NEET-PG 2015 - Anatomy Practice Questions

Q: Which is the narrowest portion of the esophagus?

At the cricopharyngeal sphincter. ***At the cricopharyngeal sphincter*** - This is the **upper esophageal sphincter (UES)**, representing the **narrowest point of the entire esophagus** with a diameter of approximately **14 mm**. - It is formed by the **cricopharyngeus muscle**, which remains tonically contracted at rest to prevent air entry into the esophagus during respiration. - Located approximately **15 cm from the incisor teeth** at the level of the **C6 vertebra**. - **Clinical significance**: This is the most common site for impaction of foreign bodies and is a critical point during endoscopy. *At the crossing of the left main bronchus* - This represents the **middle constriction** where the esophagus is indented by the **left main bronchus** (approximately 22-23 cm from incisors). - This is a point of **extrinsic compression** rather than an intrinsic anatomical narrowing. - Diameter here is approximately **15.5 mm**, making it wider than the upper esophageal sphincter. - Foreign bodies and food boluses may lodge here, but it is not the narrowest point. *At the level of the aortic arch* - The **aortic arch** causes significant indentation and extrinsic compression, adjacent to the bronchial constriction. - This is also part of the **middle constriction** of the esophagus. - Despite this indentation, the lumen diameter is still greater than at the cricopharyngeal sphincter. *At the diaphragmatic aperture* - The esophagus passes through the **esophageal hiatus** at the level of **T10 vertebra** (approximately 40 cm from incisors). - This represents the **lower constriction** with a diameter of approximately **16-19 mm**. - While clinically important for hiatal hernias and lower esophageal sphincter pathology, it is the **widest of the three anatomical constrictions**.

Q: What is the narrowest part of the nasal cavity?

Internal nasal valve area. ***Internal nasal valve area*** - The **internal nasal valve** (ostium internum) is the **narrowest part of the nasal cavity**, located approximately 1.3 cm from the nostril - Formed by the **septal cartilage medially**, **upper lateral cartilage laterally**, **nasal floor inferiorly**, and **anterior head of inferior turbinate posteriorly** - The angle between the septum and upper lateral cartilage is typically **10-15 degrees**, creating the narrowest cross-sectional area - Accounts for approximately **50% of total nasal airway resistance** and is clinically the most critical site for airflow regulation - **Clinical significance**: Site of nasal valve collapse in breathing disorders *Vestibule* - The **nasal vestibule** is the most anterior part of the nasal cavity lined with **keratinized stratified squamous epithelium** and **vibrissae** (nasal hairs) - While it is a narrow region, it is **NOT the narrowest part** of the nasal cavity - Acts as the entrance to the nasal cavity but has a larger cross-sectional area than the internal nasal valve *Choanae* - The **choanae** are the **posterior openings** of the nasal cavity that open into the nasopharynx - They represent a transition point for airflow but are relatively **wide openings**, not the narrowest part *Inferior turbinate* - The **inferior turbinate** is a bony projection covered with erectile tissue that increases surface area for warming and humidifying air - While it can become engorged and narrow the airway pathologically, anatomically it does not constitute the narrowest fixed point of the nasal passage

Q: Ceruminous glands present in the ear are:

Modified apocrine glands. ***Modified apocrine glands*** - **Ceruminous glands** in the ear canal are specialized **apocrine glands** responsible for producing cerumen (earwax). - Like other apocrine glands, they secrete their product via **apical budding** of the cell, releasing fragments of the cell along with the secretion [1]. *Modified eccrine glands* - **Eccrine sweat glands** are distributed throughout the skin and produce a watery sweat for thermoregulation [1]. - They secrete their product directly onto the skin surface via **exocytosis**, without loss of cellular material. *Mucous gland* - **Mucous glands** (e.g., salivary glands, respiratory tract glands) produce **mucus**, a viscous secretion primarily for lubrication and protection. - Their secretions are rich in **mucin glycoproteins**, which is distinct from the lipid-rich cerumen. *Modified holocrine glands* - **Holocrine glands** (e.g., sebaceous glands) release their entire cell contents, including lipids and cellular debris, upon cell lysis. - While sebaceous glands contribute to earwax, ceruminous glands themselves operate via an **apocrine mechanism**, not holocrine [1].

Q: Where is the auditory cortex primarily located in the brain?

