FMGE 2023 Practice Questions

Q: Which of the following is the right lateral rectus yoke muscle?

Left medial rectus. ***Left medial rectus***- The **yoke muscle** concept is based on **Hering's Law of Equal Innervation**, which requires equal stimulation for the muscle pair responsible for parallel movement in both eyes.- When the **right lateral rectus** abducts the right eye during gaze to the right (**dextroversion**), the **left medial rectus** must simultaneously adduct the left eye to maintain conjugate gaze [1]. *Right superior oblique*- This muscle primarily causes **intorsion** and depression of the right eye, and is not involved in primary lateral movements [1].- It acts conjugately with the **Left Inferior Rectus** when the gaze is directed down and to the right. *Left lateral rectus*- This muscle is responsible for **abduction of the left eye**, which contributes to gaze to the **left (levoversion)** [1].- It is the yoke muscle for the **Right medial rectus**. *Right medial rectus*- This muscle is the **antagonist** of the right lateral rectus, responsible for adduction of the right eye [1].- It works with the left lateral rectus when moving the gaze to the **left (levoversion)**.

Q: In relation to which wall of the orbit are the canaliculi that open into the lacrimal sac present?

Medial wall. ***Medial wall*** - The **lacrimal sac**, into which the canaliculi open, is lodged in the **lacrimal fossa**, which is anatomically a component of the medial wall of the orbit [1]. - Both the superior and inferior **lacrimal canaliculi** run medially from their respective puncta towards the lacrimal sac, confirming their close association with the medial wall. *Lateral wall* - This wall is primarily formed by the **zygomatic bone** and the greater wing of the **sphenoid**, serving mainly for muscular attachment (e.g., lateral rectus). - It is completely separated from the lacrimal drainage apparatus, which is confined to the medial aspect of the orbit. *Superior wall* - The superior wall (roof) is chiefly composed of the **frontal bone** and separates the orbit from the **anterior cranial fossa**. - Although the lacrimal gland is housed in a fossa on the roof's anterolateral aspect, the excretory part (sac and canaliculi) is located medially. *Inferior wall* - The inferior wall (floor) is mainly formed by the **maxilla** and separates the orbit from the **maxillary sinus** [1]. - It contains the **infraorbital groove and canal** but is anatomically distant from the structures involved in tear drainage into the lacrimal sac.

Q: A 68-year-old female patient has had a diabetic cataract for 3 months. Accumulation of which of the following substances is responsible for this?

Sorbitol + Fructose. ***Sorbitol + Fructose*** This option correctly identifies the products of the **polyol pathway**, which is significantly activated in lens fibers during **hyperglycemia**. **Sorbitol** is the key substance that accumulates due to high **aldose reductase** activity and low sorbitol dehydrogenase activity, leading to an **osmotic gradient** and water accumulation, causing lens swelling and opacification (cataract). *Glucose* Although high blood **glucose** initiates the process by serving as the substrate for aldose reductase, glucose itself is not the primary substance responsible for the osmotic damage in the lens. In normal lens metabolism, glucose is primarily metabolized via **glycolysis**; only when levels are excessive is the polyol pathway significantly utilized. *Fructose* Fructose is the breakdown product of **sorbitol** (catalyzed by sorbitol dehydrogenase), but its concentration is typically much lower than sorbitol in the lens. **Sorbitol** accumulation is the primary driver of the powerful osmotic effect that leads to water influx into the lens fiber cells and subsequent cataract formation. *Lactose + Glucose* Accumulation of **lactose** is not associated with diabetic cataract; this combination is irrelevant to the pathogenesis of hyperglycemia-induced lens damage. **Galactosemic cataract**, a different type of osmotic cataract, is caused by the accumulation of **galactitol** (a polyol derived from galactose, not glucose).

Q: Which of the following correctly represents the effect of the mutation causing sickle cell anemia?

