NEET-PG 2012 Practice Questions

Q: Lymphatic drainage of cervix is to

Iliac lymph nodes. ***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**.

Q: Maxillary bone does not articulate with:

Ethmoid. ***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.

Q: What is the typical length of a human sperm cell?

55 micrometers. ***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.

Q: All of the following statements about the third heart sound (S3) are true, except:

Seen in Constrictive Pericarditis. ***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.

Q: What happens to the concentration of inulin as fluid passes through the Proximal Convoluted Tubule (PCT)?

Concentration of inulin increases. ***Concentration of inulin increases*** - Inulin is **freely filtered** at the glomerulus and is neither reabsorbed nor secreted along the renal tubule, making it an excellent marker for **glomerular filtration rate (GFR)**. - As water is reabsorbed from the PCT, the volume of tubular fluid decreases, causing the concentration of **unreabsorbed solutes**, like inulin, to increase. *Concentration of urea remains constant* - Urea is **reabsorbed** along the tubule, though passively; its concentration typically **increases** initially in the PCT due to water reabsorption, but then decreases as some is reabsorbed. - The statement is incorrect because urea concentration changes significantly throughout the nephron, particularly increasing as water is reabsorbed and then decreasing with some reabsorption. *Concentration of HCO3- increases* - The majority (approximately 80-90%) of **bicarbonate (HCO3-)** is reabsorbed in the PCT, primarily through its conversion to CO2 within the tubular lumen and then back to HCO3- intracellularly. - Therefore, the concentration of HCO3- in the tubular fluid actually **decreases** significantly as fluid passes through the PCT. *Concentration of Na+ decreases* - **Sodium (Na+)** is actively reabsorbed along the entire nephron, with about 65-70% reabsorbed in the PCT. - While Na+ is reabsorbed, water follows passively, so its concentration in the tubular fluid remains relatively **iso-osmotic** with plasma, meaning its concentration does not significantly decrease as fluid passes through the PCT, remaining fairly constant.

Q: Which of the following statements is true regarding the function of the spinocerebellar tract?

Smoothens and coordinates movements. ***Smoothens and coordinates movements*** - The spinocerebellar tract provides the cerebellum with **unconscious proprioceptive information** from muscle spindles and Golgi tendon organs. - This information allows the cerebellum to compare intended movements with actual movements, thereby **smoothing and coordinating voluntary motor activity**. *Involved in planning and programming motor activities* - This function is primarily attributed to the **cerebral cortex** (e.g., premotor and supplementary motor areas) and the **basal ganglia**. - While the cerebellum is involved in motor learning and fine-tuning, the initial **planning and programming** of complex movements are cortical functions. *Involved in maintaining equilibrium* - Maintaining equilibrium and balance is primarily a function of the **vestibulocerebellum** (flocculonodular lobe), which receives input from the vestibular system. - While the spinocerebellum indirectly influences balance by coordinating limb movements, its direct role is less pronounced than that of the vestibulocerebellum. *Facilitates learning through vestibulo-ocular reflex changes* - This function is specific to the **vestibulocerebellum** and is crucial for adapting the vestibulo-ocular reflex (VOR) to maintain visual stability during head movements. - The spinocerebellar tract's primary role is proprioception for limb coordination, not VOR adaptation.

Q: In which condition is venous blood most commonly observed to have a high hematocrit in routine clinical practice?

Dehydration. 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].

Q: ANP acts at which site?

Collecting duct. ***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.

Q: Which of the following is most important in sodium and water retention ?

Renin angiotensin system. ***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.

Q: Which tract is responsible for the loss of proprioception and fine touch?

Dorsal column. ***Dorsal column*** - The **dorsal column-medial lemniscus pathway** is responsible for transmitting **fine touch**, **vibration**, and **proprioception** from the body to the cerebral cortex. - Damage to this tract (e.g., in **tabes dorsalis** or **vitamin B12 deficiency**) leads to a loss of these sensations. *Anterior spinothalamic tract* - This tract primarily conveys crude touch and pressure sensations. - While it carries tactile information, it does not transmit the fine discriminative touch or proprioception associated with the dorsal columns. *Lateral spinothalamic tract* - This pathway is responsible for transmitting **pain** and **temperature** sensations. - It does not play a role in proprioception or fine touch. *Corticospinal tract* - The **corticospinal tract** is a **motor pathway** responsible for voluntary movement. - It has no role in transmitting sensory information such as proprioception or fine touch.

Question 1

Lymphatic drainage of cervix is to

Accepted Answer

Iliac lymph nodes

Answer

Para-aortic lymph nodes

Answer

Deep inguinal lymph nodes

Answer

Superficial inguinal lymph nodes

Question 2

Maxillary bone does not articulate with:

Accepted Answer

Ethmoid

Answer

Frontal

Answer

Lacrimal

Answer

Sphenoid

Question 3

What is the typical length of a human sperm cell?

Accepted Answer

55 micrometers

Answer

50 micrometers

Answer

100 micrometers

Answer

65 micrometers

Question 4

All of the following statements about the third heart sound (S3) are true, except:

Accepted Answer

Seen in Constrictive Pericarditis

Answer

Seen in Atrial Septal Defect (ASD)

Answer

Seen in Ventricular Septal Defect (VSD)

Answer

Occurs due to rapid filling of the ventricles during early diastole.

Question 5

What happens to the concentration of inulin as fluid passes through the Proximal Convoluted Tubule (PCT)?

Accepted Answer

Concentration of inulin increases

Answer

Concentration of urea remains constant

Answer

Concentration of HCO3- increases

Answer

Concentration of Na+ decreases

Question 6

Which of the following statements is true regarding the function of the spinocerebellar tract?

Accepted Answer

Smoothens and coordinates movements

Answer

Involved in planning and programming motor activities

Answer

Involved in maintaining equilibrium

Answer

Facilitates learning through vestibulo-ocular reflex changes

Question 7

In which condition is venous blood most commonly observed to have a high hematocrit in routine clinical practice?

Accepted Answer

Dehydration

Answer

Anemia

Answer

Hypervolemia

Answer

Acute blood loss

Question 8

ANP acts at which site?

Accepted Answer

Collecting duct

Answer

Glomerulus

Answer

Loop of Henle

Answer

PCT

Question 9

Which of the following is most important in sodium and water retention ?

Accepted Answer

Renin angiotensin system

Answer

ANP

Answer

BNP

Answer

Vasopressin

Question 10

Which tract is responsible for the loss of proprioception and fine touch?

Accepted Answer

Dorsal column

Answer

Anterior spinothalamic tract

Answer

Lateral spinothalamic tract

Answer

Corticospinal tract

NEET-PG 2012

Anatomy

Internal Medicine

Physiology