NEET-PG 2015 Practice Questions

Q: Which organ receives dual blood supply with both sources contributing to its primary metabolic function?

Liver. ***Liver*** - The liver receives blood from two sources: the **hepatic artery** (supplying oxygenated blood, ~25% of blood flow) and the **hepatic portal vein** (supplying nutrient-rich, deoxygenated blood from the gastrointestinal tract, ~75% of blood flow). - Both blood supplies are essential for the liver's primary metabolic functions, detoxification, and nutrient processing [1]. - This is the classic example of dual blood supply in medical education. *Heart* - The heart receives its blood supply primarily from the **coronary arteries**, which branch off the aorta. - While it has an extensive arterial network, it has a single primary source of blood supply. *Kidney* - The kidneys receive their blood supply exclusively from the **renal arteries**, which branch directly from the aorta. - Each kidney typically has a single renal artery supplying it for high-pressure filtration. *Lung* - The lungs do receive blood from two sources: **pulmonary arteries** (deoxygenated blood for gas exchange) and **bronchial arteries** (oxygenated blood for tissue nourishment, <5% of flow). - However, the primary function (gas exchange) is served by pulmonary circulation alone, while bronchial circulation only nourishes lung tissue. - The liver is the standard answer for dual blood supply where both sources serve the organ's primary function.

Q: Which type of thyroid cancer is associated with primary hyperparathyroidism and phaeochromocytoma?

Medullary carcinoma of the thyroid. ***Medullary carcinoma of the thyroid*** - Associated with **multiple endocrine neoplasia (MEN) syndrome type 2**, which includes primary hyperparathyroidism and phaeochromocytoma [1]. - Medullary carcinoma arises from **C cells** (parafollicular cells) and is linked with **elevated calcitonin** levels. *Papillary carcinoma of the thyroid* - The most common type of thyroid cancer, but **not associated** with MEN syndromes. - Typically presents as a solitary **nodule** and is linked with **radiation exposure** rather than endocrine syndromes. *Anaplastic carcinoma of the thyroid* - A highly aggressive and undifferentiated form of thyroid cancer, often associated with **poor prognosis**. - Usually arises in older adults and does not have associations with **hyperparathyroidism** or phaeochromocytoma. *Follicular carcinoma of the thyroid* - Characterized by **thyroid follicle formation** and can be associated with **iodine deficiency**, but not with MEN syndromes. - It usually presents as a **solitary thyroid nodule** and lacks connection with **primary hyperparathyroidism**.

Q: Which of the following is true regarding carcinoid tumor?

Neuroendocrine tumor. ### Most common site is lung - Carcinoid tumors are more commonly found in the **gastrointestinal tract**, specifically the appendix and ileum, rather than the lungs [1]. - This statement is false as they can occur in the lungs but are not the most common site overall. ### Potentially malignant tumor - Carcinoid tumors can be classified as **malignant,** especially if they show aggressive behavior or metastasis. - Many carcinoid tumors, particularly those in the gastrointestinal tract, can be **non-functional** and less aggressive [1]. ### Neuroendocrine tumor - Carcinoid tumors are indeed a type of **neuroendocrine tumor**, arising from **neuroendocrine cells**. - This classification emphasizes their origin and potential for secretion of hormones like **serotonin**. ### Associated with serotonin production - Many carcinoid tumors produce **serotonin**, leading to symptoms like **carcinoid syndrome** when they metastasize, particularly to the liver [1]. - This statement is true, indicating their involvement in neuroendocrine secretions.

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: 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 the MOST important factor determining whether a substance can be filtered at the glomerulus?

Molecular weight of the substance. ***Molecular weight of the substance*** - The **glomerular filtration barrier** acts as a size-selective filter, generally permeable to substances with a molecular weight less than 5,000-10,000 Daltons - Larger molecules are typically restricted from filtration due to the **size exclusion** property of the glomerular basement membrane and podocyte slit diaphragms - This is the **primary determinant** of whether a substance can be filtered at all, making it the most important factor among the given options *Lipid solubility of the substance* - **Lipid solubility** is more relevant for reabsorption and secretion in the renal tubules, particularly for passive diffusion across tubular cell membranes - It has minimal direct influence on the initial filtration process at the glomerulus, which is primarily a **pressure-driven, size- and charge-selective ultrafiltration** process - The glomerular capillary wall is not a lipid membrane barrier for the filtration process *Binding capacity to albumin* - Substances bound to **large plasma proteins** like albumin (molecular weight ~67,000 Daltons) cannot pass through the glomerular filtration barrier - While important for determining the *free, filterable fraction* of a substance in plasma, the binding itself is secondary to the fundamental molecular weight/size restriction - Only the **free (unbound) fraction** of a substance is available for filtration, and whether it filters depends primarily on its molecular weight *None of the options* - This option is incorrect because **molecular weight** is indeed the most critical factor among the given options for determining whether a substance can be filtered at the glomerulus

Q: Which of the following statements is true about coronary circulation?