Glutamate by valine at the 6th position. ***Glutamate by valine at the 6th position***- This mutation involves a single nucleotide substitution (A to T) in the $\beta$-globin gene, resulting in the replacement of hydrophilic **glutamate** with hydrophobic **valine** at the sixth position.- This change (E6V) creates a sticky patch on the **hemoglobin S (HbS)** molecule, leading to polymerization and sickling of red blood cells under conditions of low oxygen tension.*Valine by glutamate at the 6th position*- This represents the reverse substitution: replacing **valine** with **glutamate** at the 6th position.- This reversal of the substitution direction would describe the change from **HbS** back to the normal $\beta$-globin chain structure (**HbA**), not the cause of sickle cell anemia.*Glutamate by valine at the 5th position*- Although the amino acid substitution (**Glutamate** replaced by **Valine**) is correct, the position specified is inaccurate.- The critical substitution causing **sickle cell disease** is precisely at the **6th position** of the $\beta$-globin chain, not the 5th.*Valine by glutamate at the 5th position*- This option fails on two counts: the substitution direction is reversed (Valine $\rightarrow$ Glutamate), and the position of the mutation (**5th**) is incorrect.- The pathogenesis of sickle cell anemia depends on the replacement of the charged hydrophilic amino acid (**glutamate**) with the uncharged hydrophobic amino acid (**valine**) at position 6.

Q: A primigravida woman at 26 weeks gestation, presented with a BP of 150/90 mm Hg. Which test should be done next?

Urine dipstick. ***Urine dipstick***- The initial requirement for diagnosing **preeclampsia** is the presence of new-onset hypertension (BP > 140/90) plus **proteinuria** (or signs of end-organ damage).- The urine dipstick is the quickest and easiest initial test to rapidly screen for the presence of **proteinuria** and establish the correct diagnostic category (Gestational Hypertension vs. Preeclampsia).*Uric acid*- Elevated **serum uric acid** is often associated with preeclampsia severity, correlating with increased poor maternal and fetal outcomes.- However, it is not the standard *initial* diagnostic screening test needed to define the condition itself, which primarily requires checking for proteinuria.*Liver function test*- LFTs (AST and ALT) are performed to evaluate for signs of **severe preeclampsia** or **HELLP syndrome**, indicated by elevated transaminases.- While crucial for assessing severity, the initial step after noting hypertension is to screen for **proteinuria**, not necessarily end-organ damage markers.*Complete blood count*- A CBC is necessary to check for signs of severity, specifically **thrombocytopenia** (platelet count < 100,000/µL), which defines severe preeclampsia or HELLP syndrome.- Like LFTs, this is part of the workup for *severity* or *end-organ damage*, but the priority after detecting hypertension is confirming proteinuria via an initial screening test.

Q: Which of the following is a feature of hemolytic anemia?

Decreased haptoglobin. ***Decreased haptoglobin***- Hemolytic anemia involves the rapid breakdown of red blood cells, which releases **free hemoglobin** into the blood plasma. [1]- **Haptoglobin** rapidly binds to this free hemoglobin and is subsequently cleared by the **reticuloendothelial system**, leading to significantly reduced or absent plasma haptoglobin levels. [1]*All of the options given below*- This option is incorrect because both **neutropenia** and **reticulocytopenia** are generally *not* features of uncomplicated hemolytic anemia.*Neutropenia*- **Neutropenia** (low neutrophil count) is not typically associated with hemolytic anemia, which primarily affects the **red cell line**.- It is usually seen in conditions involving bone marrow failure (e.g., **aplastic anemia**) or destruction of white cells, not premature RBC destruction.*Reticulocytopenia*- Uncomplicated hemolytic anemia stimulates the bone marrow to produce new RBCs, resulting in **reticulocytosis** (increased reticulocytes) as a compensatory mechanism. [1]- **Reticulocytopenia** (low reticulocytes) is seen when the bone marrow cannot respond, such as during an **aplastic crisis** (often due to **Parvovirus B19** infection) or when the anemia is caused by true bone marrow failure. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 638-640.

Q: Tamm-Horsfall mucoprotein is a major component of which of the following?

