NEET-PG 2013 Practice Questions

Q: Which of the following is a cerebellar nucleus?

Fastigial nucleus. ***Fastigial nucleus*** - The **fastigial nucleus** is one of the four principal deep cerebellar nuclei, involved in regulating **balance** and **posture** [2]. - The deep cerebellar nuclei are crucial for the cerebellum's output, relaying processed information to other brain regions [2]. *Caudate nucleus* - The **caudate nucleus** is part of the **basal ganglia**, a group of subcortical nuclei in the forebrain [1]. - It plays a significant role in **motor control**, learning, memory, and reward processing. *Subthalamic nucleus* - The **subthalamic nucleus** is a small nucleus located in the **diencephalon**, below the thalamus and above the substantia nigra [1]. - It is also part of the **basal ganglia system** and is critical for modulating motor control [1]. *Putamen* - The **putamen** is another structure belonging to the **basal ganglia**, located in the forebrain [1]. - It is primarily involved in regulating various types of **motor behavior** and learning.

Q: Which thalamic nuclei can produce basal ganglia symptoms?

Ventral anterior. ***Ventral anterior*** - The **ventral anterior (VA)** and **ventral lateral (VL)** nuclei of the thalamus receive significant input from the **basal ganglia** and project to the motor cortex [1]. - Dysfunction in these nuclei can disrupt the basal ganglia's influence on motor control, leading to symptoms like **dyskinesia** or **rigidity** [1]. *Lateral dorsal* - The **lateral dorsal nucleus** is primarily involved in **limbic system** functions and episodic memory. - It does not have direct nor significant connections with the basal ganglia motor circuits that would produce typical basal ganglia symptoms. *Pulvinar* - The **pulvinar** is the largest thalamic nucleus, primarily involved in **visual processing**, attention, and eye movements. - While it has extensive cortical connections, it is not directly involved in the motor circuits of the basal ganglia. *Intralaminar* - The **intralaminar nuclei** (e.g., centromedian and parafascicular) receive input from the basal ganglia but primarily project diffusely to the cerebral cortex and are involved in **arousal** and consciousness [2]. - While they modulate cortical activity, their dysfunction typically wouldn't produce the classic motor symptoms associated with basal ganglia disorders.

Q: Which part of the heart is located in the anterosuperior sternal region?

Right ventricle.. ***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].

Q: Sacral promontory is the landmark for

Termination of presacral nerve. ***Termination of presacral nerve*** - The **sacral promontory** is the key anatomical landmark where the **superior hypogastric plexus** (presacral nerve) **bifurcates** into the right and left hypogastric nerves. - This bifurcation typically occurs at the level of the **sacral promontory**, making it a crucial landmark for **presacral neurectomy** procedures. - The superior hypogastric plexus is formed by the fusion of sympathetic fibers and lies anterior to the L5 vertebra and sacral promontory. - Clinically important for **pelvic surgery** and **pain management** procedures. *Origin of superior mesenteric artery* - The **superior mesenteric artery (SMA)** originates from the **anterior aspect of the abdominal aorta** at the level of the **L1 vertebra**. - This is far superior to the sacral promontory, which is at the lumbosacral junction (L5-S1). - The SMA supplies the midgut derivatives. *Origin of inferior mesenteric artery* - The **inferior mesenteric artery (IMA)** originates from the **anterior aspect of the abdominal aorta** at the level of the **L3 vertebra**. - This is also well above the sacral promontory. - The IMA supplies the hindgut derivatives. *None of the options* - This is incorrect as the sacral promontory is indeed a recognized landmark for the **bifurcation/termination of the presacral nerve** (superior hypogastric plexus).

Q: Which of the following statements about the linea aspera is correct?

Continues as gluteal tuberosity. Correct: Continues as gluteal tuberosity - The lateral lip of the linea aspera continues superiorly as the gluteal tuberosity (also called the gluteal ridge or line) - This anatomical continuation is a key feature of the femur's posterior surface - The gluteal tuberosity serves as the attachment site for the gluteus maximus muscle - The medial lip continues superiorly as the pectineal line (spiral line), which then joins the lesser trochanter Incorrect: Forms lateral border of femur - The linea aspera is located on the posterior surface of the femoral shaft, not on the lateral border - The lateral border of the femur is formed by the smooth lateral surface of the shaft - The linea aspera's lateral lip is a posterior ridge, distinct from the true lateral border Incorrect: Forms medial border of femur - The linea aspera is on the posterior aspect of the femur, not the medial border - The medial border of the femur is formed by the smooth medial surface of the shaft - The medial lip of the linea aspera is a muscle attachment site on the posterior surface, not a border

Q: What is a cochleate uterus?

