NEET-PG 2013 Practice Questions

Q: All are supplied by the anterior interosseous nerve except which of the following?

Flexor carpi ulnaris. ***Flexor carpi ulnaris*** - The **flexor carpi ulnaris** (FCU) is innervated by the **ulnar nerve**, not the anterior interosseous nerve [1]. - This is the correct answer as it is NOT supplied by the AIN. *Pronator quadratus* - The **pronator quadratus** IS supplied by the **anterior interosseous nerve**. - This deep muscle is responsible for **pronation of the forearm** and is one of the three muscles innervated by the AIN. *Flexor digitorum profundus (lateral half)* - The **lateral half of flexor digitorum profundus** (to index and middle fingers) IS supplied by the **anterior interosseous nerve**. - The medial half (to ring and little fingers) is supplied by the ulnar nerve. *Flexor pollicis longus* - The **flexor pollicis longus** (FPL) IS supplied by the **anterior interosseous nerve**. - This muscle is responsible for **flexion of the thumb's interphalangeal joint** and is one of the three muscles innervated by the AIN.

Q: Which of the following is not a tributary of the cavernous sinus?

Inferior cerebral vein. Detailed anatomical knowledge of the dural venous sinuses is required to answer this question. Venous drainage from the brain by way of the deep veins and dural sinuses typically empties principally into the internal jugular veins, though blood also drains via the ophthalmic and pterygoid venous plexuses [1]. ***Inferior cerebral vein*** - The **inferior cerebral veins** drain the inferior surface of the cerebral hemispheres and typically empty into the **basal vein of Rosenthal**, **transverse sinus**, or other dural sinuses. - They do **not directly drain** into the cavernous sinus, making this the correct answer. - While some small inferior cerebral veins may occasionally communicate with the cavernous sinus, they are not considered standard tributaries. *Central vein of retina* - The **central vein of retina** drains the retina and exits the eye through the optic nerve. - It drains into the **superior ophthalmic vein**, which then empties into the cavernous sinus. - It is an **indirect tributary** via the superior ophthalmic vein, not a direct tributary itself. *Sphenoparietal sinus* - The **sphenoparietal sinus** is a dural venous sinus that runs along the posterior edge of the lesser wing of the sphenoid bone. - It is a **direct tributary** that drains anteriorly into the cavernous sinus. - This is one of the standard tributaries listed in anatomical texts. *Superior ophthalmic vein* - The **superior ophthalmic vein** is the **major tributary** draining orbital structures including the eyeball, extraocular muscles, and eyelids. - It passes posteriorly through the **superior orbital fissure** to drain directly into the cavernous sinus. - This is the most clinically significant tributary, as infections can spread from the face to the cavernous sinus via this route.

Q: What is the most dependent part of the peritoneal cavity in a female in the standing position?

Pouch of Douglas. ***Pouch of Douglas*** - The **rectouterine pouch** (Pouch of Douglas) is the most dependent part of the peritoneal cavity in females when standing. - It lies between the **rectum posteriorly** and the **uterus anteriorly**, extending down to the posterior fornix of the vagina [1]. - Due to gravity, any free fluid in the peritoneal cavity (blood, pus, ascitic fluid) collects here in the upright position. - **Clinical significance:** This is why culdocentesis (needle aspiration through the posterior vaginal fornix) can detect intraperitoneal fluid [1]. *Vesicouterine pouch* - Located between the **uterus posteriorly** and the **bladder anteriorly** [1]. - It is **superior** to the Pouch of Douglas and therefore not the most dependent part. - Fluid would collect in the Pouch of Douglas before reaching this pouch in a standing position. *Paracolic gutter* - The **paracolic gutters** are peritoneal recesses lateral to the ascending and descending colon. - While they can collect fluid, they are **not the lowest point** in the peritoneal cavity in an upright position. - The right paracolic gutter can serve as a pathway for fluid to spread between the pelvis and subphrenic spaces. *None of the options* - This is incorrect as the **Pouch of Douglas** is definitively the most dependent part of the peritoneal cavity in females in the standing position. - It is a well-established anatomical fact taught in all standard anatomy textbooks.

Q: Esophagus is present in which mediastinum?

Posterior. ***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.

Q: Which of the following statements regarding collagen synthesis is incorrect?

