Anatomy
6 questionsLine from midinguinal point to adductor tubercle represents?
Esophagus is present in which mediastinum?
Which part of the heart is located in the anterosuperior sternal region?
What is the approximate ratio of connective tissue to smooth muscle in the cervix?
Helicine arteries are branches of which artery?
Which of the following statements about the great saphenous vein is true?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 131: Line from midinguinal point to adductor tubercle represents?
- A. Inferior epigastric artery
- B. Femoral artery (Correct Answer)
- C. Superior epigastric artery
- D. None of the options
Explanation: The line from the **midinguinal point** to the **adductor tubercle** accurately maps the anatomical course of the **femoral artery** in the thigh. This anatomical landmark is crucial for palpating the **femoral pulse** and locating the artery for clinical procedures like catheter insertion. *Inferior epigastric artery* - The **inferior epigastric artery** originates from the external iliac artery and ascends superiorly in the anterior abdominal wall [1]. - Its course is significantly more medial and superior, far from the line described. *Superior epigastric artery* - The **superior epigastric artery** is a terminal branch of the internal thoracic artery, descending into the rectus sheath in the upper abdomen [1]. - Its location is entirely within the anterior abdominal wall, high above the inguinal region. *None of the options* - This option is incorrect because the line from the midinguinal point to the adductor tubercle clearly represents the anatomical course of the femoral artery. - The other arteries listed are not found along this specific anatomical path.
Question 132: Esophagus is present in which mediastinum?
- A. Anterior
- B. Posterior (Correct Answer)
- C. Middle
- D. Superior
Explanation: ***Posterior*** - The **esophagus** is primarily located in the **posterior mediastinum**, where the bulk of its length (from T4/T5 to T10) traverses [2]. - It lies **posterior** to the **trachea** and **heart**, anterior to the vertebral column [2]. - For examination purposes, the esophagus is considered a **key structure of the posterior mediastinum** [2]. - Note: The uppermost part (cervical and upper thoracic) does pass through the superior mediastinum, but the majority lies in the posterior compartment. *Anterior* - The **anterior mediastinum** is a small space located between the **sternum** and the pericardium. - It primarily contains **connective tissue**, remnants of the thymus, lymph nodes, and the internal thoracic vessels [1]. - The esophagus does not traverse this compartment. *Middle* - The **middle mediastinum** is centrally located and prominently contains the **heart** and the roots of the great vessels [1]. - It also houses the **pericardium**, the main bronchi, and the phrenic nerves [1]. - The esophagus passes **posterior** to this compartment, not through it. *Superior* - The **superior mediastinum** extends from the thoracic inlet to the level of the sternal angle (T4/T5). - It contains large vessels like the **aortic arch** and its branches, the SVC, trachea, and thymus [1]. - While the **uppermost part of the thoracic esophagus** does pass through the superior mediastinum, this represents only a small portion of its total length.
Question 133: Which part of the heart is located in the anterosuperior sternal region?
- A. Right atrium and auricle.
- B. Left atrium.
- C. Left ventricle.
- D. Right ventricle. (Correct Answer)
Explanation: ***Right ventricle*** - The **right ventricle** forms the **most anterior part of the heart**, located directly behind the sternum and costal cartilages [1]. - Its position explains why **sternal precordial leads** (e.g., V1, V2) on an ECG primarily reflect right ventricular activity [1]. *Right atrium and auricle* - While part of the right atrium is anterior, the **right ventricle is significantly more anterior** and occupies the majority of the anterosuperior sternal region [1]. - The **right auricle** is a small, anterior appendage, but the broader chamber occupying this region is the ventricle [1]. *Left atrium* - The **left atrium** is the **most posterior chamber of the heart**, forming the base [1]. - It lies near the esophagus, making it susceptible to compression by an enlarged left atrium. *Left ventricle* - The **left ventricle** forms the **apex of the heart** and is located primarily on the **left and inferior** aspects. - It is not the most anterior structure; the right ventricle is positioned anteriorly to it [1].
Question 134: What is the approximate ratio of connective tissue to smooth muscle in the cervix?
- A. 2:1
- B. 5:1
- C. 15:1
- D. Approximately 8:1 (Correct Answer)
Explanation: ***Approximately 8:1*** - The **cervix** is predominantly composed of **fibrous connective tissue**, which provides its structural integrity and rigidity [1]. - This high ratio of **collagenous connective tissue** to smooth muscle is crucial for maintaining pregnancy and undergoing significant remodeling during parturition [1]. - The approximate ratio is **8:1 to 10:1**, with connective tissue forming about 85-90% of cervical tissue [1]. *2:1* - This ratio would imply a significantly higher proportion of **smooth muscle** (33%), making the cervix much more muscular and less fibrous than it actually is. - Such a composition would compromise the cervical function of maintaining a **closed uterine orifice** during pregnancy. *5:1* - While higher than 2:1, this ratio still underestimates the true dominance of **connective tissue** in the cervical structure. - The **cervix's mechanical properties**, including its ability to resist stretching, are primarily due to its abundant collagen content. *15:1* - This ratio overestimates the proportion of connective tissue, suggesting less than 7% smooth muscle. - While the cervix is indeed fibrous, it does contain a modest amount of **smooth muscle** (10-15%) particularly in the internal os region, making this ratio too extreme [1].
