Anatomy
6 questionsWhich is the primary segment of the liver drained by the right hepatic vein?
Where is the Bartholin gland situated?
What is the lower limit of the retropharyngeal space?
Maxillary bone does not articulate with:
What is the typical length of a human sperm cell?
Which muscle stabilizes the clavicle during movement of the shoulder?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 111: Which is the primary segment of the liver drained by the right hepatic vein?
- A. I
- B. II
- C. IV
- D. VII (Correct Answer)
Explanation: ***VII*** - The **right hepatic vein** drains the **posterior segment** of the right lobe, which includes segments **VI and VII**. Segment VII is particularly well-drained by this vein. [3] - Understanding hepatic venous drainage is crucial for **surgical planning** and interpreting imaging studies of the liver. [4] *I* - Segment I, the **caudate lobe**, is unique in its venous drainage, often by small veins directly into the **inferior vena cava (IVC)** or occasionally into the left and middle hepatic veins. [1] - It has a separate blood supply and drainage which differentiates it from other segments. [4] *II* - Segment II is part of the **left lateral segment** and is primarily drained by the **left hepatic vein**. - The left hepatic vein typically drains segments II and III. [2] *IV* - Segment IV, or the **quadrate lobe**, is primarily drained by the **middle hepatic vein**. - The middle hepatic vein also drains segment VIII and the anterior aspect of segment V.
Question 112: Where is the Bartholin gland situated?
- A. Superficial perineal pouch (Correct Answer)
- B. Deep perineal pouch
- C. Inguinal canal
- D. Ischiorectal fossa
Explanation: ***Superficial perineal pouch*** - The **Bartholin glands** are located posterolateral to the vaginal orifice within the boundaries of the **superficial perineal pouch** [1]. - They are covered by the **bulbospongiosus muscle** and their ducts open into the vestibule of the vagina [1]. *Deep perineal pouch* - This pouch contains structures like the **urethra**, part of the **vagina**, and the **deep transverse perineal muscle**, but not the Bartholin glands [2]. - It is located superior to the superficial perineal pouch and separated by the **perineal membrane**. *Inguinal canal* - The **inguinal canal** is a passage in the anterior abdominal wall that transmits the **round ligament of the uterus** in females and the **spermatic cord** in males. - It is anatomically distinct from the perineum and does not house the Bartholin glands. *Ischiorectal fossa* - The **ischiorectal fossae** are fat-filled spaces located lateral to the anal canal, inferior to the levator ani muscles. - They are known for their susceptibility to abscess formation but do not contain the Bartholin glands.
Question 113: What is the lower limit of the retropharyngeal space?
- A. Bifurcation of trachea (Correct Answer)
- B. 4th esophageal constriction
- C. C7
- D. None of the options
Explanation: Bifurcation of trachea - The retropharyngeal space extends inferiorly to approximately the level of T4-T5 vertebrae, corresponding to the bifurcation of the trachea and the superior mediastinum. - This space lies between the buccopharyngeal fascia (posterior to pharynx) and the alar layer of prevertebral fascia. - Clinically, infections or abscesses in this space can descend into the posterior mediastinum, making knowledge of this inferior extent crucial for surgical management. - Note: Some anatomical texts describe the space ending at T1-T2, but for clinical and surgical purposes, the functional inferior limit extends to the bifurcation of the trachea. C7 - While some texts describe the retropharyngeal space as terminating around C7 (level of the lower border of cricoid cartilage), this represents the narrower definition. - The clinical and surgical definition extends the space further inferiorly to allow for tracking of infections into the chest. - C7 alone does not represent the accepted lower limit for examination purposes. 4th esophageal constriction - The fourth esophageal constriction is not a standard anatomical landmark (esophagus has 3-4 constrictions depending on classification). - Esophageal constrictions are luminal narrowings within the esophagus itself and do not define the boundaries of the retropharyngeal space, which is a fascial space posterior to both pharynx and esophagus. None of the options - This is incorrect because bifurcation of the trachea is the recognized lower limit of the retropharyngeal space for clinical and examination purposes. - Understanding this anatomical boundary is essential for predicting the spread of deep neck space infections.