Superior temporal gyrus. ***Superior temporal gyrus*** - The **primary auditory cortex** (Brodmann areas 41 and 42) is located in the **superior temporal gyrus**, primarily within the **transverse temporal gyri of Heschl**. [1] - This region is responsible for processing **auditory information**, including pitch, loudness, and sound localization. [1] *Inferior temporal gyrus* - The **inferior temporal gyrus** is a part of the temporal lobe involved in higher-level **visual processing** and object recognition. - It plays a role in the "what" pathway of vision and **memory formation**, not primary auditory processing. *Area 3,1,2* - **Brodmann areas 3, 1, and 2** collectively form the **primary somatosensory cortex**. [2] - This area is located in the **postcentral gyrus** of the parietal lobe and is responsible for processing touch, pain, temperature, and proprioception. [2] *Cingulate gyrus* - The **cingulate gyrus** is a component of the **limbic system**, involved in emotion formation, learning, memory, and executive function. - It plays a role in processing emotional aspects of pain and fear, but not primary auditory perception.

Q: Anterior tonsillar pillar is formed by?

Palatoglossal fold. Palatoglossal fold - The palatoglossal fold (anterior faucial pillar) is formed by the mucous membrane covering the palatoglossus muscle. - It defines the anterior boundary of the tonsillar fossa, hence forming the anterior tonsillar pillar. - Clinical relevance: This landmark is important during tonsillectomy and for identifying peritonsillar abscess location. Palatopharyngeal fold - This fold is formed by the mucous membrane covering the palatopharyngeus muscle. - It forms the posterior boundary of the tonsillar fossa, thus being the posterior tonsillar pillar (posterior faucial pillar). Pterygopalatine arch - This is not a recognized anatomical structure related to the tonsillar region. - The term appears to conflate "pterygopalatine fossa" (a skull space) with the palatine arches (tonsillar pillars), making it an effective distractor. Valleculae - The valleculae are depressions located between the base of the tongue and the epiglottis. - They are part of the laryngopharynx involved in swallowing and are not associated with the tonsillar pillars.

Q: When does the rudimentary cochlea develop in the fetus?

4th to 8th week. 4th to 8th week - The **cochlea** begins its development from the **otic vesicle** around the **4th week** of gestation and undergoes extensive coiling. - By the **8th week**, the cochlea has achieved its characteristic snail-like shape, though further differentiation and maturation continue. *First week* - The first week of embryonic development involves **fertilization**, **cleavage**, and **implantation**, with no organogenesis occurring [1]. - At this stage, the embryo is a **blastocyst**, and specific organ structures like the cochlea have not yet begun to form [1]. *8th to 12th week* - While significant maturation of the inner ear structures occurs during this period, the **rudimentary cochlea** has already formed its basic shape by the 8th week. - This phase involves further differentiation of the **organ of Corti** and development of neural connections, rather than the initial formation of the cochlea itself. *16 to 20th week* - By the 16th to 20th week, the inner ear structures are largely developed and functional, including the **cochlea**, which is capable of responding to sound stimuli. - This period marks the onset of **fetal hearing** and continued fine-tuning of the auditory system, far beyond the rudimentary stage of cochlear development.

Q: Which area in the spleen is considered *primarily* thymus-dependent?

Periarteriolar lymphoid sheath (PALS). ***Periarteriolar lymphoid sheath (PALS)*** - PALS is the **T-cell zone** of splenic white pulp, containing predominantly **T-lymphocytes** arranged around central arterioles. [2] - This area is **thymus-dependent** as it houses mature T cells that have undergone thymic selection and education, making it the primary thymus-dependent area of the spleen. [1] *Mantle layer* - The mantle layer consists of **naïve B lymphocytes** that surround the germinal center within splenic follicles. - This area is **thymus-independent** and primarily involved in **B-cell responses** to antigens. *Malpighian corpuscle* - Also known as **splenic follicles** or white pulp, this area primarily functions as **B-cell aggregation zones**. - While containing both B and T cell areas, it's predominantly **thymus-independent** with its main role being B-cell activation and antibody production. *None of the options* - This option is incorrect because PALS clearly represents the primary **thymus-dependent area** in the spleen. - The spleen definitively contains thymus-dependent zones where **T-cell activation** and proliferation occur, specifically the PALS. [1]

Q: Which of the following statements about the bare area of the liver is false?

