NEET-PG 2015 - Anatomy Practice Questions

Q: Elastic fibers of tunica media are secreted by

Smooth muscle. Correct: Smooth muscle - Smooth muscle cells within the tunica media are primarily responsible for synthesizing and secreting elastic fibers along with collagen and proteoglycans [1] - This extracellular matrix provides elasticity and structural integrity to blood vessels, allowing them to stretch and recoil with blood flow [1] - In elastic arteries (like the aorta), smooth muscle cells produce fenestrated elastic membranes that are characteristic of the tunica media Incorrect: Endothelium - Endothelial cells form the innermost lining of blood vessels (tunica intima) and are involved in regulating vascular tone, blood clotting, and inflammation [1] - They do not typically secrete the bulk of elastic fibers found in the tunica media Incorrect: External lamina - The external lamina (or external basal lamina) is an extracellular matrix layer, not a cellular component that secretes elastic fibers - It is actually secreted by the smooth muscle cells themselves and serves as structural support around individual muscle cells Incorrect: Fibroblast - Fibroblasts are connective tissue cells that primarily produce collagen and other extracellular matrix components in many tissues - While they contribute to the tunica adventitia (outermost layer), the tunica media's elastic fibers are primarily produced by smooth muscle cells [1]

Q: Lens is attached to ciliary body via?

Zonular fibers. ***Zonular fibers*** - The **suspensory ligaments** of the lens, known as zonular fibers (or **Zonules of Zinn**), connect the lens capsule to the ciliary body. - These fibers play a crucial role in **accommodation** by transmitting the tension from the ciliary muscle to the lens, causing it to change shape [2]. *Limbus* - The **limbus** is the junction between the cornea and the sclera, serving as a transitional zone [3]. - It does not directly attach the lens to the ciliary body but is an important anatomical landmark for eye surgery. *Vitreous Humour* - The **vitreous humor** is the clear, gel-like substance that fills the space between the lens and the retina [4]. - It maintains the shape of the eye and holds the retina in place, but it does not provide structural attachment for the lens. *Root of iris* - The **root of the iris** is the outermost part of the iris where it attaches to the ciliary body. - While it is adjacent to the ciliary body, it is the iris structure itself and does not serve to attach the lens [1].

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: 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: External auditory canal is formed by:

1st branchial groove. 1st branchial groove - The **external auditory canal** is primarily derived from the **first branchial (pharyngeal) groove** during embryonic development [1]. - This groove deepens to form the primitive external auditory meatus, which later develops into the adult external auditory canal [1]. *1st visceral pouch* - The **first pharyngeal (visceral) pouch** gives rise to structures like the **eustachian tube** (auditory tube) and the **middle ear cavity** (tympanic cavity) [1]. - It does not contribute to the formation of the external auditory canal. *2nd branchial groove* - The **second pharyngeal (branchial) groove** contributes to the formation of the **cervical sinus**, which normally obliterates. - Persistence of this groove can lead to **cervical cysts or fistulae**, but it is not involved in ear development. *2nd visceral pouch* - The **second pharyngeal (visceral) pouch** develops into the **palatine tonsils** and its fossa. - It plays no role in the formation of the external auditory canal or other ear structures.

Q: Which anatomical structure lies between the bulla ethmoidalis and the uncinate process of the ethmoid?

Ethmoidal infundibulum. ***Ethmoidal infundibulum*** - The **ethmoidal infundibulum** is a curved, three-dimensional space located within the **lateral wall of the nasal cavity**. - It forms a critical drainage pathway, often leading to the opening of the **maxillary sinus** and serving as the primary outflow tract for the anterior ethmoidal air cells. *Bulla ethmoidalis* - The **bulla ethmoidalis** is the largest and most constant anterior ethmoid air cell, bulging into the middle meatus. - It lies *superior and posterior* to the ethmoidal infundibulum, forming one of its boundaries, not the space itself. *Uncinate process of ethmoid* - The **uncinate process** is a sickle-shaped bony lamella that forms the *anterior and inferior boundary* of the ethmoidal infundibulum. - It helps define the pathway for drainage but is a bony structure, not the intervening space. *Maxillary sinus* - The **maxillary sinus** is a paranasal sinus located within the maxilla, which drains into the posterior part of the ethmoidal infundibulum or hiatus semilunaris. - It is a separate air-filled cavity, not the anatomical space between the bulla ethmoidalis and uncinate process.

Q: What lies between the middle and inferior turbinate?

Middle meatus. ***Middle meatus*** - The **nasal meatuses** are passages in the nasal cavity that lie inferolateral to a corresponding **turbinate**. - Therefore, the **middle meatus** is located directly beneath the **middle turbinate** and superior to the **inferior turbinate**. *Superior meatus* - The **superior meatus** lies below the **superior turbinate**. - It drains the posterior ethmoid air cells and the sphenoid sinus. *Hiatus semilunaris* - The **hiatus semilunaris** is a curved opening located within the **middle meatus**. - It is an important drainage pathway for the frontal sinus, maxillary sinus, and anterior ethmoid air cells. *Inferior meatus* - The **inferior meatus** lies below the **inferior turbinate**. - It receives the opening of the **nasolacrimal duct**.