Question 114: Maxillary bone does not articulate with:
- A. Frontal
- B. Lacrimal
- C. Sphenoid
- D. Ethmoid (Correct Answer)
Explanation: ***Ethmoid (Marked Correct - PYQ 2012)*** - This question reflects traditional teaching where the **maxilla-ethmoid articulation** was considered minimal or indirect. - In modern anatomy, the **maxilla DOES articulate with the ethmoid bone** via the uncinate process of the ethmoid and the medial wall of the maxillary sinus. - However, per the **NEET-PG 2012 answer key**, ethmoid was accepted as the correct answer, likely because this articulation is small and often not emphasized in basic anatomy teaching. - The maxilla has major articulations with: frontal, zygomatic, nasal, lacrimal, palatine, inferior nasal concha, vomer, and contralateral maxilla. *Sphenoid* - The **maxilla clearly articulates** with the **greater wing of the sphenoid bone** at the inferior orbital fissure. - This articulation is substantial and forms the posterolateral floor of the orbit. - The sphenoid-maxillary articulation contributes to the boundaries of the **pterygopalatine fossa**. *Frontal* - The **maxilla articulates extensively** with the **frontal bone** at the frontomaxillary suture. - This articulation forms the medial orbital rim and part of the anterior cranial floor interface. - This is one of the most prominent maxillary articulations. *Lacrimal* - The **maxilla articulates directly** with the **lacrimal bone**, forming the anterior part of the medial orbital wall. - Together they form the **lacrimal groove** which houses the lacrimal sac. - This articulation is essential for the nasolacrimal drainage pathway.
Question 115: What is the typical length of a human sperm cell?
- A. 55 micrometers (Correct Answer)
- B. 50 micrometers
- C. 100 micrometers
- D. 65 micrometers
Explanation: ***55 micrometers*** - A typical **human sperm cell** measures approximately **55 micrometers** from the head to the tip of the tail [1]. - This length allows for efficient motility and navigation within the female reproductive tract to reach the ovum [1]. *100 micrometers* - This length is significantly **longer** than the average size of a human sperm cell. - While some cells can achieve this size, it is not typical for **spermatozoa**. *65 micrometers* - Although closer to the actual size, **65 micrometers** is generally considered slightly larger than the average human sperm cell length. - Sperm length is critical for understanding their **mobility** and **fertility** [1]. *50 micrometers* - This measurement is slightly **shorter** than the typical length of a human sperm cell. - The precise length, including the **head** and **flagellum**, contributes to its function.
Question 116: Which muscle stabilizes the clavicle during movement of the shoulder?
- A. Pectoralis major
- B. Latissimus dorsi
- C. Subclavius (Correct Answer)
- D. Serratus anterior
Explanation: ***Subclavius*** - The **subclavius muscle** originates from the first rib and inserts into the inferior surface of the clavicle, acting to **depress the clavicle** and prevent its displacement, thus enhancing shoulder stability during movement. - It plays a crucial role in protecting the underlying **neurovascular structures** (brachial plexus and subclavian vessels) from external trauma to the shoulder. *Pectoralis major* - This large, fan-shaped muscle primarily functions in **adduction, medial rotation, and flexion of the humerus** at the shoulder joint [1]. - It does not directly stabilize the clavicle but rather acts on the arm. *Latissimus dorsi* - The **latissimus dorsi** is a broad muscle of the back responsible for **extension, adduction, and internal rotation of the humerus** [1]. - Its actions are mainly on the humerus and it does not directly stabilize the clavicle. *Serratus anterior* - The **serratus anterior** muscle primarily **protracts and rotates the scapula**, keeping it pressed against the thoracic wall. - While it's essential for **scapular stability** and overhead arm movements, it does not directly stabilize the clavicle.
Internal Medicine
2 questionsIn which condition is venous blood most commonly observed to have a high hematocrit in routine clinical practice?
All of the following statements about the third heart sound (S3) are true, except:
NEET-PG 2012 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 111: In which condition is venous blood most commonly observed to have a high hematocrit in routine clinical practice?
- A. Dehydration (Correct Answer)
- B. Anemia
- C. Hypervolemia
- D. Acute blood loss
Explanation: Dehydration - In **dehydration**, the total body water is reduced, leading to a decrease in plasma volume [1, 5]. This concentrates the red blood cells, resulting in a relatively **high hematocrit**. [3] - This is a common finding as the body attempts to conserve fluid, making it a primary cause of **elevated hematocrit** in clinical practice. *Anemia* - **Anemia** is characterized by a decrease in the number of red blood cells or a reduced hemoglobin concentration, which would lead to a **low hematocrit**, not a high one [2]. - This condition involves insufficient oxygen-carrying capacity due to a deficiency in red blood cells or hemoglobin [2]. *Hypervolemia* - **Hypervolemia** describes an excess of fluid in the blood, which would dilute the blood components, leading to a relatively **low hematocrit** [1]. - This condition is often associated with conditions like heart failure or kidney disease, where fluid retention is common. *Acute blood loss* - In **acute blood loss**, the loss of whole blood immediately after the event would initially reduce both red blood cells and plasma proportionally, not immediately raising hematocrit [2]. - As the body attempts to compensate by shifting extravascular fluid into the circulation, this would further dilute the blood, eventually leading to a **decreased hematocrit** [2].
