Anatomy
4 questionsWhich of the following nerves does NOT contribute to the sensory supply of the tongue?
Azygos vein drains into:
The internal anal sphincter is a part of which of the following?
Which of the following statements about the anatomy of the right ventricle is correct?
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 161: Which of the following nerves does NOT contribute to the sensory supply of the tongue?
- A. Vagus nerve
- B. None of the options
- C. Glossopharyngeal nerve
- D. Lingual nerve
Explanation: ***None of the options*** - All three nerves listed (Vagus, Glossopharyngeal, and Lingual) **DO contribute to the sensory supply of the tongue**, making this the correct answer. - Since the question asks which nerve does **NOT contribute**, and all listed nerves actually do contribute, none of them is the correct choice. *Vagus nerve* - The **vagus nerve (CN X)** provides **both general sensation and taste** to the **posterior-most part of the tongue** (base of tongue and region around vallate papillae) via the **internal laryngeal branch** of the superior laryngeal nerve [1]. - It also supplies sensory innervation to the **epiglottis and vallecula** [1]. *Glossopharyngeal nerve* - The **glossopharyngeal nerve (CN IX)** supplies both **general sensation and taste sensation** to the **posterior one-third of the tongue** [1]. - It also provides motor innervation to the **stylopharyngeus muscle** and parasympathetic innervation to the **parotid gland**. *Lingual nerve* - The **lingual nerve**, a branch of the **mandibular nerve (CN V3)**, provides **general sensation** (touch, pain, temperature) to the **anterior two-thirds of the tongue** [1]. - It also carries **taste fibers from the chorda tympani** (branch of facial nerve, CN VII) for the anterior two-thirds of the tongue [1].
Question 162: Azygos vein drains into:
- A. Right subcostal vein
- B. Right ascending lumbar vein
- C. Superior vena cava (Correct Answer)
- D. Brachiocephalic
Explanation: ***Superior vena cava*** - The **azygos vein** is a major venous channel that drains the walls of the thorax and abdomen, emptying directly into the **superior vena cava (SVC)**. [1] - This connection is crucial for venous return from the posterior thoracic wall, pericardium, and bronchi, especially bypassing the inferior vena cava if it's obstructed. [1] *Right subcostal vein* - The right subcostal vein is a tributary that helps form the **azygos vein**; it does not receive drainage from the azygos vein. - It contributes to the initial formation of the azygos system, not its termination. *Brachiocephalic* - The **brachiocephalic veins** are formed by the union of the internal jugular and subclavian veins, and they merge to form the **superior vena cava**. - The azygos vein drains into the superior vena cava, not directly into the brachiocephalic veins. *Right ascending lumbar vein* - The **right ascending lumbar vein** is a major tributary that contributes to the formation of the **azygos vein** in the lumbar region. - It drains into the azygos system, illustrating its origin rather than its termination.
Question 163: The internal anal sphincter is a part of which of the following?
- A. Puborectalis muscle
- B. Deep perineal muscles
- C. Internal longitudinal fibers
- D. Internal circular fibers (Correct Answer)
Explanation: ***Internal circular fibers*** - The **internal anal sphincter** is an involuntary muscle formed by the thickening of the **circular smooth muscle layer** of the rectum. - This sphincter maintains **tonic contraction** and is responsible for about 80% of resting anal pressure [1]. *Puborectalis muscle* - The **puborectalis muscle** is a voluntary muscle, forming a sling around the anorectal junction to maintain the **anorectal angle** [1]. - It is part of the **levator ani muscles**, which are skeletal muscles, not smooth muscle [1]. *Deep perineal muscles* - The **deep perineal muscles** are a group of skeletal muscles located in the urogenital diaphragm. - They are involved in functions such as **urinary continence** and **erection**, but do not form the internal anal sphincter. *Internal longitudinal fibers* - The **longitudinal muscle layer** of the rectum continues downwards as the conjoined longitudinal muscle, which blends with the external anal sphincter. - These fibers contribute to the **anorectal ring** and support the anal canal but do not form the internal anal sphincter itself.
Question 164: Which of the following statements about the anatomy of the right ventricle is correct?
