Anatomy
1 questionsWhich type of glial cell is derived from mesodermal origin?
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 421: Which type of glial cell is derived from mesodermal origin?
- A. Macroglial cells
- B. Microglial cells (Correct Answer)
- C. Oligodendrocytes
- D. Ependymal cells
Explanation: ***Microglial cells*** - **Microglial cells** are unique among glial cells as they originate from **mesoderm**, specifically from **monocyte/macrophage precursors** in the bone marrow [1]. - They function as the **immune cells of the central nervous system (CNS)**, scavenging for plaques, damaged neurons, and infectious agents [1]. *Macroglial cells* - This is a broad category that includes **astrocytes, oligodendrocytes, and ependymal cells**, all of which are derived from **neuroectoderm**, not mesoderm [1]. - They perform various supportive roles but are distinct in origin from microglial cells [1]. *Oligodendrocytes* - **Oligodendrocytes** are derived from **neuroectoderm** and are responsible for forming the **myelin sheath** around axons in the CNS [2]. - Myelination is crucial for rapid and efficient nerve impulse conduction. *Ependymal cells* - **Ependymal cells** are derived from **neuroectoderm** and line the **ventricles of the brain** and the **central canal of the spinal cord**. - They play a role in the production and circulation of **cerebrospinal fluid (CSF)**.
Biochemistry
2 questionsWhat primarily forms the core of chylomicrons?
Transport of lipids from the intestine to other tissues is by -
NEET-PG 2015 - Biochemistry NEET-PG Practice Questions and MCQs
Question 421: What primarily forms the core of chylomicrons?
- A. Triglycerides and Cholesterol together
- B. Triglycerides (Correct Answer)
- C. Free fatty acids
- D. Triglyceride, Cholesterol and Phospholipids
Explanation: ***Triglycerides*** - Chylomicrons are primarily responsible for transporting **dietary triglycerides** from the intestines to other tissues. - Their large core, composed mainly of **triglycerides**, allows efficient transport of these hydrophobic molecules. *Triglycerides and Cholesterol together* - While **cholesterol** is present in chylomicrons, it is less abundant than **triglycerides** and primarily exists as **cholesterol esters** in the core. - The core is not an equal mixture; **triglycerides** overwhelmingly dominate the volume. *Free fatty acids* - **Free fatty acids** are transported in the blood primarily bound to **albumin**, not within the core of chylomicrons. - Chylomicrons typically carry **esterified fatty acids** as part of triglycerides. *Triglyceride, Cholesterol and Phospholipids* - **Phospholipids** form the outer monolayer of the chylomicron, along with apoproteins, making them **amphipathic**. - They do not constitute a core component but rather the **surface interface** with the aqueous environment.
Question 422: Transport of lipids from the intestine to other tissues is by -
- A. Chylomicrons (Correct Answer)
- B. LDL
- C. HDL
- D. VLDL
Explanation: ***Chylomicrons*** - **Chylomicrons** are the **largest lipoprotein particles** that transport **dietary (exogenous) lipids** from the **intestine** to peripheral tissues - They are synthesized in **intestinal enterocytes** after fat absorption and enter the bloodstream via the **lymphatic system (thoracic duct)** - They carry **triglycerides (85-95%), cholesterol, phospholipids, and fat-soluble vitamins** (A, D, E, K) - **Apolipoprotein B-48** is the characteristic structural protein of chylomicrons - After delivering triglycerides to tissues (via lipoprotein lipase), chylomicron remnants are taken up by the **liver** *LDL (Low-Density Lipoprotein)* - LDL transports **cholesterol from the liver to peripheral tissues** (not from intestine) - It carries **endogenous cholesterol**, not dietary lipids from the intestine - Often called "**bad cholesterol**" due to its role in atherosclerosis - Contains **Apolipoprotein B-100** *HDL (High-Density Lipoprotein)* - HDL performs **reverse cholesterol transport** - moving excess cholesterol from peripheral tissues **back to the liver** - It does **not transport lipids from the intestine** to tissues - Called "**good cholesterol**" for its protective cardiovascular role - Contains **Apolipoprotein A-I and A-II** *VLDL (Very-Low-Density Lipoprotein)* - VLDL is synthesized in the **liver** (not intestine) and transports **endogenous triglycerides** to peripheral tissues - It carries lipids **from the liver**, not from the intestine - VLDL is converted to IDL and then LDL after losing triglycerides - Contains **Apolipoprotein B-100**
Internal Medicine
2 questionsWhich type of thyroid cancer is associated with primary hyperparathyroidism and phaeochromocytoma?
