Anatomy
2 questionsElastic fibers of tunica media are secreted by
Sertoli cells are derived from -
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 431: Elastic fibers of tunica media are secreted by
- A. Endothelium
- B. Smooth muscle (Correct Answer)
- C. External lamina
- D. Fibroblast
Explanation: Correct: Smooth muscle - Smooth muscle cells within the tunica media are primarily responsible for synthesizing and secreting elastic fibers along with collagen and proteoglycans [1] - This extracellular matrix provides elasticity and structural integrity to blood vessels, allowing them to stretch and recoil with blood flow [1] - In elastic arteries (like the aorta), smooth muscle cells produce fenestrated elastic membranes that are characteristic of the tunica media Incorrect: Endothelium - Endothelial cells form the innermost lining of blood vessels (tunica intima) and are involved in regulating vascular tone, blood clotting, and inflammation [1] - They do not typically secrete the bulk of elastic fibers found in the tunica media Incorrect: External lamina - The external lamina (or external basal lamina) is an extracellular matrix layer, not a cellular component that secretes elastic fibers - It is actually secreted by the smooth muscle cells themselves and serves as structural support around individual muscle cells Incorrect: Fibroblast - Fibroblasts are connective tissue cells that primarily produce collagen and other extracellular matrix components in many tissues - While they contribute to the tunica adventitia (outermost layer), the tunica media's elastic fibers are primarily produced by smooth muscle cells [1]
Question 432: Sertoli cells are derived from -
- A. Genital swelling
- B. Coelomic epithelium (Correct Answer)
- C. Primordial germ cells
- D. Germinal epithelium
Explanation: Sertoli cells are derived from the **coelomic epithelium** (surface epithelium) of the urogenital ridge during gonadal development. - The coelomic epithelium proliferates to form the **primitive sex cords** (medullary cords in males), and cells within these cords differentiate into Sertoli cells. - These cells are essential for **spermatogenesis**, providing structural support and nutrition to developing germ cells, and producing **anti-Müllerian hormone (AMH)** which causes regression of Müllerian ducts in male development [1]. *Germinal epithelium* - This is an **outdated term** previously used for the surface epithelium of the gonad, based on the misconception that it gave rise to germ cells. - Modern embryology uses the term **coelomic epithelium** or surface epithelium instead. - While historically used, this terminology is no longer preferred in current medical literature. *Genital swelling* - **Genital swellings** (labioscrotal swellings) are external mesodermal structures that develop into the **scrotum** in males or **labia majora** in females. - These are external genitalia components and are not the source of internal testicular cells like Sertoli cells. *Primordial germ cells* - **Primordial germ cells (PGCs)** originate from the epiblast, migrate via the hindgut to the developing gonads, and differentiate into **spermatogonia** (males) or **oogonia** (females) [1]. - They form the **germ cell lineage** (gametes), not somatic support cells like Sertoli cells, which are of coelomic epithelial origin.
Biochemistry
1 questionsLevel of which of the following is not elevated in heart disease
NEET-PG 2015 - Biochemistry NEET-PG Practice Questions and MCQs
Question 431: Level of which of the following is not elevated in heart disease
- A. SGOT
- B. ALP
- C. LDH
- D. 5-nucleotidase (Correct Answer)
Explanation: ***5-nucleotidase*** - While other enzymes like LDH, SGOT, and ALP can be elevated in various conditions including heart disease (especially in the context of tissue damage), 5-nucleotidase is **not typically elevated in heart disease**. - Its elevation is more commonly associated with **biliary obstruction** or certain liver pathologies. *LDH* - **Lactate dehydrogenase (LDH)** is a marker of **cellular damage** and can be elevated in myocardial infarction, though it is less specific than troponins. - LDH levels rise later than CK-MB and remain elevated longer, indicating persistent tissue injury. *SGOT* - **Serum glutamic oxaloacetic transaminase (SGOT)**, also known as **aspartate aminotransferase (AST)**, is elevated in acute **myocardial infarction** due to cardiac muscle damage. - While it's a marker for cardiac injury, it's not specific as it's also highly concentrated in the liver. *ALP* - **Alkaline phosphatase (ALP)** can be mildly elevated in heart failure due to **hepatic congestion** caused by reduced cardiac output. - While its primary diagnostic significance is in bone and liver disease, its elevation in advanced heart disease is usually a secondary consequence.
