NEET-PG 2015 Practice Questions

Q: Trigone of bladder is derived from?

Mesonephric duct. The trigone of the bladder is formed from the caudal ends of the **mesonephric ducts**, which are absorbed into the primitive bladder wall [1]. This mesenchymal origin explains why the trigone has a smooth lining [1] and is less prone to infection compared to the rest of the bladder. *Paramesonephric duct* - The **paramesonephric ducts** (Müllerian ducts) are involved in forming the female reproductive organs, specifically the fallopian tubes, uterus [2], and upper vagina. - They do not contribute to the formation of the urinary bladder or its trigone. *Absorbed anal membrane* - The **anal membrane** separates the endoderm-derived hindgut from the ectoderm-derived anal pit. - Its absorption is relevant to the development of the anus, not the urinary bladder. *Mullerian duct* - The **Müllerian ducts** are synonymous with the paramesonephric ducts and are primarily involved in the development of the female reproductive tract [2]. - They play no role in the development of the urinary bladder or its trigone.

Q: B cells are located in which region of lymph nodes?

Cortical follicles. ***Cortical follicles*** - **B cells** are predominantly found within the **cortical follicles** of lymph nodes, where they mature and become activated upon encountering antigens [2]. - These follicles can be primary (inactive) or secondary (active, containing **germinal centers** for B cell proliferation and differentiation). *Paracortical region* - The **paracortical region** is primarily occupied by **T cells** and is the site where T cells interact with antigen-presenting cells [1]. - While it's adjacent to B cell areas, it's not the primary location for B cells. *Medullary sinuses* - **Medullary sinuses** are channels in the medulla of the lymph node, containing macrophages and plasma cells, which are *differentiated B cells*. - They are not the primary residence for undifferentiated B cells. *Subcapsular region* - **Subcapsular region** is the space immediately beneath the capsule of the lymph node where lymph initially enters. - It contains macrophages and dendritic cells that sample antigens but is not a primary B cell zone.

Q: Pruritus [Itching] associated with Congenital Erythropoietic Porphyria is caused by deficiency of -

Uroporphyrinogen - III synthase. ***Uroporphyrinogen - III synthase*** - Congenital Erythropoietic Porphyria (CEP) is caused by a **deficiency of uroporphyrinogen III synthase**, leading to the accumulation of uroporphyrinogen I and coproporphyrinogen I. - These accumulated **Type I porphyrinogens** are non-functional in heme synthesis and are highly **photoreactive**, causing the characteristic photosensitivity and skin symptoms, including intense pruritus. *5-ALA dehydratase* - Deficiency of **5-ALA dehydratase** (also known as porphobilinogen synthase) is associated with **ALA dehydratase deficiency porphyria (ADP)**, a very rare acute hepatic porphyria. - Symptoms primarily involve **neurovisceral attacks** and do not typically include pruritus or photosensitivity. *Uroporphyrinogen - I synthase* - **Uroporphyrinogen I synthase** is an outdated and incorrect term; the correct enzyme in the heme synthesis pathway is **hydroxymethylbilane synthase (HMB synthase)** or **porphobilinogen deaminase (PBG deaminase)**, which synthesizes HMB. - Deficiency in HMB synthase leads to **acute intermittent porphyria (AIP)**, characterized by acute neurological attacks, not severe pruritus. *HMB synthase* - **HMB synthase** (hydroxymethylbilane synthase), also known as **porphobilinogen deaminase (PBG deaminase)**, is deficient in **acute intermittent porphyria (AIP)**. - AIP is marked by intermittent neurological dysfunction and abdominal pain, with **no significant photosensitivity or pruritus**.

Q: Most important carbohydrate store for maintaining blood glucose homeostasis -

Hepatic glycogen. ***Hepatic glycogen*** - The liver contains **100-120g of glycogen**, which is the most crucial carbohydrate store for **maintaining blood glucose homeostasis**. - **Hepatic glycogen** can be mobilized and released as glucose into the bloodstream to supply all body tissues, especially during fasting. - Although muscle glycogen is quantitatively larger (~400-500g), it cannot contribute to blood glucose as muscle lacks glucose-6-phosphatase. - The liver's unique ability to release free glucose makes hepatic glycogen the **most metabolically important** carbohydrate store. *Blood glucose* - **Blood glucose** (~5g total in circulation) represents carbohydrates available for immediate energy, not a storage form. - This is far too small to be considered a major carbohydrate reserve. *Glycogen in adipose tissue* - **Adipose tissue** primarily stores **fat (triglycerides)**, with negligible glycogen content. - Adipose tissue plays virtually no role in carbohydrate storage. *None of the options* - This is incorrect because **hepatic glycogen** is indeed the most important carbohydrate store for glucose homeostasis.

