy is pathognomonic for Goodpasture syndrome.

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. Most likely diagnosis?

Accepted Answer

Silicosis — Occupational exposure to silica dust (granite quarry work), progressive dyspnea, upper lobe predominant nodular opacities, and eggshell calcification of hilar lymph nodes are characteristic features of silicosis. Asbestosis typically affects the lower lobes and shows pleural plaques and interstitial fibrosis. Coal worker's pneumoconiosis is associated with coal dust exposure and black pigment deposition.

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. Most likely diagnosis?

Accepted Answer

Pulmonary arterial hypertension (PAH) — Progressive exertional dyspnea, syncope on exertion, and a loud P2 are suggestive of pulmonary hypertension. The right heart catheterization findings of elevated mean pulmonary artery pressure (38 mmHg) with a normal pulmonary capillary wedge pressure (indicating no left heart failure) confirm pre-capillary pulmonary hypertension, most consistent with Pulmonary Arterial Hypertension (PAH).

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. Most likely type of respiratory failure?

Accepted Answer

Type II (hypercapnic) — The ABG shows both hypoxemia (PaO2 55 mmHg) and hypercapnia (PaCO2 72 mmHg) with respiratory acidosis (pH 7.28). However, the defining feature for Type II respiratory failure is the elevated PaCO2 leading to respiratory acidosis. While hypoxemia is present, it is a consequence of the impaired ventilation. The presence of significant hypercapnia and acidosis indicates Type II (hypercapnic) respiratory failure. The elevated HCO3 (32 mEq/L) indicates a chronic component with metabolic compensation.

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. Most likely diagnosis?

Accepted Answer

Aortic dissection — Sudden, severe, 'knife-like' chest pain radiating to the back, poorly controlled hypertension, and a widened mediastinum on CXR are classic signs of aortic dissection. Normal CK levels rule out myocardial infarction as the primary cause of chest pain.

Question 14

A man is examined 4 days after a large transmural anterolateral MI with cardiogenic shock. Most likely microscopic finding?

Accepted Answer

Extensive coagulative necrosis with early macrophage infiltration — Four days after a transmural myocardial infarction, the microscopic findings include extensive coagulative necrosis, early neutrophil infiltration which is beginning to be replaced by macrophages, and beginning of granulation tissue formation. Wavy fibers and early coagulation necrosis are more typical of the initial stages (hours).

Question 15

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

Accepted Answer

Mitral stenosis — Orthopnea and a prominent left atrial border on CXR in the setting of dysphagia and prior stroke suggest a significant left atrial abnormality, most commonly caused by mitral stenosis. Mitral stenosis leads to left atrial enlargement due to increased pressure and volume backup from the left atrium into the left ventricle. Dysphagia can be due to compression of the esophagus by an enlarged left atrium. Prior stroke may be related to atrial fibrillation and thromboembolism, often associated with mitral valve disease.

Question 16

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

Accepted Answer

Immediate thoracotomy — The presentation of barely obtainable blood pressure, clear lungs, and barely audible heart sounds after a chest stab wound is highly suggestive of cardiac tamponade. Needle decompression is for tension pneumothorax. Intravenous fluids may help but are insufficient alone. Immediate thoracotomy is an option for severe trauma but pericardial window is the definitive treatment for tamponade. However, in a situation of hemodynamic instability due to suspected tamponade, pericardiocentesis (which can be a temporizing measure before a surgical procedure like a window) or immediate thoracotomy for exploration and decompression are the most urgent considerations. Given the options, Pericardial window is the most direct intervention for tamponade, but immediate thoracotomy might be considered in such a critical situation for direct cardiac repair and tamponade relief.

Question 17

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

Accepted Answer

FBN1 — The constellation of findings (mid-systolic click, mitral insufficiency, aortic root dilation, dislocated lens, ruptured chordae) is highly suggestive of Marfan syndrome. Marfan syndrome is caused by mutations in the FBN1 gene, which encodes fibrillin-1, a component of connective tissue. COL3A1 mutations cause Ehlers-Danlos syndrome type IV. MYH11 mutations are associated with thoracic aortic aneurysms and dissections, but not typically the ocular or skeletal features of Marfan. MYOCD is not directly implicated in these findings.

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. Most likely diagnosis?