Question 112: All of the following statements about the third heart sound (S3) are true, except:
- A. Seen in Atrial Septal Defect (ASD)
- B. Seen in Ventricular Septal Defect (VSD)
- C. Occurs due to rapid filling of the ventricles during early diastole.
- D. Seen in Constrictive Pericarditis (Correct Answer)
Explanation: ***Seen in Constrictive Pericarditis*** - While constrictive pericarditis can lead to a diastolic sound, it's typically a **pericardial knock**, which is sharper and occurs earlier than an S3, due to abrupt halting of ventricular filling. - A true S3 is a low-pitched sound caused by turbulent blood flow into an overly compliant or volume-overloaded ventricle, which is not the primary mechanism in constrictive pericarditis. *Occurs due to rapid filling of the ventricles during early diastole.* - The S3 heart sound is precisely caused by the **rapid inflow of blood** into a dilated or poorly compliant ventricle during the early, rapid filling phase of diastole [1]. - This rapid distension causes vibrations in the ventricular wall, audible as S3, and is often associated with conditions causing **volume overload** or **ventricular dysfunction**. *Seen in Atrial Septal Defect (ASD)* - Patients with a large ASD have increased blood flow through the tricuspid valve, leading to **right ventricular volume overload** [2]. - This increased volume can cause an **S3** sound, particularly a **right ventricular S3**, due to rapid filling of the overloaded right ventricle [2]. *Seen in Ventricular Septal Defect (VSD)* - A significant VSD leads to a **left-to-right shunt**, increasing blood flow to the pulmonary circulation and subsequently returning to the left atrium and left ventricle. - This **left ventricular volume overload** can result in an audible **left ventricular S3**, reflecting rapid filling of the dilated left ventricle.
Physiology
2 questionsANP acts at which site?
Which of the following is most important in sodium and water retention ?
NEET-PG 2012 - Physiology NEET-PG Practice Questions and MCQs
Question 111: ANP acts at which site?
- A. Glomerulus
- B. Loop of Henle
- C. PCT
- D. Collecting duct (Correct Answer)
Explanation: ***Collecting duct*** - Atrial Natriuretic Peptide (**ANP**) exerts its primary effect on the **collecting duct** by inhibiting sodium reabsorption, leading to increased sodium and water excretion (natriuresis and diuresis). - This action helps to reduce blood volume and blood pressure in conditions like **hypervolemia**. *Glomerulus* - While ANP does cause **afferent arteriolar dilation** and **efferent arteriolar constriction**, increasing **glomerular filtration rate** (GFR), its direct tubular action is most prominent in the collecting duct. - The primary function of the glomerulus is **filtration**, influenced by many factors including pressure, but it is not the main site of ANP's direct tubular reabsorptive effects. *Loop of Henle* - The loop of Henle is responsible for establishing the **medullary osmotic gradient** and reabsorbing a significant amount of sodium and water. - ANP has minor effects on the loop of Henle, but its most impactful reabsorptive modulation occurs downstream in the collecting duct. *PCT* - The **proximal convoluted tubule (PCT)** is where the bulk of reabsorption of filtered substances (e.g., glucose, amino acids, most sodium and water) occurs. - ANP has very little direct influence on the reabsorptive processes of the PCT.
Question 112: Which of the following is most important in sodium and water retention ?
- A. Renin angiotensin system (Correct Answer)
- B. ANP
- C. BNP
- D. Vasopressin
Explanation: ***Renin angiotensin system*** - The **renin-angiotensin-aldosterone system (RAAS)** is the most important mechanism for **both sodium AND water retention**, which is what the question specifically asks about. - **Aldosterone** directly promotes **sodium reabsorption** in the principal cells of the collecting duct by increasing apical ENaC channels and basolateral Na-K-ATPase pumps. - **Angiotensin II** stimulates sodium reabsorption in the proximal tubule and also stimulates ADH release, contributing to water retention. - When sodium is retained, **water follows passively** due to the osmotic gradient, resulting in effective volume expansion. - RAAS is the primary system activated in states of volume depletion and is most important for combined sodium and water retention. *Vasopressin* - **Vasopressin (ADH)** primarily controls **water retention only** by increasing aquaporin-2 channels in the collecting duct. - While crucial for water balance, it has minimal direct effect on sodium reabsorption. - It causes retention of **free water**, which can actually dilute plasma sodium concentration. - ADH is the answer if the question asked about water retention alone, but not for combined sodium and water retention. *ANP* - **Atrial natriuretic peptide (ANP)** promotes **sodium and water excretion** (natriuresis and diuresis). - Released in response to atrial stretch from volume expansion. - Acts to *oppose* retention mechanisms, making it incorrect for this question. *BNP* - **Brain natriuretic peptide (BNP)** similarly promotes **natriuresis and diuresis**. - Released from ventricular myocytes in response to volume overload. - Like ANP, it acts to *excrete* sodium and water, not retain them.