Which of the following is not a feature of Poststreptococcal Glomerulonephritis (PSGN)?
NEET-PG 2015 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 421: Which type of thyroid cancer is associated with primary hyperparathyroidism and phaeochromocytoma?
- A. Medullary carcinoma of the thyroid (Correct Answer)
- B. Papillary carcinoma of the thyroid
- C. Anaplastic carcinoma of the thyroid
- D. Follicular carcinoma of the thyroid
Explanation: ***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**.
Question 422: Which of the following is not a feature of Poststreptococcal Glomerulonephritis (PSGN)?
- A. HTN
- B. Increased urea
- C. Increased creatinine
- D. Normal C3 level (Correct Answer)
Explanation: ***Normal C3 level*** - In Post-streptococcal glomerulonephritis (PSGN), **C3 levels are typically decreased** due to complement consumption during the inflammatory process. [1] - A **normal C3 level** would not be consistent with PSGN, as it suggests no significant complement activation. *Increased urea* - Increased urea can occur due to **impaired renal function**, which is common in PSGN due to glomerular inflammation. [1] - It's a typical finding reflecting the kidneys' inability to excrete waste products properly. *HTN* - Hypertension is frequently associated with PSGN due to **volume overload** and activation of the renin-angiotensin system. [1] [2] - It is a common clinical feature that results from increased fluid retention. *Increased creatinine* - Increased creatinine levels indicate **renal impairment**, which is characteristic of PSGN as kidney function is affected during this condition. [1] - This finding highlights the reduction in glomerular filtration rate (GFR), typical in glomerulonephritis. [2]
Pathology
5 questionsWhich histological type of lung cancer is most commonly associated with metastasis?
Most common type of renal carcinoma is:
IgA nephropathy is not associated with which of the following?
Irregular scarred kidney with pelvic dilatation is seen with?
Fibrosis associated with liver cirrhosis is mediated by -
NEET-PG 2015 - Pathology NEET-PG Practice Questions and MCQs
Question 421: Which histological type of lung cancer is most commonly associated with metastasis?
- A. Small cell carcinoma (Correct Answer)
- B. Squamous cell carcinoma
- C. Adenocarcinoma
- D. Large cell carcinoma
Explanation: ***Squamous cell CA*** - Known for its **aggressive nature** and propensity to metastasize, particularly in later stages. - Typically arises in the **central part of the lungs**, often associated with smoking and leads to local invasion and distant spread. *Alveolar-carcinoma* - Rarely found and tends to be **less aggressive** compared to squamous cell carcinoma. - Usually has a more localized effect without the same potential for widespread metastasis. *Small cell carcinoma* - Although it is **highly metastatic**, it is less common than squamous cell carcinoma in terms of overall lung cancer incidence. - Characterized by its rapid growth and early metastasis [1], but mostly associated with a specific subtype of lung cancer cases. *Adenocarcinoma* - Generally presents as a **peripheral lung lesion** and has **less propensity for early metastasis** compared to squamous cell carcinoma. - More common in non-smokers and tends to have a less aggressive metastatic pattern. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 337-338.
Question 422: Most common type of renal carcinoma is:
- A. Clear cell type (Correct Answer)
- B. Chromophobe type
- C. Papillary type
- D. Collecting duct type
Explanation: ***Clear cell type*** - The **clear cell type** is the most common subtype of renal carcinoma, constituting about **70-80%** of cases [3]. - It is typically associated with **von Hippel-Lindau syndrome** and presents with clear or "foamy" cells due to lipid accumulation [3]. *Chromophobe type* - This type comprises about **5-10%** of renal cell carcinomas and usually has a better prognosis [1]. - Characterized by **pale cells with distinct cell borders** and lacks the common features of clear cell carcinoma [1]. *Tubular type* - The tubular variant is less common and does not represent a major subtype of renal cell carcinoma. - It is often confused with other variants but lacks the distinct characteristics of the clear cell type. *Papillary type* - The papillary type accounts for about **10-15%** of renal carcinomas and is characterized by papillary structures [2]. - This type generally has a distinct chromosomal mutation profile compared to the clear cell type [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, p. 959. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 958-959. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 959-961.