Accepted Answer

Aortic stenosis — Syncope, especially exertional, followed by pulmonary edema in an elderly patient with a prominent left ventricle on CXR is highly suggestive of severe aortic stenosis. The stenosis obstructs outflow from the left ventricle, leading to increased end-diastolic pressure, pulmonary congestion, and reduced cardiac output which can manifest as syncope. Normal cholesterol is noted, but this is not a contraindication to AS.

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. Most likely cardiovascular abnormality?

Accepted Answer

Coarctation of the aorta — The constellation of short stature, absent puberty, webbed neck, upper extremity hypertension, diminished lower extremity pulses, and rib notching on CXR is characteristic of Turner syndrome (45,X). The most common cardiovascular abnormality associated with Turner syndrome is coarctation of the aorta. The rib notching is a result of collateral flow to the lower body through enlarged intercostal arteries, bypassing the coarcted segment.

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. Most likely condition?

Accepted Answer

Ruptured abdominal aortic aneurysm (AAA) — A pulsatile abdominal mass, severe abdominal pain, and diminished lower extremity pulses in a patient with risk factors for atherosclerosis (uncontrolled diabetes) are highly suggestive of a ruptured abdominal aortic aneurysm. The aneurysm can compress or occlude the iliac arteries, leading to diminished pulses in the lower extremities. Normal CK rules out cardiac causes of pain.

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. Most likely underlying cause?

Accepted Answer

Rheumatic heart disease — Fused mitral leaflets, shortened chordae, an enlarged left atrium with thrombus, and a history of atrial fibrillation and stroke are characteristic findings of rheumatic heart disease, which is a sequela of rheumatic fever. This leads to progressive mitral valve damage.

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. Most likely diagnosis?

Accepted Answer

Systemic lupus erythematosus (SLE) — The combination of malar rash, friction rub (pericarditis), valvular vegetations (Libman-Sacks endocarditis, though described as small and mitral), and a very high anti-Smith antibody titer is highly indicative of Systemic Lupus Erythematosus (SLE). Anti-Smith antibodies are specific for 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 describes a form of Tetralogy of Fallot with pulmonary atresia. With significant pulmonary atresia, there is a severe reduction in pulmonary blood flow. Systemic blood flow is dependent on the overriding aorta receiving mixed venous blood. This leads to severe hypoxemia and cyanosis from birth.

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 creatinine kinase-MB (CK-MB) — The symptoms (chest pain, pulmonary edema) and ECG findings (ST elevation in V1-V6) are indicative of an acute anterior ST-elevation myocardial infarction (STEMI). The most sensitive and specific cardiac biomarker that would be elevated within 3 hours of symptom onset is troponin. However, CK-MB is also an indicator of myocardial injury and would be elevated. Normal troponin or decreased LDH would be inconsistent with MI. Low amylase is not directly related to MI.

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 thyroid nodule with uniform follicles resembling normal thyroid architecture, without capsular or vascular invasion, is characteristic of a benign follicular adenoma. Follicular carcinoma would show capsular or vascular invasion, and papillary or medullary carcinomas have distinct histological features.

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 of the submucosa — Invasion of the submucosa is a definitive feature of malignancy. While increased mitotic activity and nuclear pleomorphism are common in malignant cells, they can also be seen in some benign conditions. Formation of glandular structures is characteristic of adenocarcinoma, which can be benign or malignant, but 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 activation of tyrosine kinase activity — The translocation between chromosomes 9 and 22 creates the Philadelphia chromosome, resulting in the BCR-ABL fusion gene. This fusion gene encodes a constitutively active tyrosine kinase, which drives the uncontrolled proliferation of myeloid cells seen in CML.

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

It encodes a receptor tyrosine kinase that promotes cell proliferation and survival. — HER2/neu (also known as ERBB2) is a receptor tyrosine kinase. Gene amplification leads to overexpression of this receptor, which then dimerizes and activates downstream signaling pathways (like PI3K/Akt and MAPK) that promote uncontrolled cell proliferation, survival, and angiogenesis, thus contributing to oncogenesis.

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

The two-hit hypothesis (Knudson's hypothesis) — Knudson's two-hit hypothesis explains the development of hereditary cancers. It proposes that two independent 'hits' (mutations) are required for tumor development. In hereditary retinoblastoma, the first hit is a germline mutation in one RB allele, and the second hit is a somatic mutation in the remaining RB allele in retinal cells.

