NEET-PG 2019 Practice Questions

Q: Cholecystocaval line:-

Separate right and left hepatic lobes. ***Separate right and left hepatic lobes*** - The **cholecystocaval line**, also known as **Cantlie's line**, is an imaginary plane that divides the **anatomical right and left lobes** of the liver [1]. - This line runs from the **gallbladder fossa** anteriorly to the **inferior vena cava (IVC)** posteriorly. *Separate left medial and left lateral sectors* - The division between the **left medial (segment IV)** and **left lateral (segments II and III)** sectors of the liver is demarcated by the **left hepatic vein** or the falciform ligament internally [3], [4]. - The cholecystocaval line's primary function is not to separate these specific left lobe sectors. *Separate right anterior and right posterior sectors* - The division between the **right anterior (segments V and VIII)** and **right posterior (segments VI and VII)** sectors of the liver is typically defined by the **right hepatic vein** [2]. - This anatomical landmark is distinct from the cholecystocaval line. *Separate gall bladder from portal vein* - The cholecystocaval line is a plane that **originates from the gallbladder**, but it divides the liver parenchyma rather than separating the gallbladder itself from the portal vein. - The gallbladder is a separate organ adjacent to the liver, and the portal vein is a major vessel within the liver parenchyma [1].

Q: Frey's syndrome occurs due to aberrant regeneration of parasympathetic nerve fibers following parotid surgery, leading to gustatory sweating. The nerve directly involved in this aberrant reinnervation is:

Auriculotemporal nerve. ***Auriculotemporal nerve*** - Frey's syndrome, or **gustatory sweating**, occurs due to damage to the **auriculotemporal nerve**, typically during parotidectomy. - Aberrant regeneration leads to misdirection of parasympathetic fibers meant for the parotid gland to the sweat glands in the preauricular and temporal regions. *Trigeminal nerve* - The trigeminal nerve (CN V) is primarily responsible for **sensory innervation of the face** and **motor innervation of the muscles of mastication**. - It does not directly provide secretomotor innervation to the parotid gland or sweat glands. *Facial nerve* - The facial nerve (CN VII) innervates the **muscles of facial expression** and provides taste sensation to the anterior two-thirds of the tongue, and secretomotor innervation to the submandibular and sublingual glands. - While it passes through the parotid gland, it does not provide secretomotor innervation to the parotid gland itself. *GlossoPharyngeal nerve* - The glossopharyngeal nerve (CN IX) provides presynaptic parasympathetic fibers to the **otic ganglion**, which then synapse with postsynaptic fibers carried by the auriculotemporal nerve to the parotid gland. - Although it is the origin of the parasympathetic innervation for the parotid, the direct aberrant reinnervation in Frey's syndrome involves the auriculotemporal nerve, not the glossopharyngeal nerve itself.

Q: True regarding mitochondrial DNA is:

Inherited from mother. ***Inherited from mother*** - **Mitochondrial DNA (mtDNA)** is exclusively inherited from the mother because the sperm's mitochondria are typically destroyed after fertilization or do not enter the oocyte. - This **maternal inheritance pattern** makes mtDNA useful for tracing lineage and studying human population movements. *Linear double stranded* - **Mitochondrial DNA** is typically **circular**, not linear, and double-stranded, similar to a plasmid in bacteria. - **Linear DNA** is characteristic of nuclear chromosomes in eukaryotes. *All respiratory proteins are synthesized within mitochondria itself* - While mitochondria contain their own ribosomes and synthesize some proteins, the majority of **respiratory chain proteins** are encoded by **nuclear DNA** and imported into the mitochondria. - The **mitochondrial genome** encodes only a small fraction of the proteins necessary for mitochondrial function, primarily components of the electron transport chain. *Low mutation rate* - **Mitochondrial DNA** has a **higher mutation rate** compared to nuclear DNA due to a less robust DNA repair system and exposure to reactive oxygen species generated during oxidative phosphorylation. - The high mutation rate can contribute to mitochondrial diseases and can also be used in evolutionary studies.

Q: MHC II is associated with:-

Antigen presenting cells. ***Antigen presenting cells*** - **MHC II (Major Histocompatibility Complex class II)** molecules are primarily expressed on the surface of professional **antigen-presenting cells (APCs)**. - APCs, such as **macrophages**, **dendritic cells**, and **B lymphocytes**, use MHC II to present **extracellularly derived antigens** to **CD4+ T helper cells**. *Red blood cells* - **Red blood cells (RBCs)** are anucleated and lack MHC molecules entirely. - Their primary function is **oxygen transport**, not immune cell communication. *Platelets* - **Platelets** are cell fragments involved in **hemostasis** (blood clotting). - They do not express MHC class II molecules as they are not involved in antigen presentation. *Epithelial cells* - Most **epithelial cells** primarily express **MHC class I** molecules to present **intracellular antigens** to **CD8+ cytotoxic T cells**. - They do not typically express MHC class II unless under specific inflammatory conditions, and even then, not as their primary function.