Community Medicine
1 questionsThe strongest occupational risk factor for hematological carcinoma is
NEET-PG 2015 - Community Medicine NEET-PG Practice Questions and MCQs
Question 431: The strongest occupational risk factor for hematological carcinoma is
- A. Benzene (Correct Answer)
- B. Lithium
- C. Radiation exposure
- D. Cigarette smoke
Explanation: ***Benzene*** - Benzene exposure is recognized as a potent **carcinogen** linked to various hematological malignancies, including **leukemia** [1]. - It affects the **bone marrow**, leading to dysplastic changes and ultimately malignancy. *Nicotine* - Although nicotine is associated with **smoking-related cancers**, it is not directly linked to **hematological carcinomas**. - Its primary role is in causing **lung cancer**, rather than blood cancers. *Lithium* - Lithium is primarily used for **bipolar disorder** and does not have a known link to causing hematological malignancies. - Side effects are more related to **nephrotoxicity** rather than carcinogenic effects. *Alcohol* - Alcohol consumption is primarily associated with **liver cancers** and not specifically linked to hematological carcinomas [2]. - It can contribute to general malignancy development but is not a direct cause of blood cancers. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, p. 286. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 217-218.
Internal Medicine
1 questionsMajor contribution to cachexia with advanced cancer?
NEET-PG 2015 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 431: Major contribution to cachexia with advanced cancer?
- A. Tumor-necrosis-factor (TNF) (Correct Answer)
- B. Histamine
- C. Interferon
- D. Clathrin
Explanation: ***Tumor-necrosis-factor (TNF)*** - **Tumor necrosis factor (TNF-α)** is a prominent cytokine involved in the pathogenesis of cancer cachexia, leading to muscle wasting and weight loss [1]. - It induces inflammation, increases **catabolism**, and reduces anabolism, contributing significantly to the metabolic dysfunction seen in cancer patients [1]. *Histamine* - **Histamine** is primarily known for its role in allergic reactions and inflammatory responses, but it is not a major direct driver of cachexia. - While it can be released in various inflammatory conditions, its direct contribution to the severe muscle wasting and metabolic changes of cachexia is limited compared to other cytokines. *Interferon* - **Interferons (IFNs)** are cytokines typically associated with antiviral responses and immune modulation, which can have diverse effects on metabolism. - While some interferons can indirectly contribute to systemic inflammation and fatigue, they are not considered a primary or major direct mediator of muscle catabolism and fat loss characteristic of cancer cachexia. *Clathrin* - **Clathrin** is a protein involved in the formation of clathrin-coated vesicles, essential for **endocytosis** and intracellular trafficking. - It has no direct role in the systemic metabolic dysregulation or muscle wasting associated with cancer cachexia.
Pathology
1 questionsCarcinoma originating from glands is called?
NEET-PG 2015 - Pathology NEET-PG Practice Questions and MCQs
Question 431: Carcinoma originating from glands is called?
- A. Basal cell carcinoma
- B. Squamous cell carcinoma
- C. Adenocarcinoma (Correct Answer)
- D. Fibrosarcoma
Explanation: ***Adenocarcinoma*** - Carcinoma that arises from **glandular epithelium** is specifically classified as adenocarcinoma [1]. - It often presents in organs like the **breast**, **prostate**, and **gastrointestinal tract** [4,5]. *Fibrosarcoma* - This is a **malignant tumor** derived from **fibrous connective tissue**, not glands. - Typically occurs in **soft tissues**, and is distinct from epithelial tumors like adenocarcinoma. *Squamous cell carcinoma* - Originates from **squamous epithelial cells** and primarily affects areas such as the **skin** and **mucous membranes** [2]. - It is not associated with glandular structures, differing markedly from adenocarcinoma. *Basal cell carcinoma* - Arises from **basal cells** in the **epidermis** (skin), not from glandular tissue. - It is the most common type of skin cancer and is largely not relevant to glandular origin. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 335-336. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 336-337. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 777-778. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 348-349.
Pharmacology
3 questionsWhich of the following conditions is not associated with an increased risk of neuropathy caused by Isoniazid (INH)?
Idoxuridine is used for treatment of?
What is the classification of Lorcaserin?
NEET-PG 2015 - Pharmacology NEET-PG Practice Questions and MCQs
Question 431: Which of the following conditions is not associated with an increased risk of neuropathy caused by Isoniazid (INH)?
- A. Uremia
- B. Diabetes mellitus
- C. Poor nutrition
- D. Hyperthyroidism (Correct Answer)
Explanation: ***Hyperthyroidism*** - **Hyperthyroidism** is not typically associated with an increased risk of isoniazid-induced neuropathy. The neuropathy due to INH is primarily linked to **pyridoxine (vitamin B6) deficiency**. - While hyperthyroidism can cause its own set of neurological symptoms, it does not directly impair pyridoxine metabolism or exacerbate INH's neurotoxic effects. *Uremia* - **Uremia** (renal failure) can increase the risk of INH-induced neuropathy due to impaired drug excretion, leading to higher plasma concentrations of INH and its metabolites. - Patients with uremia often have compromised nutritional status and may experience vitamin deficiencies, further contributing to pyridoxine depletion. *Diabetes mellitus* - **Diabetes mellitus** is a significant risk factor for INH-induced neuropathy because it is an independent cause of **peripheral neuropathy** itself, making patients more susceptible to additional nerve damage. - Diabetic patients may also have altered pyridoxine metabolism or suboptimal nutritional intake, predisposing them to INH toxicity. *Poor nutrition* - **Poor nutrition**, particularly malabsorption or inadequate dietary intake, directly contributes to **pyridoxine (vitamin B6) deficiency**. - Isoniazid's mechanism of neurotoxicity involves interfering with pyridoxine metabolism, so pre-existing deficiency significantly increases the risk of neuropathy.
