Anatomy
5 questionsWhich of the following is not a boundary of Koch's triangle?
Where is the Bartholin gland situated?
Lymphatic drainage of cervix is to
Which is derived from Wolffian duct?
In walking, gravity tends to tilt pelvis and trunk to the unsupported side, the major factor in preventing this unwanted movement is?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 171: Which of the following is not a boundary of Koch's triangle?
- A. Limbus fossa ovalis (Correct Answer)
- B. Tricuspid valve ring
- C. Coronary sinus
- D. Tendon of Todaro
Explanation: ***Limbus fossa ovalis*** - The **limbus fossa ovalis** is a prominent oval ridge on the **interatrial septum** that surrounds the fossa ovalis. - It is **not involved** in forming the boundaries of Koch's triangle, which is located in the **right atrium** near the AV node [1]. *Tricuspid valve ring* - The **tricuspid valve ring** (or annulus) forms one of the key anatomical boundaries of **Koch's triangle**, specifically its base [1]. - This **fibrous ring** anchors the tricuspid valve leaflets and marks the inferior aspect of the triangle [1]. *Coronary sinus* - The **coronary sinus ostium** (opening) forms another crucial boundary of **Koch's triangle** [1]. - It is located at the **inferior-posterior aspect** of the interatrial septum, opening into the right atrium [1]. *Tendon of todaro* - The **Tendon of Todaro** is a fibrous structure that forms the superior boundary of **Koch's triangle** [1]. - It extends from the **Eustachian valve** (of the inferior vena cava) towards the central fibrous body, playing a role in **AV nodal localization** [1].
Question 172: 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 173: Lymphatic drainage of cervix is to
- A. Iliac lymph nodes (Correct Answer)
- B. Para-aortic lymph nodes
- C. Deep inguinal lymph nodes
- D. Superficial inguinal lymph nodes
Explanation: ***Iliac lymph nodes*** - The primary lymphatic drainage of the cervix is to the **internal**, **external**, and **common iliac lymph nodes**. - This pathway is crucial for understanding the spread of **cervical cancer**. *Para-aortic lymph nodes* - While sometimes involved in advanced cases, the **para-aortic nodes** are typically considered a secondary drainage site, usually after the iliac nodes are affected. - They are the primary drainage for organs like the **ovaries** and **testes**. *Deep inguinal lymph nodes* - These nodes primarily drain structures of the **lower limb** and some external genital areas, but not the cervix directly. - They are located deeper in the groin region, distinct from the internal pelvic drainage. *Superficial inguinal lymph nodes* - These nodes drain the **skin of the lower abdomen**, perineum, and external genitalia, as well as the lower limbs. - They do not receive direct lymphatic drainage from the **cervix**.
Question 174: Which is derived from Wolffian duct?
- A. Appendix of epididymis (Correct Answer)
- B. Appendix of the testis
- C. Uterine structure
- D. Hydatid of Morgagni
Explanation: The **appendix of the epididymis** is a vestigial structure directly derived from the mesonephric (Wolffian) duct in males. It is an embryological remnant of this duct, located at the head of the epididymis. *Appendix of the testis* - The **appendix of the testis** (hydatid of Morgagni) is a remnant of the paramesonephric (Müllerian) duct, not the Wolffian duct. - It is usually found on the upper pole of the testis, typically near the epididymis. *Uterine structure* - **Uterine structures** (uterus, fallopian tubes, and upper vagina) are derived from the paramesonephric (Müllerian) ducts in females [1]. - The Wolffian ducts largely regress in females due to the absence of testosterone. *Hydatid of Morgagni* - The term **hydatid of Morgagni** can refer to the appendix of the testis (Müllerian duct remnant) or, less commonly, to the appendix of the epididymis (Wolffian duct remnant). - However, in common clinical and anatomical usage, it almost exclusively refers to the **appendix of the testis**, which is a Müllerian duct derivative.
Question 175: In walking, gravity tends to tilt pelvis and trunk to the unsupported side, the major factor in preventing this unwanted movement is?
- A. Adductor muscles
- B. Quadriceps
- C. Gluteus medius and minimus (Correct Answer)
- D. Gluteus maximus
Explanation: ***Gluteus medius and minimus*** - The **gluteus medius** and **gluteus minimus** are essential **abductors** of the hip, primarily responsible for stabilizing the pelvis during the **single-limb support phase of gait**. - When one leg is lifted during walking, these muscles on the **stance leg side** contract to prevent the pelvis from tilting downwards on the unsupported swing leg side. *Adductor muscles* - **Adductor muscles** (adductor longus, brevis, magnus, pectineus, gracilis) primarily function to bring the thigh toward the midline of the body. - While they play a role in gait stability, their main action is not to prevent the lateral pelvic tilt described. *Quadriceps* - The quadriceps femoris group (rectus femoris, vastus lateralis, medialis, intermedius) are powerful **extensors of the knee**. - They are crucial for weight acceptance and propulsion during walking but do not directly prevent lateral pelvic tilt [1]. *Gluteus maximus* - The **gluteus maximus** is the largest and most powerful muscle of the hip, primarily responsible for **hip extension** and **external rotation**. - It is crucial for activities like climbing stairs or running, but its main role in normal walking is not to prevent lateral pelvic tilt; that function is more specific to the gluteus medius and minimus.
