NEET-PG 2012 Practice Questions

Q: Cricoid cartilage lies at which vertebral level?

C6. **C6** - The **cricoid cartilage** is an important anatomical landmark, as it signifies the transition from the **laryngopharynx** to the **esophagus** and the start of the **trachea**. - Its location at **C6 vertebral level** is significant for procedures like tracheostomy and in identifying the narrowest part of the adult airway. *C3* - The C3 vertebral level is typically associated with the **hyoid bone**, which is superior to the cricoid cartilage. - The **epiglottis** and the superior aspect of the larynx are more commonly found at C3-C4. *T1* - The T1 vertebral level is in the **thoracic spine**, well below the neck, and is associated with the **apex of the lung** and the **first rib**. - The airway structures at this level are primarily the **trachea** as it enters the thorax. *T4* - The T4 vertebral level is significant as it marks the approximate location of the **carina**, where the trachea bifurcates into the main bronchi. - This level is much lower than the larynx and cricoid cartilage.

Q: Which of the following is a traction epiphysis ?

Coracoid process of scapula. ***Coracoid process of scapula*** - A **traction epiphysis** (also called atavistic epiphysis) serves as an attachment site for muscles and tendons, transferring muscle force to the bone without bearing significant weight or forming articular surfaces. - The **coracoid process** is a classic example, anchoring the **pectoralis minor, coracobrachialis, and short head of biceps brachii**, as well as important ligaments (coracoclavicular and coracoacromial). - It develops from a separate ossification center purely for muscle and ligament attachment, not for articulation or weight-bearing. *Tibial condyles* - The **tibial condyles** are **pressure epiphyses** (articular epiphyses) that form the superior articular surface of the tibia. - They articulate with the femoral condyles to form the knee joint and bear significant weight during standing and movement. - Their primary function is joint formation and contribution to longitudinal bone growth. *Trochanter of femur* - The **greater and lesser trochanters** are large bony prominences that serve as muscle attachment sites, but they are better classified as **apophyses** rather than true traction epiphyses. - An **apophysis** is a secondary ossification center that does not contribute to longitudinal bone growth and serves primarily for muscle attachment. - While functionally similar to traction epiphyses, the term "traction epiphysis" is more specifically applied to structures like the coracoid process, tibial tuberosity, and calcaneal tuberosity. *Head of femur* - The **head of femur** is a classic **pressure epiphysis** that articulates with the acetabulum to form the hip joint. - It bears significant body weight and contributes to the longitudinal growth of the femur. - Its primary functions are joint formation and weight transmission, not muscle attachment.

Q: What anatomical structures are involved in the closure of the fossa ovalis?

Septum primum + Septum secundum. The septum primum acts as a valve, closing against the septum secundum postnatally due to changes in atrial pressure. This fusion effectively closes the foramen ovale, leading to the formation of the fossa ovalis. The endocardial cushions are important for the formation of the atrial and ventricular septa, as well as the AV valves, but not directly for the closure of the fossa ovalis. The septum primum is directly involved, but its apposition with the endocardial cushions doesn't close the foramen ovale. While both structures contribute to heart development, their direct interaction is not responsible for the closure of the fossa ovalis. The septum secundum forms the muscular rim of the fossa ovalis, and the endocardial cushions are critical for atrial septation, but not the final closure here. This option is incorrect because the specific combination of septum primum and septum secundum is indeed responsible for the closure of the fossa ovalis.

Q: Corpora arenacea is seen in?

Pineal. ***Pineal*** - **Corpora arenacea**, also known as **brain sand**, are calcium deposits found in the pineal gland. - Their presence is a normal, age-related finding and increases with age, though their exact physiological role is not fully understood. *Prostate* - The prostate gland contains **corpora amylacea**, which are concentric calcifications found within the glandular acini. - While similar in appearance to corpora arenacea, they are distinct structures specific to the prostate. *Seminal vesicle* - The seminal vesicles produce a fluid component of semen, and while they may occasionally show calcifications, these are typically due to stones or chronic inflammation, not the characteristic "brain sand" seen in the pineal gland. - They do not contain corpora arenacea as a normal physiological feature. *Breast* - Calcifications in the breast are common and can be either benign (e.g., **fibrocystic changes**, vascular calcifications) or malignant (e.g., **ductal carcinoma in situ**). - These calcifications are generally not referred to as corpora arenacea and have different clinical implications and microscopic appearances.

Q: What cofactor is required for the proper functioning of glucose-6-phosphate dehydrogenase?

NADP. ***NADP*** - **NADP+** (nicotinamide adenine dinucleotide phosphate) acts as the **electron acceptor** in the **glucose-6-phosphate dehydrogenase (G6PD)** reaction, becoming **NADPH**. - **NADPH** is crucial for maintaining the **redox balance** in cells, particularly in red blood cells, by reducing **oxidative stress**. *NAD* - **NAD+** (nicotinamide adenine dinucleotide) is a primary cofactor for many **dehydrogenase reactions** in catabolic pathways like **glycolysis** and the **Krebs cycle**. - It primarily functions as an electron acceptor in pathways that generate **ATP**, distinct from the role of **NADPH** in reductive biosynthesis and antioxidant defense. *FAD* - **FAD** (flavin adenine dinucleotide) is a coenzyme derived from **riboflavin (vitamin B2)** that is involved in various redox reactions, often in the form of **flavoproteins**. - Enzymes like **succinate dehydrogenase** in the electron transport chain utilize **FAD** as an electron acceptor, which is not the case for G6PD. *FMN* - **FMN** (flavin mononucleotide) is another coenzyme derived from **riboflavin**, structurally similar to FAD but lacking the additional adenosine monophosphate. - It participates in electron transfer reactions, particularly within **complex I** of the **electron transport chain**, but is not a cofactor for G6PD.