Q: Scaphoid fracture which area has maximum chances of AVN/Non-union/Malunion:-

Proximal 1/3. ***Proximal 1/3*** - The **proximal pole of the scaphoid** has a precarious blood supply, primarily from retrograde extraosseous vessels entering distally. A fracture in this region can compromise this supply, leading to **avascular necrosis (AVN)**. - Due to the limited blood flow to the proximal fragment, healing is often impaired, increasing the risk of **non-union** and **malunion**. *Distal 1/3* - Fractures in the **distal 1/3 (distal pole)** of the scaphoid typically have a better prognosis. - This area has a more robust blood supply, reducing the risk of AVN and promoting faster healing. *Scaphoid Tubercle fracture* - Fractures of the **scaphoid tubercle** are usually considered stable and intra-articular, with a good blood supply. - These fractures generally heal well with conservative treatment and have a very low incidence of AVN or non-union. *Middle 1/3* - Fractures in the **middle 1/3 (waist)** of the scaphoid are the most common but still pose a significant risk of non-union. - While the risk of AVN is lower than for proximal pole fractures, it is still higher than for distal fractures, due to the critical vascular supply to both fragments.

Q: Characteristic feature of hypertrophic obstructive cardiomyopathy is:

Asymmetric septal hypertrophy. ***Asymmetric septal hypertrophy*** - This is the hallmark feature of **hypertrophic obstructive cardiomyopathy (HOCM)**, where the **interventricular septum** thickens disproportionately more than the free wall of the left ventricle [1], [2]. - This septal thickening can lead to **left ventricular outflow tract obstruction**, particularly during systole, obstructing blood flow out of the heart [1]. *Increased size of ventricle* - While the left ventricle may appear enlarged in some dimensions due to hypertrophy, the primary characteristic is specifically **asymmetric thickening of the septum**, not a generalized increase in ventricular size [2]. - In other forms of cardiomyopathy, such as dilated cardiomyopathy, a global increase in ventricular size is observed, which is distinct from HOCM. *Normal myofiber arrangement* - A characteristic microscopic feature of HOCM is **myocardial disarray**, where cardiac muscle fibers are abnormally arranged instead of their usual parallel alignment [1]. - This disorganized arrangement contributes to the impaired function and electrical instability seen in HOCM. *Increased size of atria* - While **left atrial enlargement** can be a secondary finding in HOCM due to increased left ventricular end-diastolic pressure and impaired diastolic filling, it is not the primary or characteristic feature defining the condition [1]. - The fundamental pathology of HOCM lies in the specific hypertrophy of the ventricular myocardium, particularly the septum. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 577-578. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Cardiovascular Disease, pp. 303-304.

Q: Which chamber of the heart is enlarged first in a patient with McCallum patch?

Left atrium. ***Left atrium*** - A **McCallum patch** is a thickened, often irregular endocardial lesion found in the **left atrium**. - It results from the jet lesion of **mitral regurgitation**, indicating the left atrium has been subjected to increased volume and pressure leading to enlargement [1]. *Left ventricle* - While **mitral regurgitation** can eventually lead to **left ventricular enlargement** (due to volume overload), the primary chamber affected by the regurgitant jet causing the McCallum patch is the left atrium. - Left ventricular enlargement is a later consequence, not the first chamber to show this specific lesion. *Right atrium* - The **right atrium** is affected by conditions like **tricuspid regurgitation** or **pulmonary hypertension**, which are unrelated to mitral valve disease or McCallum patches. - It handles systemic venous return, separate from the left-sided circulation involved in mitral pathology. *Right ventricle* - The **right ventricle** is primarily impacted by conditions affecting the **pulmonary circulation** or **tricuspid valve**. - It fills from the right atrium and pumps blood to the lungs, making it unlikely to be the first chamber enlarged in the context of a McCallum patch from mitral regurgitation. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 533-534.

Q: Mechanism of action of teduglutide in short bowel syndrome:

GLP-2 analog that inhibits apoptosis. ***GLP-2 analog that inhibits apoptosis*** - **Teduglutide** is a synthetic analog of **glucagon-like peptide-2 (GLP-2)**, which is a naturally occurring human hormone [1]. - Its primary mechanism in **short bowel syndrome** involves promoting mucosal growth and inhibiting epithelial cell apoptosis, thereby enhancing nutrient absorption and gut adaptation. *GLP-1 analogs that inhibits apoptosis* - **GLP-1 analogs** like exenatide or liraglutide are primarily used for **type 2 diabetes mellitus** to stimulate insulin secretion and suppress glucagon [2]. - While they can have some effects on gut motility, their main role is not in promoting mucosal growth or inhibiting apoptosis in the context of short bowel syndrome. *HT1A inhibitor* - **HT1A inhibitors** (5-HT1A receptor antagonists) are typically involved in modulating serotonin pathways, often with applications in conditions like **anxiety** or **depression**. - There is no known direct link between HT1A inhibition and the treatment of short bowel syndrome. *C-peptide analogs* - **C-peptide** is a byproduct of insulin production and has been studied for potential roles in preventing diabetes complications, particularly in relation to **microvascular complications** [3], [4]. - It does not play a direct role as a therapeutic agent for promoting intestinal adaptation or inhibiting apoptosis in short bowel syndrome.