Renal casts. ***Renal casts*** - **Tamm-Horsfall mucoprotein (THP)**, or **uromodulin**, is a glycoprotein synthesized by the tubular epithelial cells of the **thick ascending limb of the loop of Henle** and the distal tubule. - It forms the fundamental matrix of virtually all **renal casts** (hyaline, granular, waxy, fatty, etc.) when it precipitates in the concentrated, acidic environment of the distal nephron [1]. *Mural thrombi* - These are formed within blood vessels or the heart chambers and consist primarily of aggregated **platelets**, **fibrin**, and entrapped red blood cells. - Mural thrombi are related to circulatory pathology (e.g., atrial fibrillation, myocardial infarction) and are distinct from urinary tract components. *Curschmann spirals* - These spiral-shaped mucoid structures are found in the sputum of patients with conditions like severe bronchial **asthma** or chronic bronchitis. - They represent casts of small bronchi or bronchioles composed mainly of **mucus**, glycoproteins, and cellular debris produced by goblet cells and mucous glands. *Bence-Jones proteins* - These are **free monoclonal light chains** (kappa or lambda) of immunoglobulins that appear in the urine due to overproduction by pathologically proliferating plasma cells, most commonly in **multiple myeloma** [1]. - Bence-Jones proteins are filtered plasma proteins and are distinct from Tamm-Horsfall protein which is secreted by the renal tubular cells [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 942-943.

Q: Following urine microscopy and examination, a child is found to have hematuria and RBC casts in the urine. What is the probable cause for this?

Post-streptococcal glomerulonephritis (PSGN). ***Post-streptococcal glomerulonephritis (PSGN)***- RBC casts are highly indicative of **active glomerulonephritis**, demonstrating that red blood cells have leaked through damaged glomeruli and aggregated in the renal tubules.- **PSGN** is the most common cause of acute nephritic syndrome in children, typically following a *Streptococcal* infection, characterized by **hematuria**, hypertension, and mild proteinuria.*Focal segmental glomerulosclerosis (FSGS)*- FSGS almost universally presents as **nephrotic syndrome**, characterized by heavy **proteinuria**, profound edema, and hypoalbuminemia.- While microscopic hematuria may be present, the finding of **RBC casts** is highly uncommon and points away from a primary diagnosis of FSGS.*Membranoproliferative glomerulonephritis (MPGN)*- MPGN often presents with a **mixed nephrotic and nephritic picture**, including hematuria, but is less common acutely than PSGN in children.- PSGN presents with a very typical acute onset of **nephritic features** (hematuria, casts, hypertension) following infection, making it the more probable cause.*Minimal change disease*- This is the leading cause of **nephrotic syndrome** in children, defined by massive **proteinuria** with minimal to no damage visible on light microscopy.- **Minimal change disease** classically presents without significant hematuria and **RBC casts** are virtually absent.

Q: A 50-year-old woman was prescribed a diuretic by a doctor to manage hypertension. Which of the following diuretics acts on site 'A' as marked in the given image?

Hydrochlorothiazide. ***Hydrochlorothiazide*** - Hydrochlorothiazide is a **thiazide diuretic** that acts on the **Distal Convoluted Tubule (DCT)**, which is indicated by the letter 'A' in the provided diagram. - It works by inhibiting the **Na+/Cl- cotransporter** in the early DCT, leading to increased excretion of sodium and water, which helps lower blood pressure. *Furosemide* - Furosemide is a potent **loop diuretic** that acts on the **thick ascending limb of the loop of Henle** (labeled as 'G'). - It inhibits the **Na+/K+/2Cl- cotransporter**, causing a significant increase in sodium and water excretion, making it more powerful than thiazides. *Acetazolamide* - Acetazolamide is a **carbonic anhydrase inhibitor**, and its primary site of action is the **Proximal Convoluted Tubule (PCT)** (labeled as 'D'). - It is a weak diuretic and is more commonly used for glaucoma, metabolic alkalosis, or altitude sickness rather than as a primary agent for hypertension. *Mannitol* - Mannitol is an **osmotic diuretic** that exerts its effect primarily in the **Proximal Convoluted Tubule (PCT)** and the **descending limb of the loop of Henle**. - It is administered intravenously and is used to reduce intracranial or intraocular pressure, not for the chronic management of hypertension.