Question 135: Helicine arteries are branches of which artery?
- A. None of the options
- B. Femoral artery
- C. External pudendal artery
- D. Internal pudendal artery (Correct Answer)
Explanation: ***Internal pudendal artery*** - The **internal pudendal artery** is the primary arterial supply to the external genitalia, and its branches, including the **helicine arteries**, are crucial for erectile function. - In males, these arteries supply the **corpus cavernosa** of the penis, and in females, they supply the **clitoris**, playing a key role in sexual arousal. *Femoral artery* - The **femoral artery** is a large artery in the thigh that supplies blood to the lower limb, but it does not directly branch into the helicine arteries of the genitalia. - Its main branches include the **deep femoral artery** and the **superficial femoral artery**, which are involved in blood supply to the muscles and skin of the thigh. *External pudendal artery* - The **external pudendal artery** branches off the femoral artery and supplies the skin of the external genitalia and the perineum, but not the deeper erectile tissues via helicine arteries. - It primarily provides superficial blood supply, such as to the **scrotum** or **labia majora**, and is distinct from the internal pudendal artery's deeper distribution. *None of the options* - This option is incorrect because the **internal pudendal artery** is indeed the origin of the helicine arteries. - The other options provided are incorrect as they do not directly give rise to the helicine arteries.
Question 136: Which of the following statements about the great saphenous vein is true?
- A. It begins at lateral end of dorsal venous arch
- B. It runs anterior to medial malleolus (Correct Answer)
- C. Terminates into popliteal vein
- D. It is accompanied by the sural nerve
Explanation: **It runs anterior to medial malleolus** - The **great saphenous vein** originates from the medial end of the **dorsal venous arch** of the foot and ascends anterior to the **medial malleolus** [1]. - This anatomical relationship makes it accessible for various clinical procedures, such as **venous cutdown** for rapid intravenous access [1]. *It begins at lateral end of dorsal venous arch* - The **great saphenous vein** actually begins at the **medial end** of the dorsal venous arch, not the lateral end [1]. - The **small saphenous vein** arises from the lateral end of the dorsal venous arch [1]. *It is accompanied by the sural nerve* - The **sural nerve** typically accompanies the **small saphenous vein**, not the great saphenous vein, in the posterior leg [1]. - The **saphenous nerve**, a branch of the femoral nerve, accompanies the great saphenous vein throughout its course in the leg. *Terminates into popliteal vein* - The **great saphenous vein** normally terminates by draining into the **femoral vein** in the femoral triangle, not the popliteal vein [1]. - The **small saphenous vein** is the one that typically drains into the popliteal vein [1].
Biochemistry
1 questionsWhat is the process of Hofmann elimination in organic chemistry?
NEET-PG 2013 - Biochemistry NEET-PG Practice Questions and MCQs
Question 131: What is the process of Hofmann elimination in organic chemistry?
- A. E1 elimination reaction favoring tertiary substrates
- B. E2 elimination reaction producing the least substituted alkene (Correct Answer)
- C. SN1 substitution reaction with carbocation intermediate
- D. SN2 substitution reaction with inversion of configuration
Explanation: ***E2 elimination reaction producing the least substituted alkene*** - **Hofmann elimination** is a type of **E2 elimination** reaction where a **quaternary ammonium salt** is heated in the presence of a strong base. - Unlike most E2 reactions which follow **Zaitsev's rule** (producing the most substituted alkene), Hofmann elimination follows the **Hofmann rule**, leading to the formation of the **least substituted (least stable) alkene**. *SN1 substitution reaction with carbocation intermediate* - **SN1 reactions** involve the formation of a **carbocation intermediate** and are typically substitution reactions, not elimination. - Hofmann elimination is an elimination reaction and does not proceed through a carbocation intermediate. *E1 elimination reaction favoring tertiary substrates* - **E1 reactions** are a two-step process involving a **carbocation intermediate** and generally favor **tertiary substrates** and produce the **Zaitsev product**. - Hofmann elimination is a concerted, one-step E2 mechanism and does not involve carbocations. *SN2 substitution reaction with inversion of configuration* - **SN2 reactions** are **bimolecular nucleophilic substitution** reactions that occur in a single step with **inversion of configuration** at the carbon center. - Hofmann elimination is an elimination process resulting in an alkene, not a substitution product, and does not involve inversion of configuration at a stereocenter.