It is circular in shape. ***It is circular in shape*** - The bare area of the liver is **triangular** in shape, bordered by the reflections of the **coronary ligaments** and the inferior vena cava. [1] - Its shape is dictated by the anatomical arrangement of these peritoneal folds, making it distinctly non-circular. *Infection can spread from the abdominal to thoracic cavity at this area* - This statement is true because the bare area is the only part of the liver not covered by **peritoneum**, allowing direct contact between the liver and the diaphragm. [1] - This anatomical arrangement facilitates the spread of infections, like **subphrenic abscesses**, from the abdominal cavity to the posterior mediastinum and pleural cavity. [2] *It is not a site of portocaval anastomosis* - This statement is true; there is **no direct portosystemic shunt** at the bare area of the liver that becomes significant in portal hypertension. - While small veins connect the liver capsule to the diaphragm, these do not represent major portocaval anastomoses like those found at the gastroesophageal junction or rectum. *Formed by the reflections of coronary ligaments* - This statement is true; the bare area is specifically demarcated by the points where the **anterior and posterior layers of the coronary ligament** diverge, leaving a triangular region of the liver directly apposed to the diaphragm. [1] - The **coronary ligaments** are reflections of the peritoneum from the diaphragm onto the superior surface of the liver.

Q: Food can commonly get obstructed in the esophagus at all of the following locations except

Crossing of the hemiazygous vein. Food can commonly get obstructed in the esophagus at all of the following locations except ***Crossing of the hemiazygous vein*** - The **hemiazygos vein crosses the vertebral column** at T7-T9 to drain into the azygos vein; however, this anatomical relationship does not typically create a constriction or point of obstruction for the esophagus. - While it is in proximity, its course does not physically compress or narrow the esophageal lumen in a manner that would commonly cause food impaction. *Crossing of left bronchus* - The **left main bronchus crosses anterior to the esophagus** at the level of the carina (T4-T5), causing a natural indentation and narrowing of the esophageal lumen. - This anatomical narrowing, coupled with the rigid structure of the bronchus, makes it a common site for food impaction, especially for larger boluses. *Crossing of arch of aorta* - The **arch of the aorta crosses anterior and to the left of the esophagus** at the level of T3-T4, creating another significant anatomical constriction. - This bending and compression by a large, typically pulsatile vessel forms a natural bottleneck where swallowed food can easily become lodged. *Diaphragmatic aperture* - The **esophageal hiatus of the diaphragm** (T10) is the most distal natural esophageal narrowing, where the esophagus passes through a muscular opening before joining the stomach. - This narrow opening, surrounded by the crura of the diaphragm, is a very common site for food impaction, particularly when the opening is physiologically or pathologically narrowed (e.g., in cases of hiatal hernia or tight diaphragmatic attachments).

Question 1

Which is the narrowest portion of the esophagus?

Accepted Answer

At the cricopharyngeal sphincter

Answer

At the diaphragmatic aperture

Answer

At the crossing of the left main bronchus

Answer

At the level of the aortic arch

Question 2

What is the narrowest part of the nasal cavity?

Accepted Answer

Internal nasal valve area

Answer

Vestibule

Answer

Choanae

Answer

Inferior turbinate

Question 3

Ceruminous glands present in the ear are:

Accepted Answer

Modified apocrine glands

Answer

Modified eccrine glands

Answer

Mucous gland

Answer

Modified holocrine glands

Question 4

Where is the auditory cortex primarily located in the brain?

Accepted Answer

Superior temporal gyrus

Answer

Inferior temporal gyrus

Answer

Area 3,1,2

Answer

Cingulate gyrus

Question 5

Anterior tonsillar pillar is formed by?

Accepted Answer

Palatoglossal fold

Answer

Palatopharyngeal fold

Answer

Pterygopalatine arch

Answer

Valleculae

Question 6

What is the significance of the term 'Corona mortis' in human anatomy?

Accepted Answer

Anastomosis between obturator and inferior epigastric vessels

Answer

Anastomosis between superior and inferior gluteal arteries

Answer

A ligament connecting the pubic symphysis

Answer

A nerve crossing the pelvic brim

Question 7

When does the rudimentary cochlea develop in the fetus?

Accepted Answer

4th to 8th week

Answer

First week

Answer

8th to 12th week

Answer

16 to 20th week

Question 8

Which area in the spleen is considered *primarily* thymus-dependent?

Accepted Answer

Periarteriolar lymphoid sheath (PALS)

Answer

Mantle layer

Answer

Malpighian corpuscle

Answer

None of the options

Question 9

Which of the following statements about the bare area of the liver is false?

Accepted Answer

It is circular in shape

Answer

It is not a site of portocaval anastomosis

Answer

Formed by the reflections of coronary ligaments

Answer

Infection can spread from the abdominal to thoracic cavity at this area

Question 10

Food can commonly get obstructed in the esophagus at all of the following locations except

Accepted Answer

Crossing of the hemiazygous vein

Answer

Crossing of left bronchus

Answer

Crossing of arch of aorta

Answer

Diaphragmatic aperture

NEET-PG 2015 — Anatomy