Acute anteflexion. ***Acute anteflexion*** - A **cochleate uterus** describes a uterus with an **acute anteflexion**, meaning it is sharply bent forward at the junction of the cervix and the body of the uterus. - This anatomical variation can sometimes be associated with **dysmenorrhea** or difficulty with **intrauterine device (IUD) insertion**. *Large uterus* - A large uterus, also known as **uteromegaly**, is a general descriptive term for an enlarged uterus, which can be due to various causes such as **fibroids** or **adenomyosis**, and is not specific to an acute anteflexion. - It does not directly describe the acute angulation that defines a cochleate uterus. *Acute retroflexion* - **Acute retroflexion** refers to a uterus that is sharply bent backward at the level of the cervix. - This is the opposite of **anteflexion**, which describes a forward bend, and therefore is not a cochleate uterus. *Large cervix* - A **large cervix** describes an enlarged uterine cervix, which is the lower, narrow part of the uterus. - This typically relates to conditions like **cervical hypertrophy** or **nabothian cysts** and is distinct from the overall angulation of the uterine body in relation to the cervix.

Q: All of the following are true regarding fibromuscular dysplasia EXCEPT:

OCPs predispose. ***OCPs predispose*** - **Oral contraceptive pills (OCPs)** are not identified as a predisposing factor for fibromuscular dysplasia (FMD). FMD is largely considered a sporadic condition with some genetic predisposition, but not linked to OCP use [1]. - While hormonal influences are suspected given its higher prevalence in women, direct causation or exacerbation by OCPs has not been established [1]. *Medium size vessels are affected* - Fibromuscular dysplasia (FMD) predominantly affects **medium-sized arteries**, most commonly the renal and carotid arteries [1]. - This involvement leads to characteristic stenoses, aneurysms, or dissections in those vessels. *Aneurysm may occur* - The abnormal arterial wall architecture in FMD, characterized by alternating areas of stenosis and dilation, can lead to the formation of **aneurysms**. - These aneurysms are usually **intracranial** or within the affected renal and carotid arteries, and represent a significant risk of rupture or dissection. *Irregular hyperplasia* - FMD involves **irregular fibrous or fibromuscular hyperplasia** of the arterial wall layers (intima, media, or adventitia). - This abnormal cellular proliferation and connective tissue deposition result in the characteristic "string of beads" appearance on angiography. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 493-494.

Q: What is the most important extracellular buffer?

Bicarbonates. ***Bicarbonates*** - The **bicarbonate buffer system** is the most important extracellular buffer because its components (carbonic acid and bicarbonate) are present in high concentrations and their levels can be regulated by both the lungs (CO2 excretion) and the kidneys (bicarbonate reabsorption/secretion). - Its pKa (6.1) makes it an effective buffer against metabolically produced acids, which frequently challenge blood pH. *Phosphate buffer* - The **phosphate buffer system** is more important as an intracellular buffer and in renal tubular fluid due to its higher concentration in these compartments. - Its concentration in the extracellular fluid is relatively low compared to bicarbonate, limiting its capacity as the primary extracellular buffer. *Plasma protein buffer* - **Plasma proteins**, particularly albumin, have numerous ionizable groups and contribute to buffering in the extracellular fluid. - However, their overall buffering capacity is less significant than that of the bicarbonate system due to lower concentration compared to bicarbonate and less dynamic regulation. *Ammonium buffer* - The **ammonium buffer system** (ammonia/ammonium) is primarily important for acid-base regulation by the kidneys, where it plays a critical role in excreting excess acid, particularly in chronic acidosis. - It is not a major extracellular fluid buffer in the systemic circulation under normal physiological conditions.

Q: All should be features of a substance to measure GFR, except?