Q: What does Ghon's focus indicate in the context of tuberculosis?

Primary complex. ***Primary complex*** - A **Ghon's focus** is the initial parenchymal lesion (typically subpleural) that develops during primary tuberculosis infection [1]. - The Ghon's focus, together with an enlarged regional lymph node (usually hilar or mediastinal), forms the **Ghon's complex** or **Primary complex** [2]. - When this complex undergoes calcification and healing, it is called a **Ranke complex**, which indicates past healed primary TB. *Post primary tuberculosis* - Also known as **reactivation tuberculosis** or **secondary tuberculosis**, this typically occurs years after the primary infection, usually in the apices of the lungs [2]. - It represents reactivation of dormant bacilli, not the initial primary infection lesion. - Characterized by cavitary lesions and often more severe pulmonary symptoms. *Miliary tuberculosis* - This is a form of progressive, widespread tuberculosis characterized by the presence of **tiny, millet-seed sized lesions** disseminated throughout the body via hematogenous spread [3]. - It indicates a severe and life-threatening form of TB resulting from massive lymphohematogenous dissemination. - Not related to the localized primary complex. *Tuberculous lymphadenitis* - This refers to **tuberculous infection of lymph nodes**, most commonly in the cervical region (scrofula). - While lymph node involvement is part of the primary complex, Ghon's focus specifically refers to the **parenchymal lung lesion**, not the lymph node component alone [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 379-380. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 319-320. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 320-321.

Q: What is the first cellular response observed after a sharp nerve cut?

Chromatolysis. ***Chromatolysis*** - **Chromatolysis** is the dissolution of the Nissl bodies (rough endoplasmic reticulum) in the neuron cell body following axonal injury, which is the **first observable cellular response** [1]. - This process is a preparatory step for neuronal regeneration, indicating the cell's attempt to repair the damaged axon [1]. *Polymorphic arrangement* - This term is not typically used to describe an immediate cellular response to a nerve cut; it might refer to diverse cell shapes or arrangements in different contexts but is not a recognized initial post-injury event. - The neuron's immediate response involves changes within the cell body, not a re-arrangement of its cellular structure with other cells. *Increased protein synthesis* - While increased protein synthesis does occur during neuronal repair and regeneration, it is a consequence of chromatolysis and part of a later, more sustained response, not the very first visible cellular change [1]. - **Chromatolysis precedes** and facilitates the subsequent increase in protein synthesis necessary for axonal regrowth [1]. *Macrophage activation* - **Macrophage activation** is a crucial part of the inflammatory response and debris clearance following nerve injury, but it is not the *first cellular response* of the neuron itself [2]. - Macrophages migrate to the site of injury hours to days after the initial insult, whereas chromatolysis begins within the neuron's cell body much earlier [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1254-1256. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 697-698.

Q: Alkaline diuresis in drug poisoning is not done in?

Morphine. ***Morphine*** - **Morphine** is an **alkaline drug**, so its elimination is actually enhanced by **acidification of the urine**, not alkalinization. - Alkaline diuresis would decrease the ionization of morphine in the renal tubules, leading to **increased reabsorption** and reduced excretion. *Aspirin* - **Aspirin (acetylsalicylic acid)** is an **acidic drug**, and **alkaline diuresis** is effective in increasing its excretion by trapping the ionized form in the renal tubules. - This process prevents reabsorption and promotes clearance, which is a standard treatment for aspirin overdose. *Methotrexate* - **Methotrexate** is a **weak organic acid**, and **alkaline diuresis** is crucial in reducing its toxicity, especially in high-dose therapy. - By increasing urine pH, the renal elimination of methotrexate is significantly enhanced, preventing kidney damage and systemic accumulation. *Phenobarbitone* - **Phenobarbitone** is a **weak acid**, and **alkaline diuresis** is a well-established method to increase its renal excretion in cases of overdose. - Alkalinization of the urine promotes the ionization of phenobarbitone, reducing its reabsorption by the renal tubules and accelerating its elimination.

Q: Which of the following is not a known side effect of amiodarone?

Hyperglycemia. ***Hyperglycemia*** - **Hyperglycemia** is generally **not recognized** as a direct or common side effect of amiodarone. - Amiodarone's primary action is on cardiac ion channels, and its metabolic effects typically involve thyroid function, not glucose regulation. *Hyperthyroidism* - Amiodarone contains **iodine**, which can induce **thyroid dysfunction**, including both hypo- and hyperthyroidism. - **Amiodarone-induced hyperthyroidism (AIH)** can occur due to increased thyroid hormone synthesis or destructive thyroiditis. *Peripheral neuropathy* - **Neurological side effects**, including **peripheral neuropathy**, are known to occur with chronic amiodarone use. - Symptoms often include **paresthesias**, weakness, and sensory loss in the extremities. *Skin discoloration* - Prolonged use of amiodarone can lead to **bluish-gray skin discoloration**, particularly in sun-exposed areas. - This is due to the **accumulation of amiodarone** and its metabolites in the skin.