Internal Medicine
2 questionsWhich of the following glands is NOT typically involved in Multiple Endocrine Neoplasia type II A (MEN II A)?
Which one of the following is the most common CNS tumor associated with type I neurofibromatosis?
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 131: Which of the following glands is NOT typically involved in Multiple Endocrine Neoplasia type II A (MEN II A)?
- A. Pituitary gland (Correct Answer)
- B. Thyroid gland
- C. Parathyroid gland
- D. Adrenal gland
Explanation: ***Pituitary gland*** - The **pituitary gland** is not a characteristic component of **MEN II A**. It is, however, associated with **Multiple Endocrine Neoplasia type I (MEN I)**, which involves the 3 Ps: **pituitary**, **parathyroid**, and **pancreas** [1]. - **MEN IIA** classically involves **medullary thyroid carcinoma**, **pheochromocytoma**, and **parathyroid hyperplasia** [1]. *Thyroid gland* - The **thyroid gland** is centrally involved in MEN IIA, specifically through the development of **medullary thyroid carcinoma (MTC)**, a hallmark feature. - MTC arises from the parafollicular C cells of the thyroid and secretes **calcitonin**. *Parathyroid gland* - The **parathyroid gland** is often involved in MEN IIA, typically presenting as **parathyroid hyperplasia** or adenoma, leading to **primary hyperparathyroidism**. - This typically results in elevated **parathyroid hormone** levels and **hypercalcemia**. *Adrenal gland* - The **adrenal gland** is a key player in MEN IIA due to the occurrence of **pheochromocytoma**, a tumor of the adrenal medulla. - Pheochromocytomas can be bilateral and secrete **catecholamines**, leading to hypertension and other symptoms.
Question 132: Which one of the following is the most common CNS tumor associated with type I neurofibromatosis?
- A. Optic nerve glioma (Correct Answer)
- B. Meningioma
- C. Acoustic schwannoma
- D. Low grade astrocytoma
Explanation: ***Optic nerve glioma*** - **Optic nerve gliomas** are the most frequently encountered central nervous system tumors in patients with **Type 1 neurofibromatosis (NF1)**, occurring in about 15% of individuals. - They are typically low-grade **astrocytomas** and can cause vision loss and proptosis depending on their size and location. *Meningioma* - While more common in **Type 2 neurofibromatosis (NF2)**, meningiomas can occur in NF1, but are not the most common CNS tumor. - Meningiomas are tumors that arise from the **meninges**, the membranes surrounding the brain and spinal cord. *Acoustic schwannoma* - **Bilateral acoustic schwannomas (vestibular schwannomas)** are the hallmark feature of **Type 2 neurofibromatosis (NF2)**, not NF1 [1]. - These tumors arise from the Schwann cells of the **vestibulocochlear nerve** and can cause hearing loss and balance issues [1]. *Low grade astrocytoma* - While optic nerve gliomas are a type of low-grade astrocytoma, this option is too general; **optic nerve glioma** is the specific and most common presentation in NF1. - Other forms of low-grade astrocytomas can occur in NF1 but are not as universally characteristic as optic nerve gliomas.
Pharmacology
1 questionsWhich route of administration undergoes the maximum first pass metabolism?
NEET-PG 2013 - Pharmacology NEET-PG Practice Questions and MCQs
Question 131: Which route of administration undergoes the maximum first pass metabolism?
- A. Intra-arterial
- B. Rectal
- C. Oral (Correct Answer)
- D. Intravenous
Explanation: ***Oral*** - Drugs administered orally are absorbed from the **gastrointestinal tract** and transported via the **portal vein** directly to the liver, where they undergo significant **first-pass metabolism** before reaching systemic circulation. - This hepatic metabolism can drastically reduce the **bioavailability** of the drug, requiring higher doses or alternative administration routes. *Intra-arterial* - This route delivers drugs directly into an **artery** supplying a target tissue or organ, largely bypassing systemic circulation and initial hepatic metabolism. - It is used for localized effects, such as **chemotherapy** for specific tumors, minimizing systemic exposure. *Rectal* - While a portion of rectally administered drugs may bypass the portal circulation by entering the **inferior and middle rectal veins**, a significant amount can still be absorbed into the superior rectal vein, which drains into the portal system. - This means rectal administration offers only **partial avoidance** of first-pass metabolism, making it less complete than IV or intra-arterial routes for bypassing the liver altogether. *Intravenous* - Drugs administered intravenously are delivered directly into the **systemic circulation**, completely bypassing the gastrointestinal tract and the liver's first-pass metabolism. - This route ensures **100% bioavailability** and rapid onset of action, as the drug immediately reaches its target.