Q: Mannitol is used in the management of:-

Acute angle-closure glaucoma. ***Acute angle-closure glaucoma*** - **Mannitol** is an osmotic diuretic [1] used to rapidly reduce **intraocular pressure** in conditions like acute angle-closure glaucoma [2]. - It works by creating an **osmotic gradient** that draws fluid from the vitreous humor into the bloodstream [2]. - This is a well-established **emergency indication** for mannitol [2]. *Acute renal failure* - While mannitol may be used in **prevention** of acute kidney injury (e.g., in rhabdomyolysis, cardiovascular surgery) [2], its use in established acute renal failure is generally **contraindicated** if the patient is **anuric**, as it can exacerbate fluid overload [2]. - It is **not a primary management** for acute renal failure among the given options. *Pulmonary edema* - **Mannitol** is generally **contraindicated** in pulmonary edema because its initial effect is to increase **intravascular volume** [2], which can worsen fluid accumulation in the lungs. - Loop diuretics like **furosemide** are preferred for their rapid onset and profound diuretic effect in pulmonary edema. *Congestive cardiac failure* - **Mannitol** is typically **contraindicated** in congestive cardiac failure as it can cause a **transient increase in plasma volume**, potentially worsening cardiac workload and leading to decompensation [2]. - Diuretics commonly used in heart failure, such as **loop diuretics** (e.g., furosemide) or **thiazide diuretics**, are preferred to reduce fluid overload.

Q: Degloving injury involves separation of:-

Skin + Fascia + Subcutaneous tissue. ***Skin + Fascia + Subcutaneous tissue*** - A **degloving injury** involves the traumatic separation of skin, subcutaneous tissue, and **superficial fascia** from the underlying deep fascia and muscle structures. - The separation typically occurs at the plane between the **superficial fascia** and **deep fascia**, creating the characteristic "degloved" appearance with loss of multiple tissue layers. *Skin + Subcutaneous tissue* - This option is incomplete as it fails to explicitly mention the **superficial fascia** component that is also involved in degloving injuries. - While anatomically the subcutaneous tissue includes fascial elements, the complete description should specifically include **fascia** as a separate component. *Skin* - This option is severely incomplete as degloving injuries involve much more than just the **epidermal and dermal layers**. - A true degloving injury must include separation of the **subcutaneous tissue** and **superficial fascia** to create the characteristic tissue defect. *Everything above from bone* - This description is too extensive and would represent a **complex avulsion** or **near-amputation** rather than a typical degloving injury. - Degloving specifically refers to separation at the **superficial-deep fascial plane**, not removal of all overlying tissues including muscle and deep fascia.

Question 1

Cholecystocaval line:-

Accepted Answer

Separate right and left hepatic lobes

Answer

Separate left medial and left lateral sectors

Answer

Separate right anterior and right posterior sectors

Answer

Separate gall bladder from portal vein

Question 2

Frey's syndrome occurs due to aberrant regeneration of parasympathetic nerve fibers following parotid surgery, leading to gustatory sweating. The nerve directly involved in this aberrant reinnervation is:

Accepted Answer

Auriculotemporal nerve

Answer

Trigeminal nerve

Answer

Facial nerve

Answer

GlossoPharyngeal nerve

Question 3

True regarding mitochondrial DNA is:

Accepted Answer

Inherited from mother

Answer

Linear double stranded

Answer

All respiratory proteins are synthesized within mitochondria itself

Answer

Low mutation rate

Question 4

MHC II is associated with:-

Accepted Answer

Antigen presenting cells

Answer

Red blood cells

Answer

Platelets

Answer

Epithelial cells

Question 5

Scaphoid fracture which area has maximum chances of AVN/Non-union/Malunion:-

Accepted Answer

Proximal 1/3

Answer

Distal 1/3

Answer

Scaphoid Tubercle fracture

Answer

Middle 1/3

Question 6

Characteristic feature of hypertrophic obstructive cardiomyopathy is:

Accepted Answer

Asymmetric septal hypertrophy

Answer

Increased size of ventricle

Answer

Normal myofiber arrangement

Answer

Increased size of atria

Question 7

Which chamber of the heart is enlarged first in a patient with McCallum patch?

Accepted Answer

Left atrium

Answer

Left ventricle

Answer

Right atrium

Answer

Right ventricle

Question 8

Mechanism of action of teduglutide in short bowel syndrome:

Accepted Answer

GLP-2 analog that inhibits apoptosis

Answer

HT1A inhibitor

Answer

C-peptide analog

Answer

GLP-1 analog that inhibits apoptosis

Question 9

Mannitol is used in the management of:-

Accepted Answer

Acute angle-closure glaucoma

Answer

Acute renal failure

Answer

Pulmonary edema

Answer

Congestive cardiac failure

Question 10

Degloving injury involves separation of:-

Accepted Answer

Skin + Fascia + Subcutaneous tissue

Answer

Skin

Answer

Everything above from bone

Answer

Skin + Subcutaneous tissue

NEET-PG 2019

Anatomy

Biochemistry

Microbiology

Orthopaedics

Pathology

Pharmacology

Surgery