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

It induces apoptosis in damaged cells. — p53 is a tumor suppressor gene that acts as a 'guardian of the genome'. Its normal functions include inducing cell cycle arrest in response to DNA damage, promoting DNA repair, and initiating apoptosis (programmed cell death) if the damage is irreparable. Inactivation of p53 allows cells with damaged DNA to survive and proliferate, increasing the risk of cancer 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 that promote cell growth and survival — RAS proteins are small GTPases that act as molecular switches in signaling pathways. When bound to GTP, they are active and transmit signals downstream. Mutations that lock RAS in its active GTP-bound state lead to constitutive activation of downstream signaling pathways, such as the MAPK and PI3K/Akt pathways, promoting uncontrolled cell proliferation and survival.

Question 32

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

Accepted Answer

Encoding a receptor tyrosine kinase with constitutive activation. — ERBB2 (HER2/neu) is amplified in many cancers, leading to overexpression of its protein product, a receptor tyrosine kinase. This overexpression results in constitutive activation of downstream signaling pathways that promote cell proliferation, survival, and angiogenesis, driving tumorigenesis.

Question 33

Autocrine stimulation of growth factor receptors is best exemplified by:

Accepted Answer

A tumor cell releasing 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 binds to receptors on its own surface, stimulating its own growth and survival. Paracrine signaling involves binding to receptors on nearby cells.

Question 34

Mutation of the RB1 gene promotes cancer development by:

Accepted Answer

Allowing uncontrolled progression through the G1/S checkpoint. — The RB1 gene encodes the retinoblastoma protein (pRB), a critical tumor suppressor that regulates the cell cycle. pRB normally binds to E2F transcription factors, preventing them from activating genes required for DNA synthesis and cell cycle progression (G1/S transition). Loss of functional pRB due to RB1 mutation leads to uncontrolled activation of E2F and thus unregulated progression through the G1/S checkpoint.

Question 35

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

Accepted Answer

Removing a key inhibitory signal for cell proliferation. — The TGF-β signaling pathway typically acts as a tumor suppressor by inhibiting cell proliferation and promoting differentiation and apoptosis. Loss of function of this pathway removes these inhibitory signals, allowing for uncontrolled cell growth, a hallmark of cancer.

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 inhibits apoptosis by preventing the release of pro-apoptotic factors, such as cytochrome c, from the mitochondria into the cytoplasm. This process is crucial for the initiation of caspase cascades, which execute the apoptotic program. Therefore, BCL-2 overexpression blocks mitochondrial outer membrane permeabilization.

Question 37

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

Accepted Answer

X chromosome — Fabry disease is an X-linked recessive disorder caused by mutations in the GLA gene, which encodes the enzyme alpha-galactosidase A. This gene is located on the X chromosome.

Question 38

Amount of dietary iodine in the control of thyroid hormone secretion

Accepted Answer

Iodine is a substrate for thyroid hormone synthesis. — Iodine is an essential component of thyroid hormones (thyroxine (T4) and triiodothyronine (T3)). The thyroid gland actively transports iodine from the blood to synthesize these hormones. A deficiency in dietary iodine leads to impaired thyroid hormone production, which in turn stimulates the pituitary gland to release more TSH, leading to thyroid enlargement (goiter) in an attempt to capture more iodine. High iodine intake can paradoxically inhibit thyroid hormone synthesis (Wolff-Chaikoff effect).

Question 39

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

Accepted Answer

Is mediated by a chloride channel coupled to the secretion of bicarbonate. — In gastric parietal cells, the secretion of HCl into the gastric lumen involves the active pumping of H+ ions into the lumen via the H+/K+-ATPase. To maintain electrical neutrality, Cl- ions are secreted into the lumen through chloride channels, often coupled with the secretion of bicarbonate from the cell into the blood (alkaline tide) to balance the intracellular H+ secretion.

Question 40

Myeloid cells in innate and adaptive immunity EXCLUDE the following:

Accepted Answer

Plasma cells — Plasma cells are terminally differentiated B lymphocytes and are considered lymphoid cells, playing a crucial role in adaptive immunity by producing antibodies. Neutrophils, macrophages, and dendritic cells are all derived from myeloid progenitor cells and are key components of innate immunity, with dendritic cells also bridging to adaptive immunity.