Q: What is the primary mechanism of action of zonisamide?

Sodium channels. ***Sodium channels (Correct Answer)*** - Zonisamide's primary mechanism involves **blocking voltage-sensitive sodium channels**, which stabilizes neuronal membranes and inhibits repetitive neuronal firing. - This action helps to prevent the propagation of **seizure activity** in the brain. *GABA receptors* - While zonisamide has some weak effects on GABA, it is not its **primary mechanism of action** for antiepileptic efficacy. - Drugs like **benzodiazepines** and **barbiturates** primarily act by enhancing GABAergic transmission. *T-type calcium channels* - Zonisamide also blocks T-type calcium channels, contributing to its broad-spectrum antiepileptic activity, but this is a **secondary mechanism** compared to its sodium channel blockade. - **Ethosuximide** is a classic example of a drug primarily acting on T-type calcium channels, especially for absence seizures. *Cl- channels* - Zonisamide does not primarily act on **chloride channels**; these are often modulated by GABA receptors. - Drugs that act directly on chloride channels are not typically used as **antiepileptics** in the same way.

Q: What is the drug of choice for drug-induced peptic ulcer?

Proton pump inhibitors. ***Proton pump inhibitors*** - **PPIs** are the most effective agents for treating and preventing **NSAID-induced peptic ulcers** by profoundly suppressing gastric acid secretion. - They provide **rapid symptom relief** and promote ulcer healing by creating an environment conducive to mucosal repair. *Prostaglandin analogues* - **Misoprostol**, a prostaglandin E1 analogue, can prevent NSAID-induced ulcers, but its use is limited by **gastrointestinal side effects** such as diarrhea and abdominal cramping. - While they protect the gastric mucosa, their efficacy in healing established ulcers is generally **inferior to PPIs**. *H2-receptor antagonists* - **H2-blockers** are effective in reducing gastric acid, but they are **less potent** than PPIs and typically do not heal **gastric ulcers** as effectively, especially those induced by NSAIDs. - They are more commonly used for preventing **duodenal ulcers** and managing symptoms of GERD. *Antacids* - Antacids provide **immediate, temporary relief** of ulcer symptoms by neutralizing existing stomach acid. - They do not address the underlying pathology or promote **ulcer healing** and are therefore not considered the drug of choice for treatment.

Question 1

Trigone of bladder is derived from?

Accepted Answer

Mesonephric duct

Answer

Paramesonephric duct

Answer

Absorbed anal membrane

Answer

Mullerian duct

Question 2

B cells are located in which region of lymph nodes?

Accepted Answer

Cortical follicles

Answer

Paracortical region

Answer

Subcapsular region

Answer

Medullary sinuses

Question 3

Pruritus [Itching] associated with Congenital Erythropoietic Porphyria is caused by deficiency of -

Accepted Answer

Uroporphyrinogen - III synthase

Answer

Uroporphyrinogen - I synthase

Answer

5-ALA dehydratase

Answer

HMB synthase

Question 4

Most important carbohydrate store for maintaining blood glucose homeostasis -

Accepted Answer

Hepatic glycogen

Answer

Blood glucose

Answer

Glycogen in adipose tissue

Answer

None of the options

Question 5

What does Ghon's focus indicate in the context of tuberculosis?

Accepted Answer

Primary complex

Answer

Post primary tuberculosis

Answer

Miliary tuberculosis

Answer

Tuberculous lymphadenitis

Question 6

What is the first cellular response observed after a sharp nerve cut?

Accepted Answer

Chromatolysis

Answer

Polymorphic arrangement

Answer

Increased protein synthesis

Answer

Macrophage activation

Question 7

Alkaline diuresis in drug poisoning is not done in?

Accepted Answer

Morphine

Answer

Aspirin

Answer

Phenobarbitone

Answer

Methotrexate

Question 8

Which of the following is not a known side effect of amiodarone?

Accepted Answer

Hyperglycemia

Answer

Peripheral neuropathy

Answer

Hyperthyroidism

Answer

Skin discoloration

Question 9

What is the primary mechanism of action of zonisamide?

Accepted Answer

Sodium channels

Answer

GABA receptors

Answer

Cl- channels

Answer

T-type calcium channels

Question 10

What is the drug of choice for drug-induced peptic ulcer?

Accepted Answer

Proton pump inhibitors

Answer

Prostaglandin analogues

Answer

H2-receptor antagonists

Answer

Antacids

NEET-PG 2015

Anatomy

Biochemistry

Pathology

Pharmacology