- A. TV & PV Share fibrous continuity
- B. More prominent trabeculation
- C. The crista supraventricularis separates the tricuspid and pulmonary valves, and the apex is trabeculated (Correct Answer)
- D. All of the options
Explanation: The crista supraventricularis separates the tricuspid and pulmonary valves, and the apex is trabeculated - The **crista supraventricularis** (also known as the supraventricular crest) is a prominent muscular ridge that separates the **inflow tract** (tricuspid valve region) from the **outflow tract** (pulmonary valve region) in the right ventricle. - The **apex and trabecular portion** of the right ventricle contains prominent **trabeculae carneae**, which are irregular muscular ridges and columns. - This option is correct as it describes two key anatomical features: the structural separator between valves and the trabeculated apex. *TV & PV Share fibrous continuity* - This statement is **anatomically incorrect** for the right ventricle. - The **tricuspid valve** and **pulmonary valve** do NOT share fibrous continuity; they are separated by the **crista supraventricularis** (muscular ridge). - **Fibrous continuity** (mitral-aortic continuity) is a characteristic feature of the **left heart**, where the anterior mitral leaflet is continuous with the aortic valve, but this does NOT occur in the right ventricle. *More prominent trabeculation* - While this statement is **anatomically true** (the right ventricle has more prominent trabeculation than the left ventricle, which has a smoother wall), this option is **incomplete** when compared to the correct answer. - The question asks for the correct statement about right ventricle anatomy, and option 3 provides a **more comprehensive description** that includes both a unique structural landmark (crista supraventricularis) and the trabeculation feature. - In single-best-answer format, the most complete and specific option is preferred. *All of the options* - This option is incorrect because the statement "TV & PV Share fibrous continuity" is anatomically false. - Since not all options are correct, this cannot be the answer.
Biochemistry
1 questionsConverging point of both pathways in coagulation is at:
NEET-PG 2015 - Biochemistry NEET-PG Practice Questions and MCQs
Question 161: Converging point of both pathways in coagulation is at:
- A. Factor VIII
- B. Stuart factor X (Correct Answer)
- C. Factor IX
- D. Factor VII
Explanation: ***Stuart factor X*** [1][2] - It is the main **converging point** of the coagulation cascade, where both the intrinsic and extrinsic pathways meet to initiate the common pathway [1]. - Activated factor X leads to the conversion of **prothrombin to thrombin**, pivotal for clot formation [2]. *Factor VII* [2] - Primarily involved in the **extrinsic pathway** of coagulation, activating factor X, but does not serve as a converging point. - Its function is limited to starting the coagulation cascade, particularly upon tissue injury. *Factor IX* [2] - A key component of the **intrinsic pathway**, it leads to the activation of factor X but is not the point where both pathways converge. - It requires **factor VIII** for its activation, further illustrating its role within a specific pathway. *Factor VIII* - Also part of the **intrinsic pathway**, it acts as a cofactor for factor IX but does not integrate both pathways into a common point. - Its deficiency is associated with **Hemophilia A**, underscoring its specific pathway involvement. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 128-130. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 582-583.
Internal Medicine
1 questionsWhich type of thyroid cancer is associated with primary hyperparathyroidism and phaeochromocytoma?
NEET-PG 2015 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 161: 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**.
Orthopaedics
1 questionsWhich ligament is most commonly damaged in knee injuries?
NEET-PG 2015 - Orthopaedics NEET-PG Practice Questions and MCQs
Question 161: Which ligament is most commonly damaged in knee injuries?
- A. PCL
- B. LCL
- C. MCL
- D. ACL (Correct Answer)
Explanation: ***ACL*** - The **anterior cruciate ligament (ACL)** is highly susceptible to injury, especially during sports involving sudden stops, changes in direction, jumping, and awkward landings. - Its role in stabilizing the knee against **anterior tibial translation** and rotational forces makes it vulnerable to tears. *PCL* - The **posterior cruciate ligament (PCL)** is much stronger than the ACL and less frequently injured, typically requiring a direct blow to the flexed knee (e.g., dashboard injury). - It prevents **posterior tibial translation** relative to the femur. *MCL* - The **medial collateral ligament (MCL)** is commonly injured, often due to a direct blow to the outside of the knee causing a **valgus stress**. - While frequently damaged, it is often injured in conjunction with the ACL but the ACL is more frequently injured in isolation. *LCL* - The **lateral collateral ligament (LCL)** is the least commonly injured of the four major knee ligaments. - It usually results from a direct blow to the inside of the knee causing **varus stress**.