Major flow during diastole. ***Major flow during diastole*** - The **coronary arteries** are compressed during **systole** by the contracting myocardium, significantly reducing blood flow to the heart muscle. - During **diastole**, the myocardium relaxes, allowing the coronary arteries to open fully and deliver the majority (70-80%) of oxygenated blood to the heart. - This is the most distinctive feature of coronary circulation. *Flow rate is approximately 500 ml/min* - The typical **coronary blood flow** at rest is approximately **225-250 ml/min** (about 5% of cardiac output at rest). - 500 ml/min is significantly higher than normal resting coronary flow and would represent a pathological or high-demand state. *Uniform flow during full cardiac cycle* - **Coronary blood flow** is highly variable (phasic) throughout the cardiac cycle, being significantly higher during **diastole** and much lower during **systole**. - This non-uniform flow is a unique characteristic of coronary circulation due to mechanical compression from myocardial contraction. *All of the above* - Not all statements are correct, as the flow rate value is incorrect and flow is non-uniform throughout the cardiac cycle. - The **major flow during diastole** is the most accurate and physiologically important statement regarding coronary circulation.

Q: Which of the following statements is true regarding the Bezold-Jarisch reflex?

Hypotension. ***Hypotension*** - The Bezold-Jarisch reflex is a **cardioinhibitory reflex** that is typically activated by strong ventricular contraction or noxious stimuli, leading to a triad of **bradycardia**, **peripheral vasodilation**, and subsequent **hypotension**. - This reflex is thought to be a protective mechanism to prevent excessive cardiac work or to trigger a "fainting" response to remove the body from danger. *Hypertension* - The Bezold-Jarisch reflex primarily causes a **decrease in blood pressure**, making hypertension an incorrect outcome. - Its activation directly opposes the mechanisms that would lead to increased blood pressure. *Tachycardia* - A key component of the Bezold-Jarisch reflex is **bradycardia** (slowing of the heart rate), not tachycardia. - This reflex is mediated by the vagus nerve, which primarily exerts inhibitory control over heart rate. *Hyperpnea* - The Bezold-Jarisch reflex primarily impacts **cardiovascular function** and does not directly cause hyperpnea (increased rate and depth of breathing). - While other reflexes can affect respiration, this particular reflex is not known for its respiratory effects.

Q: Where are the stretch receptors located in the left atrium?

Entrance of the pulmonary veins. ***Entrance of the pulmonary veins*** - **Stretch receptors** are mechanoreceptors that detect changes in pressure and volume. In the left atrium, they are primarily located at the **junction of the pulmonary veins and the left atrium** [1]. - These receptors play a crucial role in the **Bainbridge reflex** and the release of **atrial natriuretic peptide (ANP)** in response to increased blood volume [1]. *Atrioventricular septum* - The **atrioventricular septum** separates the atria from the ventricles and primarily contains components of the **cardiac conduction system**, such as the AV node and bundle of His [2]. - While it has specialized tissues, it is not the primary location for **stretch receptors** involved in volume sensing. *Septum between the atria* - The **interatrial septum** primarily separates the right and left atria. - Although it contains some myocardial cells, it is not the main site for **stretch receptors** responsible for monitoring left atrial volume. *None of the options* - This option is incorrect because the **entrance of the pulmonary veins** is indeed the primary location for stretch receptors in the left atrium [1].

Question 1

Which organ receives dual blood supply with both sources contributing to its primary metabolic function?

Accepted Answer

Liver

Answer

Heart

Answer

Kidney

Answer

Lung

Question 2

Which type of thyroid cancer is associated with primary hyperparathyroidism and phaeochromocytoma?

Accepted Answer

Medullary carcinoma of the thyroid

Answer

Papillary carcinoma of the thyroid

Answer

Anaplastic carcinoma of the thyroid

Answer

Follicular carcinoma of the thyroid

Question 3

Which of the following is true regarding carcinoid tumor?

Accepted Answer

Neuroendocrine tumor

Answer

Associated with serotonin production

Answer

Potentially malignant tumor

Answer

Most common site is lung

Question 4

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 5

Alkaline diuresis in drug poisoning is not done in?

Accepted Answer

Morphine

Answer

Aspirin

Answer

Phenobarbitone

Answer

Methotrexate

Question 6

Which statement best describes first-order kinetics in pharmacokinetics?

Accepted Answer

Elimination of the drug is proportional to the serum concentration

Answer

Absorption of the drug is independent of the serum concentration

Answer

Absorption of the drug is proportional to the serum concentration

Answer

Elimination of the drug is independent of the serum concentration

Question 7

Which of the following is the MOST important factor determining whether a substance can be filtered at the glomerulus?

Accepted Answer

Molecular weight of the substance

Answer

Lipid solubility of the substance

Answer

Binding capacity to albumin

Answer

None of the options

Question 8

Which of the following statements is true about coronary circulation?

Accepted Answer

Major flow during diastole

Answer

Uniform flow during full cardiac cycle

Answer

Flow rate is approximately 500 ml/min

Answer

All of the above

Question 9

Which of the following statements is true regarding the Bezold-Jarisch reflex?

Accepted Answer

Hypotension

Answer

Hypertension

Answer

Tachycardia

Answer

Hyperpnea

Question 10

Where are the stretch receptors located in the left atrium?

Accepted Answer

Entrance of the pulmonary veins

Answer

None of the options

Answer

Atrioventricular septum

Answer

Septum between the atria

NEET-PG 2015

Anatomy

Internal Medicine

Pathology

Pharmacology

Physiology