Question 41

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

Accepted Answer

They include erythrocytes and megakaryocytes. — Erythrocytes (red blood cells) and megakaryocytes (which give rise to platelets) arise from the common myeloid progenitor, not the common lymphoid progenitor. The common lymphoid progenitor gives rise to B lymphocytes, T lymphocytes, and Natural Killer (NK) cells, which are all involved in adaptive and innate immunity.

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 atoms fatty acid through the citric acid cycle yields

Accepted Answer

More than 38 moles of ATP — The complete aerobic oxidation of a 6-carbon fatty acid (like palmitate, which is 16 carbons) through beta-oxidation and the citric acid cycle yields significantly more ATP than glucose. A 6-carbon fatty acid would undergo 2 rounds of beta-oxidation, producing 3 acetyl-CoA molecules, and then these would enter the citric acid cycle. Each acetyl-CoA yields about 10-12 ATP. Thus, 3 acetyl-CoA would yield approximately 30-36 ATP from the citric acid cycle and beta-oxidation itself produces FADH2 and NADH. Overall, the catabolism of a 6-carbon fatty acid yields substantially more ATP than a 6-carbon glucose molecule.

Question 43

25. Immune privileged sites include the following EXCEPT:

Accepted Answer

Spleen — Immune privileged sites are areas of the body where the immune system's response is reduced to prevent damage to vital tissues. These include the brain, eyes, and testes. The spleen, however, is a key organ of the immune system, involved in filtering blood and housing immune cells; it is not considered an immune privileged site.

Question 44

40. The human genome

Accepted Answer

Consists of approximately 3.2 billion base pairs. — The human genome contains approximately 3.2 billion base pairs. The number of protein-coding genes is estimated to be around 20,000-25,000, not 200,000. The genome contains both exons and introns. While there are many similarities, there are significant genetic variations among individuals.

Question 45

61. The following are characteristics of skeletal muscle fibres EXCEPT:

Accepted Answer

Single nucleus per cell — Skeletal muscle fibers are multinucleated, meaning they contain multiple nuclei per cell. They are characterized by their striated appearance due to the organized arrangement of actin and myosin filaments, their voluntary control, and their ability to contract forcefully.

Question 46

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

Accepted Answer

Tetanus — Tetanus refers to the sustained, forceful contraction of a muscle that occurs when the frequency of stimulation is high enough that individual muscle twitches fuse together, resulting in no apparent relaxation between stimuli.

Question 47

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

Accepted Answer

All of the above — The sensory cortex (somatosensory cortex) is responsible for processing all types of somatic sensations, including pain, touch, temperature, pressure, and proprioception (the sense of body position and movement). Therefore, a lesion in the sensory cortex would affect all these types of sensations.

Question 48

4. 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 allow for unidirectional transmission, while electrical synapses can be bidirectional. — While chemical synapses are typically unidirectional due to the release of neurotransmitters from the presynaptic neuron and their binding to receptors on the postsynaptic neuron, electrical synapses, connected by gap junctions, can allow for bidirectional transmission of electrical signals.

Question 49

Glucosuria is usually present without ketonuria.

Accepted Answer

Renal glycosuria — Renal glycosuria is a condition where glucose appears in the urine despite normal or near-normal blood glucose levels. This occurs when the renal tubules' reabsorptive capacity for glucose is exceeded, usually due to a reduced renal threshold for glucose. In true diabetes mellitus (Types 1 and 2, and Gestational), significant hyperglycemia is the primary cause of glucosuria, and ketonuria may be present, especially in Type 1 or uncontrolled diabetes.

Question 50

Which of the following substances is an inhibitor of glycolysis?

Accepted Answer

Monoiodoacetate — Monoiodoacetate is a potent inhibitor of glycolysis. It inhibits the enzyme glyceraldehyde-3-phosphate dehydrogenase by alkylating a critical cysteine residue in the active site. Maleimide is also an alkylating agent and can inhibit enzymes, but monoiodoacetate is a classic glycolytic inhibitor. Sodium fluoride can inhibit enolase in vitro. Cresol is a general cellular toxin.

Weekly Pathology Exam - August 28, 2026 (Section A: MCQs)

Questions, Answers & Explanations