Q: Which of the following diuretics primarily acts on the part labeled 'D' in the given diagram of a nephron?

Hydrochlorothiazide. ***Hydrochlorothiazide*** - The part labeled 'D' in the diagram is the **Distal Convoluted Tubule (DCT)**. **Thiazide diuretics**, such as hydrochlorothiazide, primarily act on this segment of the nephron. - They work by inhibiting the **Na+/Cl- cotransporter** in the DCT, which reduces the reabsorption of sodium and chloride from the tubular fluid, leading to increased water excretion. *Furosemide* - Furosemide is a **loop diuretic** that acts on the **thick ascending limb of the Loop of Henle** (part of B), not the DCT. - It is a more potent diuretic than thiazides because it inhibits the **Na+-K+-2Cl- cotransporter**, which is responsible for reabsorbing a significant portion of filtered sodium. *Acetazolamide* - Acetazolamide is a **carbonic anhydrase inhibitor** that primarily acts on the **Proximal Convoluted Tubule (PCT)** (labeled 'A'). - Its mechanism involves reducing the reabsorption of **bicarbonate (HCO3-)**, which leads to a mild diuretic effect and can cause metabolic acidosis. *Mannitol* - Mannitol is an **osmotic diuretic** that acts mainly in the **Proximal Convoluted Tubule (PCT)** and the **descending limb of the Loop of Henle**. - It is a pharmacologically inert substance that increases the **osmolarity** of the tubular fluid, thereby preventing water reabsorption.

Question 1

Which of the following is the right lateral rectus yoke muscle?

Accepted Answer

Left medial rectus

Answer

Right superior oblique

Answer

Right medial rectus

Answer

Left lateral rectus

Question 2

In relation to which wall of the orbit are the canaliculi that open into the lacrimal sac present?

Accepted Answer

Medial wall

Answer

Superior wall

Answer

Inferior wall

Answer

Lateral wall

Question 3

A 68-year-old female patient has had a diabetic cataract for 3 months. Accumulation of which of the following substances is responsible for this?

Accepted Answer

Sorbitol + Fructose

Answer

Fructose

Answer

Lactose + Glucose

Answer

Glucose

Question 4

Which of the following correctly represents the effect of the mutation causing sickle cell anemia?

Accepted Answer

Glutamate by valine at the 6th position

Answer

Glutamate by valine at the 5th position

Answer

Valine by glutamate at the 5th position

Answer

Valine by glutamate at the 6th position

Question 5

A primigravida woman at 26 weeks gestation, presented with a BP of 150/90 mm Hg. Which test should be done next?

Accepted Answer

Urine dipstick

Answer

Uric acid

Answer

Liver function test

Answer

Complete blood count

Question 6

Which of the following is a feature of hemolytic anemia?

Accepted Answer

Decreased haptoglobin

Answer

Neutropenia

Answer

Reticulocytopenia

Answer

All of the above

Question 7

Tamm-Horsfall mucoprotein is a major component of which of the following?

Accepted Answer

Renal casts

Answer

Bence-Jones proteins

Answer

Mural thrombi

Answer

Curschmann spirals

Question 8

Following urine microscopy and examination, a child is found to have hematuria and RBC casts in the urine. What is the probable cause for this?

Accepted Answer

Post-streptococcal glomerulonephritis (PSGN)

Answer

Focal segmental glomerulosclerosis (FSGS)

Answer

Membranoproliferative glomerulonephritis (MPGN)

Answer

Minimal change disease

Question 9

A 50-year-old woman was prescribed a diuretic by a doctor to manage hypertension. Which of the following diuretics acts on site 'A' as marked in the given image?

Accepted Answer

Hydrochlorothiazide

Answer

Acetazolamide

Answer

Mannitol

Answer

Furosemide

Question 10

Which of the following diuretics primarily acts on the part labeled 'D' in the given diagram of a nephron?

Accepted Answer

Hydrochlorothiazide

Answer

Acetazolamide

Answer

Mannitol

Answer

Furosemide

FMGE 2023

Anatomy

Biochemistry

Obstetrics and Gynecology

Pathology

Pediatrics

Pharmacology