Pharmacology
1 questionsAlkaline diuresis in drug poisoning is not done in?
NEET-PG 2015 - Pharmacology NEET-PG Practice Questions and MCQs
Question 161: Alkaline diuresis in drug poisoning is not done in?
- A. Aspirin
- B. Morphine (Correct Answer)
- C. Phenobarbitone
- D. Methotrexate
Explanation: ***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.
Physiology
1 questionsPenile erection is mediated by which system?
NEET-PG 2015 - Physiology NEET-PG Practice Questions and MCQs
Question 161: Penile erection is mediated by which system?
- A. Parasympathetic system via muscarinic receptors (Correct Answer)
- B. Parasympathetic system via nicotinic receptors
- C. Sympathetic system via α-receptors
- D. Sympathetic system via β-receptors
Explanation: ***Parasympathetic system via muscarinic receptors*** - Penile erection is primarily a **parasympathetic response** mediated by the **pelvic splanchnic nerves (S2-S4)**. - The key mechanism involves **nitric oxide (NO)** release from non-adrenergic, non-cholinergic (NANC) neurons, which activates guanylate cyclase → increases cGMP → smooth muscle relaxation in the **corpora cavernosa**. - **Acetylcholine acting on muscarinic receptors** plays a **supportive role** by enhancing NO release and contributing to vasodilation. - For exam purposes, the parasympathetic system (with its cholinergic muscarinic component) is the recognized answer. *Parasympathetic system via nicotinic receptors* - **Nicotinic receptors** are located at **autonomic ganglia** and **neuromuscular junctions**, not at the effector sites in penile vasculature. - While nicotinic transmission occurs at the parasympathetic ganglia, the post-ganglionic fibers act on **muscarinic receptors** and release **NO** at the target tissue. - This option confuses the ganglionic transmission with the effector mechanism. *Sympathetic system via α-receptors* - The **sympathetic nervous system** via **α1-adrenergic receptors** causes **vasoconstriction** and maintains penile **flaccidity** (detumescence). - Sympathetic activation is responsible for **ejaculation** and the resolution phase after orgasm. - Activation of α-receptors opposes erection by causing smooth muscle contraction. *Sympathetic system via β-receptors* - **β-adrenergic receptors** are involved in functions like **cardiac stimulation** and **bronchodilation**, but play no significant role in penile erection. - The sympathetic system's role in sexual function is primarily through **α-receptors** (detumescence and ejaculation), not β-receptors.
Psychiatry
1 questionsThe delusion that involves the belief that a familiar person has been replaced by someone else is known as?
NEET-PG 2015 - Psychiatry NEET-PG Practice Questions and MCQs
Question 161: The delusion that involves the belief that a familiar person has been replaced by someone else is known as?
- A. Capgras syndrome (Correct Answer)
- B. Cotard syndrome
- C. Othello syndrome
- D. Fregoli syndrome
Explanation: ***Capgras syndrome*** - This **delusional misidentification syndrome** is characterized by the belief that a familiar person (e.g., a spouse, child, or parent) has been replaced by an identical imposter. - It often occurs in individuals with **schizophrenia**, **dementia**, or following **brain injury**. *Cotard syndrome* - This syndrome involves a nihilistic delusion where the individual believes they are **dead**, do not exist, or have lost their organs or blood. - It is often associated with severe **depression**, psychosis, or neurological disorders. *Othello syndrome* - Also known as **delusional jealousy**, this involves the unfounded belief that one's partner is being unfaithful. - It is a **primary delusional disorder** but can also be seen in conditions like alcohol dependence or neurodegenerative diseases. *Fregoli syndrome* - This is another **delusional misidentification syndrome** where the person believes that different people are actually the same person in disguise. - It is the opposite of Capgras syndrome and may occur in **schizophrenia** or **organic brain disorders**.