Freely reabsorbed. ***Freely reabsorbed*** - A substance used to measure GFR should **not be reabsorbed** by the kidney tubules. If it were reabsorbed, the amount excreted in the urine would be less than the amount filtered, leading to an **underestimation of GFR**. - The ideal GFR marker is **neither reabsorbed nor secreted**, ensuring that its excretion rate directly reflects the filtration rate. *Freely filtered across the glomerulus membrane* - For a substance to accurately measure GFR, it must be **freely filtered** from the blood into the Bowman's capsule, without any restriction due to its size or charge. - This ensures that its concentration in the glomerular filtrate is the same as in the plasma, allowing for a direct calculation of the filtration rate. *Not secreted by kidney* - An ideal GFR marker should **not be secreted** by the renal tubules, as active secretion would add to the amount excreted in the urine, leading to an **overestimation of GFR**. - This property, along with not being reabsorbed, ensures that the amount of the substance appearing in the urine solely reflects the amount filtered. *None of the options* - This option is incorrect because there is a definitive feature listed among the choices that is *not* a characteristic of an ideal GFR marker. The ability to be "freely reabsorbed" is a disqualifying trait.

Q: Which type of nerve fibers are responsible for carrying joint position and vibration sense?

A-beta fibers. ***A-beta fibers*** - **A-beta fibers** are **large-diameter, myelinated** sensory fibers that conduct impulses rapidly. - They are primarily responsible for transmitting **light touch, pressure, joint position (proprioception), and vibration sense**. - **This is the correct answer** because A-beta fibers carry **BOTH joint position AND vibration sense together**. *A-alpha fibers* - **A-alpha fibers** are the **largest and fastest** conducting nerve fibers. - They include **motor nerves to skeletal muscles** and **sensory fibers from muscle spindles (Ia) and Golgi tendon organs (Ib)**. - While Ia fibers (A-alpha) do carry **proprioception from muscle spindles**, they do **NOT carry vibration sense**. - The question asks for fibers carrying **BOTH** joint position **AND** vibration sense, making A-beta the correct answer. *C fibers* - **C fibers** are **small-diameter, unmyelinated** nerve fibers with **slow conduction velocities**. - They are responsible for transmitting **dull, aching pain, temperature, and crude touch**. *A-delta fibers* - **A-delta fibers** are **small-diameter, thinly myelinated** nerve fibers with an intermediate conduction velocity. - They primarily transmit **sharp, fast pain** and **cold temperature sensations**.

Question 1

Which of the following is a cerebellar nucleus?

Accepted Answer

Fastigial nucleus

Answer

Putamen

Answer

Caudate nucleus

Answer

Subthalamic nucleus

Question 2

Which thalamic nuclei can produce basal ganglia symptoms?

Accepted Answer

Ventral anterior

Answer

Lateral dorsal

Answer

Pulvinar

Answer

Intralaminar

Question 3

Which part of the heart is located in the anterosuperior sternal region?

Accepted Answer

Right ventricle.

Answer

Right atrium and auricle.

Answer

Left atrium.

Answer

Left ventricle.

Question 4

Sacral promontory is the landmark for

Accepted Answer

Termination of presacral nerve

Answer

None of the options

Answer

Origin of inferior mesenteric artery

Answer

Origin of superior mesenteric artery

Question 5

Which of the following statements about the linea aspera is correct?

Accepted Answer

Continues as gluteal tuberosity

Answer

Forms lateral border of femur

Answer

Forms medial border of femur

Answer

None of the options

Question 6

What is a cochleate uterus?

Accepted Answer

Acute anteflexion

Answer

Large uterus

Answer

Acute retroflexion

Answer

Large cervix

Question 7

All of the following are true regarding fibromuscular dysplasia EXCEPT:

Accepted Answer

OCPs predispose

Answer

Medium size vessels are affected

Answer

Aneurysm may occur

Answer

Irregular hyperplasia

Question 8

What is the most important extracellular buffer?

Accepted Answer

Bicarbonates

Answer

Phosphate buffer

Answer

Plasma protein buffer

Answer

Ammonium buffer

Question 9

All should be features of a substance to measure GFR, except?

Accepted Answer

Freely reabsorbed

Answer

Not secreted by kidney

Answer

Freely filtered across the glomerulus membrane

Answer

None of the options

Question 10

Which type of nerve fibers are responsible for carrying joint position and vibration sense?

Accepted Answer

A-beta fibers

Answer

A-alpha fibers

Answer

C fibers

Answer

A-delta fibers

NEET-PG 2013

Anatomy

Obstetrics and Gynecology

Pathology

Physiology