Question 432: Idoxuridine is used for treatment of?
- A. Influenza
- B. RSV
- C. HSV (Correct Answer)
- D. HIV
Explanation: ***HSV*** - **Idoxuridine** is a **pyrimidine analog** that inhibits viral DNA synthesis, making it effective against **herpes simplex virus (HSV)** infections, particularly **herpes keratitis** (ophthalmic use). - Its mechanism involves being incorporated into viral DNA, leading to errors in replication and transcription. - It is applied **topically** for ocular HSV infections due to systemic toxicity concerns. *Influenza* - **Idoxuridine** is not active against **influenza viruses**. - **Antiviral drugs** like **oseltamivir** or **zanamivir** are typically used for influenza treatment. *RSV* - **Idoxuridine** is not indicated for the treatment of **respiratory syncytial virus (RSV)**. - **Ribavirin** is the primary antiviral agent used for severe RSV infections, especially in immunocompromised patients. *HIV* - **Idoxuridine** has no significant activity against **human immunodeficiency virus (HIV)**. - **Antiretroviral therapy (ART)**, a combination of drugs targeting various stages of the HIV life cycle, is used for HIV treatment.
Question 433: What is the classification of Lorcaserin?
- A. Anti-anxiety
- B. Anti-smoking
- C. Anti-helminthic
- D. Anti-obesity (Correct Answer)
Explanation: ***Anti-obesity*** - Lorcaserin is a selective **serotonin 5-HT₂C receptor agonist** that works by promoting satiety and reducing food intake. - It is prescribed as a long-term treatment for **weight management** in adults who are obese or overweight with at least one weight-related comorbidity. *Anti-anxiety* - Anti-anxiety medications, such as **benzodiazepines** or **SSRIs**, primarily target neurotransmitters like GABA or serotonin 5-HT₁A receptors to reduce anxiety symptoms. - Lorcaserin's primary mechanism of action is distinct, focusing on the 5-HT₂C receptor for appetite regulation, not anxiety. *Anti-smoking* - Anti-smoking medications, like **varenicline** or **bupropion**, are designed to reduce nicotine cravings and withdrawal symptoms. - Their mechanisms often involve nicotinic acetylcholine receptors or dopamine and norepinephrine reuptake inhibition, which differs from lorcaserin's action. *Anti-helminthic* - Anti-helminthic drugs are used to treat **parasitic worm infections** by paralyzing or killing the worms. - Common examples include **albendazole** or **mebendazole**, which have no relation to appetite control or obesity treatment.
Physiology
1 questionsLower esophageal sphincter pressure is increased by all of the following substances, EXCEPT:
NEET-PG 2015 - Physiology NEET-PG Practice Questions and MCQs
Question 431: Lower esophageal sphincter pressure is increased by all of the following substances, EXCEPT:
- A. Motilin
- B. Gastrin
- C. Substance P
- D. Secretin (Correct Answer)
Explanation: ***Secretin*** - **Secretin** is a gastrointestinal hormone that *decreases* lower esophageal sphincter (LES) pressure - This hormone is released from S cells in the duodenum in response to acidic chyme - Its primary role is to stimulate the pancreas to release **bicarbonate-rich fluid** to neutralize acidic chyme entering the duodenum - By decreasing LES pressure, it facilitates the passage of gastric contents into the duodenum during digestion *Gastrin* - **Gastrin** is a hormone that *increases* lower esophageal sphincter (LES) pressure - This helps prevent gastroesophageal reflux when the stomach is distended - It also stimulates the secretion of **gastric acid** by parietal cells in the stomach - Released from G cells in the gastric antrum in response to protein ingestion *Motilin* - **Motilin** is a peptide hormone that *increases* lower esophageal sphincter (LES) pressure - It initiates the **migrating motor complex (MMC)** during the interdigestive period - Stimulates gastric and intestinal motility - Released from M cells in the duodenum and jejunum *Substance P* - **Substance P** is a neuropeptide that *increases* lower esophageal sphincter (LES) pressure - Functions as both a neurotransmitter and neuromodulator in the enteric nervous system - Plays a role in **smooth muscle contraction** and gastrointestinal motility - Also involved in pain transmission and inflammatory responses