Hydroxylation of proline occurs in Golgi apparatus. ***Hydroxylation of proline occurs in Golgi apparatus*** - This statement is incorrect because the **hydroxylation of proline** residues occurs in the **endoplasmic reticulum** (ER), not the Golgi apparatus. - This step is critical for forming stable **triple helix** structures of collagen and requires **vitamin C**. *Synthesized in ribosomes as preprocollagen* - This statement is correct. Collagen synthesis begins in the cytoplasm, where mRNA is translated by **ribosomes** into **preprocollagen**, which contains a signal peptide. - The signal peptide directs the nascent polypeptide chain into the lumen of the **endoplasmic reticulum**. *Hydroxylation of lysine occurs in ER* - This statement is correct. Following entry into the ER, specific **lysine** residues are hydroxylated by **lysyl hydroxylase** to form hydroxylysine. - This hydroxylation, along with that of proline, is crucial for **cross-linking** and stability of the collagen molecule. *Triple helix assembly occurs in ER* - This statement is correct. After hydroxylation and glycosylation of some residues, three procollagen alpha chains self-assemble to form a **triple helix** within the **endoplasmic reticulum**. - This assembly is stabilized by **disulfide bonds** at the C-terminal ends and molecular chaperones.

Q: Intracorpuscular hemolytic anemia is seen in ?

Thalassemia. ***Thalassemia*** - Thalassemia is characterized by **intracorpuscular hemolysis** due to defective hemoglobin synthesis, leading to premature destruction of red blood cells [1][2]. - It manifests as **microcytic anemia** with associated **extramedullary erythropoiesis** in severe cases [1]. *Autoimmune hemolytic anemia* - This condition leads to **extravascular hemolysis**, primarily affecting red blood cells in the spleen, not within the plasma [2]. - It is often associated with **positive direct Coombs test**, indicating reactants on the RBC surface. *TIP* - TIP (Thrombotic Microangiopathy) primarily involves **microangiopathic hemolytic anemia** and is not classified as intracorpuscular [2]. - The hemolysis in TIP occurs due to **microthrombi**, causing damage to red blood cells as they pass through narrowed vessels. *Infection* - Infections can lead to **hemolysis**, but this is typically **extravascular** due to splenic clearance or due to other mechanisms like **malaria** [2]. - The hemolytic mechanism is not intracorpuscular, as seen in conditions like thalassemia. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 601-602. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 596-597.

Q: In the context of pharmacology, which plasma protein do acidic drugs primarily bind to?

Albumin. ***Albumin*** - **Albumin** is the most abundant plasma protein and has multiple binding sites for a wide range of drugs, particularly **acidic drugs**. - Its high concentration and diverse binding capabilities make it the primary transporter for many **lipophilic** and **anionic drugs**. *Globulin* - **Globulins** are a diverse group of proteins, some of which bind to drugs, but they primarily transport **hormones**, **metals**, and **vitamins**, not acidic drugs. - They are less significant for binding acidic drugs compared to albumin. *α1-acid glycoprotein* - **α1-acid glycoprotein** primarily binds to **basic drugs** due to its numerous acidic residues. - While it plays a crucial role in binding basic compounds, it has limited affinity for acidic drugs. *None of the options* - This option is incorrect because **albumin** is a well-established and significant plasma protein for binding acidic drugs. - Specific plasma proteins are known to bind different types of drugs, and for acidic drugs, albumin is the primary binder.

Q: How many transmembrane spanning domains does the Na+-K+-Cl- cotransporter contain?

12 transmembrane spanning domain. ***12 transmembrane spanning domain*** - The **Na+-K+-Cl- cotransporter (NKCC)**, specifically NKCC1 and NKCC2 isoforms, is a multipass transmembrane protein. - It is known to contain **12 transmembrane spanning domains**, which are α-helical regions that cross the cell membrane. *5 transmembrane spanning domain* - This number is **too low** for the complex structure of the NKCC cotransporter. - Proteins with 5 transmembrane domains typically have different functional roles and structural characteristics. *7 transmembrane spanning domain* - This number is characteristic of **G protein-coupled receptors (GPCRs)**, a distinct family of membrane proteins. - The NKCC cotransporter functions as an ion transporter and does not share the structural motif of GPCRs. *9 transmembrane spanning domain* - This number is also **insufficient** to describe the known topology of the NKCC cotransporter. - Ion transporters like NKCC generally require a higher number of transmembrane domains to form the necessary pore and binding sites.

Q: Which hormone acts on JAK-STAT kinase receptor?