Internal Medicine
2 questionsWhich of the following is the most characteristic symptom of obstruction of the inferior vena cava?
In which condition is venous blood most commonly observed to have a high hematocrit in routine clinical practice?
NEET-PG 2012 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 171: Which of the following is the most characteristic symptom of obstruction of the inferior vena cava?
- A. Paraumblical dilatation (Correct Answer)
- B. Thoraco-epigastric dilatation
- C. Haemorrhoides
- D. Oesophageal varices
Explanation: ***Paraumbilical dilatation*** - Obstruction of the **inferior vena cava (IVC)** leads to collateral circulation through superficial veins, especially around the umbilicus, causing **paraumbilical dilatation** (caput medusae). - This collateral flow bypasses the obstructed IVC to return blood to the superior vena cava system. *Thoraco-epigastric dilatation* - This pattern of collateral circulation is more characteristic of **superior vena cava (SVC) obstruction**, where blood from the upper body needs to bypass the SVC. - The dilated veins would typically be seen on the chest and upper abdomen, draining towards the femoral veins. *Oesophageal varices* - **Oesophageal varices** are typically caused by **portal hypertension** [1], often secondary to liver cirrhosis, not directly by IVC obstruction. - They represent portosystemic collateral veins, diverging from the portal system to the systemic circulation [1]. *Haemorrhoids* - **Haemorrhoids** are dilated veins in the anal canal, most commonly caused by **straining** during defecation or conditions that increase intra-abdominal pressure [2]. - While they can be a sign of portal hypertension [1], **IVC obstruction** is not their primary or most characteristic cause.
Question 172: 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].
Physiology
3 questionsWhat is the normal range of interstitial pressure?
ANP acts at which site?
What is the effect of acetylcholine on the Lower Esophageal Sphincter (LES)?
NEET-PG 2012 - Physiology NEET-PG Practice Questions and MCQs
Question 171: What is the normal range of interstitial pressure?
- A. -3 to 0 mmHg
- B. -5 to 0 mmHg (Correct Answer)
- C. 0 to 5 mmHg
- D. 5 to 10 mmHg
Explanation: ***-5 to 0 mmHg*** - The interstitial fluid is normally under a **slight negative pressure**, typically ranging from **-5 to 0 mmHg** - This negative pressure helps pull fluid from the capillaries into the interstitial space and facilitates **lymphatic drainage** - Maintained by continuous drainage of fluid and proteins by the **lymphatic system** - This range is the commonly accepted value in standard physiology references for Indian medical exams *-3 to 0 mmHg* - While this range acknowledges the typically **negative nature** of interstitial pressure, it represents a slightly narrower range - Some sources cite this as the average range, but **-5 to 0 mmHg** is the more commonly accepted standard range - Not the most precise or widely cited range for exam purposes *0 to 5 mmHg* - This range suggests a **positive interstitial pressure**, which is generally **abnormal** - Indicates **edema formation** due to excess fluid accumulation in the interstitial space - Positive pressure impairs fluid reabsorption and lymphatic drainage - Represents pathological fluid dynamics *5 to 10 mmHg* - Represents significant **positive interstitial pressure** leading to severe **interstitial edema** - Markedly impairs tissue function and fluid exchange - Indicates pathological conditions where capillary filtration far exceeds lymphatic drainage capacity - Associated with severe edematous states
Question 172: 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 173: What is the effect of acetylcholine on the Lower Esophageal Sphincter (LES)?
- A. Causes contraction (Correct Answer)
- B. Causes relaxation
- C. No effect on LES
- D. Contraction followed by relaxation
Explanation: ***Correct Option: Causes contraction*** - Acetylcholine acts on **M3 muscarinic receptors** on LES smooth muscle cells to cause **contraction** - This is part of the **excitatory cholinergic pathway** that maintains LES tone and prevents gastroesophageal reflux - Acetylcholine is released from **excitatory motor neurons** in the myenteric plexus *Incorrect: Causes relaxation* - LES relaxation during swallowing is mediated by **nitric oxide (NO)** and **vasoactive intestinal peptide (VIP)**, NOT acetylcholine - These inhibitory neurotransmitters are released from separate **inhibitory motor neurons** - The relaxation response during swallowing is due to activation of the inhibitory pathway, which suppresses cholinergic tone *Incorrect: No effect on LES* - Acetylcholine has a significant effect on the LES - It is one of the key neurotransmitters maintaining basal LES tone - Loss of cholinergic input can lead to decreased LES pressure *Incorrect: Contraction followed by relaxation* - Acetylcholine itself causes only contraction - The swallowing reflex involves coordinated activation of inhibitory (NO/VIP) and suppression of excitatory (acetylcholine) pathways - The sequence of events is neural, not a biphasic response to acetylcholine alone