Q: What is the average daily volume of pancreatic secretion in humans?

1.5 L. ***1.5 L*** - The **pancreas** produces approximately **1.5 liters (1200-1500 mL) of pancreatic juice** daily in humans. - This secretion is rich in **digestive enzymes** (amylase, lipase, proteases) and **bicarbonate** for neutralization of gastric acid in the duodenum. - This is the standard value cited in **major physiology textbooks** (Ganong, Guyton & Hall). *2.5 L* - **2.5 liters** overestimates the typical daily pancreatic secretion volume. - This value may represent **combined secretions** from multiple sources or confuse pancreatic output with total upper GI secretions. - Normal pancreatic secretion ranges from **1-2 liters**, making 2.5 L above the physiological range. *5.0 L* - **5.0 liters** represents an abnormally high volume for daily pancreatic secretion alone. - This volume is closer to the **total daily secretions** from stomach, pancreas, and bile combined. - Not consistent with **normal pancreatic physiology**. *10 L* - **10 liters** is grossly excessive for pancreatic secretion and represents approximately the **total volume of all gastrointestinal secretions** (saliva, gastric, pancreatic, bile, intestinal) combined daily. - This is **not physiologically realistic** for pancreatic output alone.

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.

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: Gastric secretions are essential for absorption of -

Cobalamin. ***Cobalamin*** - **Intrinsic factor**, secreted by gastric parietal cells, is crucial for the absorption of **vitamin B12 (cobalamin)** in the terminal ileum [1]. - Without sufficient intrinsic factor, **pernicious anemia** can develop due to impaired B12 absorption [2]. *Fat* - Fat digestion primarily occurs in the **small intestine** with the help of **bile salts** and **pancreatic lipases**. - While gastric lipase begins some fat digestion, it's not essential for overall fat absorption. *Thiamine* - **Thiamine (vitamin B1)** is absorbed in the jejunum and ileum, primarily via **active transport** and passive diffusion. - Gastric secretions do not play a direct, essential role in its absorption. *Folic acid* - **Folic acid** is absorbed in the **duodenum and jejunum** as monoglutamates after being deconjugated from polyglutamate forms. - This process is not directly dependent on gastric secretions [2].

Q: Which of the following hormones does not mediate its action through cAMP?

Estrogen. ***Estrogen*** - **Estrogen** is a **steroid hormone** that mediates its action by binding to intracellular receptors, forming a complex that directly influences gene transcription. - Steroid hormones, due to their **lipophilicity**, can cross the cell membrane and do not typically rely on cell surface receptors or second messengers like cAMP. *Glucagon* - **Glucagon** acts on a **G protein-coupled receptor (GPCR)**, specifically a Gs-coupled receptor, leading to the activation of adenylyl cyclase. - This activation increases the intracellular concentration of **cAMP**, which then activates protein kinase A to mediate its effects, primarily on glucose metabolism. *Follicle stimulating hormone* - **FSH** binds to a **GPCR** on target cells, activating the Gs protein pathway. - This activation stimulates **adenylyl cyclase** and increases intracellular **cAMP** levels, which are critical for its role in gamete development. *Luteinizing hormone* - **LH**, like FSH, binds to a cell surface **GPCR** that activates the Gs protein. - This leads to the stimulation of **adenylyl cyclase** and an increase in **cAMP**, mediating its effects on steroidogenesis and ovulation.

Question 1

Cricoid cartilage lies at which vertebral level?

Accepted Answer

C6

Answer

C3

Answer

T1

Answer

T4

Question 2

Which of the following is a traction epiphysis ?

Accepted Answer

Coracoid process of scapula

Answer

Tibial condyles

Answer

Head of femur

Answer

Trochanter of femur

Question 3

What anatomical structures are involved in the closure of the fossa ovalis?

Accepted Answer

Septum primum + Septum secundum

Answer

Septum primum + Endocardial cushion

Answer

Endocardial cushions + Septum secundum

Answer

None of the options

Question 4

Corpora arenacea is seen in?

Accepted Answer

Pineal

Answer

Seminal vesicle

Answer

Breast

Answer

Prostate

Question 5

What cofactor is required for the proper functioning of glucose-6-phosphate dehydrogenase?

Accepted Answer

NADP

Answer

NAD

Answer

FAD

Answer

FMN

Question 6

What is the average daily volume of pancreatic secretion in humans?

Accepted Answer

1.5 L

Answer

5.0 L

Answer

10 L

Answer

2.5 L

Question 7

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

Question 8

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 9

Gastric secretions are essential for absorption of -

Accepted Answer

Cobalamin

Answer

Fat

Answer

Thiamine

Answer

Folic acid

Question 10

Which of the following hormones does not mediate its action through cAMP?

Accepted Answer

Estrogen

Answer

Glucagon

Answer

Follicle stimulating hormone

Answer

Luteinizing hormone

NEET-PG 2012

Anatomy

Biochemistry

Physiology