GH. ***GH*** - **Growth Hormone (GH)** binds to a **cytokine receptor** that lacks intrinsic tyrosine kinase activity and instead signals through associated **JAK-STAT kinases**. - This binding leads to **JAK phosphorylation**, which then phosphorylates and activates **STAT proteins**, regulating gene expression. *TSH* - **Thyroid-stimulating hormone (TSH)** acts on a **G protein-coupled receptor** to stimulate thyroid hormone production and release. - Its signaling pathway primarily involves the activation of **adenylyl cyclase** and increases in **cAMP**, not the JAK-STAT pathway. *Thyroxine* - **Thyroxine (T4)** is a **thyroid hormone** that primarily acts by binding to **intracellular nuclear receptors**, which then regulate gene transcription. - It directly influences gene expression, rather than signaling through cell surface receptors and kinase pathways like JAK-STAT. *FSH* - **Follicle-stimulating hormone (FSH)**, like TSH, signals through a **G protein-coupled receptor** on target cells in the gonads. - This activation primarily leads to an increase in **intracellular cAMP levels** to mediate its effects on gamete production and hormone synthesis.

Q: By what percentage can cardiac output increase in a healthy adult during intense physical activity compared to resting levels?

300 - 400 %. ***300 - 400 %*** - In a healthy adult, **cardiac output** can increase remarkably during intense physical activity. - The heart can increase its output by **3 to 4 times** (or 300-400%) above resting levels during peak exertion. - At rest, cardiac output is approximately **5 L/min**, but during maximal exercise, it can reach **20-25 L/min** in well-conditioned individuals. - This represents the heart's **reserve capacity** to meet increased metabolic demands during exercise. *0 - 50 %* - This range represents a very **limited increase** in cardiac output and would be indicative of significant underlying cardiac impairment or **heart failure**. - A healthy individual would experience a much greater increase in cardiac output during intense activity than this small percentage. *50 - 100 %* - This range also suggests a **suboptimal cardiac response** for a healthy adult undergoing intense physical activity. - While some increase is present, it does not reflect the full capacity of a healthy cardiovascular system to adapt to extreme demands. *100 - 200 %* - While a 100-200% increase is substantial, it still **underestimates the maximal capacity** achievable in a healthy, well-conditioned individual during intense physical exertion. - The heart has a greater capacity for increasing its output to meet metabolic demands during peak exercise.

Question 1

All are supplied by the anterior interosseous nerve except which of the following?

Accepted Answer

Flexor carpi ulnaris

Answer

Pronator quadratus

Answer

Flexor digitorum profundus (lateral half)

Answer

Flexor pollicis longus

Question 2

Which of the following is not a tributary of the cavernous sinus?

Accepted Answer

Inferior cerebral vein

Answer

Central vein of retina

Answer

Sphenoparietal sinus

Answer

Superior ophthalmic vein

Question 3

What is the most dependent part of the peritoneal cavity in a female in the standing position?

Accepted Answer

Pouch of Douglas

Answer

Vesicouterine pouch

Answer

Paracolic gutter

Answer

None of the options

Question 4

Esophagus is present in which mediastinum?

Accepted Answer

Posterior

Answer

Answer

Middle

Answer

Superior

Question 5

Which of the following statements regarding collagen synthesis is incorrect?

Accepted Answer

Hydroxylation of proline occurs in Golgi apparatus

Answer

Hydroxylation of lysine occurs in ER

Answer

Synthesized in ribosomes as preprocollagen

Answer

Triple helix assembly occurs in ER

Question 6

Intracorpuscular hemolytic anemia is seen in ?

Accepted Answer

Thalassemia

Answer

Infection

Answer

Thrombotic thrombocytopenic purpura (TTP)

Answer

Autoimmune hemolytic anemia

Question 7

In the context of pharmacology, which plasma protein do acidic drugs primarily bind to?

Accepted Answer

Albumin

Answer

Globulin

Answer

α1-acid glycoprotein

Answer

None of the options

Question 8

How many transmembrane spanning domains does the Na+-K+-Cl- cotransporter contain?

Accepted Answer

12 transmembrane spanning domain

Answer

5 transmembrane spanning domain

Answer

7 transmembrane spanning domain

Answer

9 transmembrane spanning domain

Question 9

Which hormone acts on JAK-STAT kinase receptor?

Accepted Answer

GH

Answer

TSH

Answer

Thyroxine

Answer

FSH

Question 10

By what percentage can cardiac output increase in a healthy adult during intense physical activity compared to resting levels?

Accepted Answer

300 - 400 %

Answer

0 - 50 %

Answer

50 - 100 %

Answer

100 - 200 %

NEET-PG 2013

Anatomy

Biochemistry

Pathology

Pharmacology

Physiology