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: In a patient with chronic sinusitis, which of the following structures is associated with the presence of ethmoidal bullae?

Anterior ethmoidal air cells. ***Anterior ethmoidal air cells*** - The **ethmoidal bulla** is the largest and most constant **anterior ethmoidal air cell**, located in the lateral wall of the middle meatus. - It is a key component of the **ostiomeatal complex** and its inflammation or blockage can contribute to chronic sinusitis by obstructing drainage pathways. - The ethmoidal bulla drains into the **middle meatus** via the hiatus semilunaris and is positioned superior to the uncinate process. *Posterior ethmoidal air cells* - These are located more posteriorly and drain into the **superior meatus**, not the middle meatus where the ethmoidal bulla drains. - The posterior cells are separated from the anterior cells by the **basal lamella of the middle turbinate. - The **ethmoidal bulla** is an anterior structure, clearly distinguished from the posterior ethmoidal cell group. *Superior ethmoidal air cells* - This is **not a standard anatomical classification** for ethmoidal air cells. - The ethmoid labyrinth is divided into **anterior and posterior groups**, not superior/inferior or middle classifications. - The ethmoidal bulla belongs to the anterior ethmoid complex. *Inferior ethmoidal air cells* - This is **not a recognized anatomical classification** for ethmoidal air cells. - Standard classification divides ethmoidal cells into **anterior** (including the bulla) and **posterior** groups. - The ethmoidal bulla is specifically an anterior ethmoidal air cell, the largest of this group.

Q: What is the type of epithelium of the adenoid?

Pseudostratified ciliated columnar epithelium. ***Pseudostratified ciliated columnar epithelium*** - The adenoid (pharyngeal tonsil) is located in the nasopharynx, which is part of the upper respiratory tract and is lined with **pseudostratified ciliated columnar epithelium** with goblet cells [1]. - This type of epithelium is also known as **respiratory epithelium**, and its cilia and mucus-producing goblet cells help to trap and clear inhaled particles and pathogens [1]. *Non-keratinized squamous epithelium* - This type of epithelium is found in areas subject to friction and abrasion, such as the oral cavity, oro- and laryngopharynx, and esophagus, not typically in the nasopharynx. - It provides protection but lacks the ciliated and mucus-producing cells necessary for clearing respiratory passages. *Cuboidal epithelium* - This epithelium is typically found in glands and ducts, secretory and absorptive surfaces, such as renal tubules and thyroid follicles. - It does not have the specialized functions (cilia, mucus production) required for the respiratory system's protective lining. *Columnar epithelium with goblet cells* - While the adenoid epithelium does contain **goblet cells** for mucus production, specifically stating "columnar epithelium" is not as precise as "pseudostratified ciliated columnar epithelium." - The key feature of being **pseudostratified** and **ciliated** is crucial for its function in the nasopharynx [1].

Question 1

Elastic fibers of tunica media are secreted by

Accepted Answer

Smooth muscle

Answer

Endothelium

Answer

External lamina

Answer

Fibroblast

Question 2

Lens is attached to ciliary body via?

Accepted Answer

Zonular fibers

Answer

Limbus

Answer

Vitreous Humour

Answer

Root of iris

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

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 5

External auditory canal is formed by:

Accepted Answer

1st branchial groove

Answer

1st visceral pouch

Answer

2nd branchial groove

Answer

2nd visceral pouch

Question 6

Which anatomical structure lies between the bulla ethmoidalis and the uncinate process of the ethmoid?

Accepted Answer

Ethmoidal infundibulum

Answer

Bulla ethmoidalis

Answer

Uncinate process of ethmoid

Answer

Maxillary sinus

Question 7

What lies between the middle and inferior turbinate?

Accepted Answer

Middle meatus

Answer

Superior meatus

Answer

Inferior meatus

Answer

Hiatus semilunaris

Question 8

What is the narrowest part of the nasal cavity?

Accepted Answer

Internal nasal valve area

Answer

Vestibule

Answer

Choanae

Answer

Inferior turbinate

Question 9

In a patient with chronic sinusitis, which of the following structures is associated with the presence of ethmoidal bullae?

Accepted Answer

Anterior ethmoidal air cells

Answer

Posterior ethmoidal air cells

Answer

Superior ethmoidal air cells

Answer

Inferior ethmoidal air cells

Question 10

What is the type of epithelium of the adenoid?

Accepted Answer

Pseudostratified ciliated columnar epithelium

Answer

Non-keratinized squamous epithelium

Answer

Cuboidal epithelium

Answer

Columnar epithelium with goblet cells

NEET-PG 2015 — Anatomy