Question 423: IgA nephropathy is not associated with which of the following?
- A. Focal mesangial proliferation
- B. Gross hematuria concurrent with upper respiratory infection
- C. Immunofluorescence deposits contain IgA and IgG
- D. Decreased complement level (Correct Answer)
Explanation: ***Decreased complement level*** - IgA nephropathy is typically associated with **normal serum complement levels** (C3 and C4), which is an important distinguishing feature. - Unlike post-streptococcal glomerulonephritis or lupus nephritis where complement levels are **low/decreased**, IgA nephropathy does not cause systemic complement consumption. - While complement activation does occur locally in the glomerulus (via lectin and alternative pathways), it does not lead to a decrease in serum complement levels. *Focal mesangial proliferation* - This is a **common histological finding** in IgA nephropathy, reflecting the proliferative response to IgA deposition in the mesangium. - The mesangial cells proliferate in an attempt to clear the immune deposits. *Gross hematuria concurrent with upper respiratory infection* - This is a **classic clinical presentation** of IgA nephropathy, often referred to as **synpharyngitic hematuria**. - The episode of gross hematuria typically occurs **within 1-2 days** of the onset of an upper respiratory tract infection, distinguishing it from post-streptococcal glomerulonephritis where hematuria appears 1-3 weeks later. *Immunofluorescence deposits contain IgA and IgG* - The defining feature of IgA nephropathy on immunofluorescence is the **predominant deposition of IgA**, often accompanied by C3. - While IgA is the primary immunoglobulin, **IgG and IgM can also be present** in variable amounts, but IgA must be the dominant or co-dominant immunoglobulin for the diagnosis.
Question 424: Irregular scarred kidney with pelvic dilatation is seen with?
- A. Chronic pyelonephritis (Correct Answer)
- B. Polycystic kidney
- C. Renal artery stenosis
- D. Tuberculosis of kidney
Explanation: ***Chronic pyelonephritis*** - Characterized by irregular scarring of the kidney and often leads to **pelvic dilatation** due to recurrent infections and obstruction [1]. - The damage from inflammation results in **cortical scarring** and can affect kidney function significantly over time [1]. *Renal artery stenosis* - Typically presents with **hypertension** and may lead to ischemic atrophy, but does not cause significant **pelvic dilatation**. - The kidney appears small and often asymmetric, but not typically irregular and scarred. *Tuberculosis of kidney* - Can cause damage to the kidney, but usually leads to **caseating granulomas** and can cause abscesses, not specifically irregular scarring with pelvic dilation. - Often presents with systemic symptoms such as fever and night sweats, along with hematuria. *Polycystic kidney* - Characterized by multiple cysts in both kidneys leading to enlarged kidneys, but does not typically present as **irregularly scarred kidneys**. - Usually associated with **hemodynamic issues** and hypertension but not pelvic dilatation in the sense of scarring or fibrosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 937-939.
Question 425: Fibrosis associated with liver cirrhosis is mediated by -
- A. Platelet-Derived Growth Factor (PDGF)
- B. Transforming Growth Factor-beta (TGF-β) (Correct Answer)
- C. Vascular Endothelial Growth Factor (VEGF)
- D. Tumor Necrosis Factor-alpha (TNF-α)
Explanation: ***PDGF*** - Platelet-Derived Growth Factor (**PDGF**) is a critical mediator in the **fibrogenic response** associated with liver cirrhosis [1]. - It stimulates the **proliferation** and activation of hepatic stellate cells, leading to excessive **collagen deposition** and fibrosis [1][2]. *ICAM-1* - Intercellular Adhesion Molecule-1 (**ICAM-1**) primarily mediates **cell adhesion** and is involved in inflammatory processes, not directly in fibrosis. - While it may play a role in **leukocyte recruitment**, it does not contribute significantly to the fibrogenic pathway in liver cirrhosis. *PcAM-l* - **PCAM-1** (Platelet/endothelial cell adhesion molecule-1) is involved in **cell adhesion** and is primarily expressed on endothelial cells. - Its role is more associated with **angiogenesis** and inflammation, lacking direct involvement in the fibrogenic process of cirrhosis. *IFN-y* - Interferon-gamma (**IFN-y**) is a cytokine that predominantly has a role in **immune modulation** and does not directly induce fibroblast activation. - It may have regulatory effects on inflammation but does not lead to significant fibrosis associated with liver cirrhosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 31-32. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 830-832.