Nasal Cavity Structure and Function

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Questions and Answers

Where do the maxillary sinuses drain into the nasal cavity?

Inferior Meatus

Superior Meatus

Hiatus Semilunaris (correct)

Spheno-ethmoidal recess

Which artery supplies blood to the ethmoid sinuses?

Greater Palatine artery

Infraorbital artery

Maxillary artery

Anterior Ethmoid artery (correct)

What is the main nerve that innervates the sphenoid sinuses?

Infraorbital nerve

Posterior Ethmoidal nerve (correct)

Alveolar nerve

Anterior Ethmoidal nerve

Which of the following sinuses is the largest?

Maxillary sinus Signup and view all the answers

Which nerve provides innervation to the maxillary sinus?

Maxillary nerve Signup and view all the answers

Where do the posterior ethmoid sinuses open into the nasal cavity?

Lateral wall of the Superior Meatus Signup and view all the answers

What condition can arise from the spread of an upper respiratory tract infection to the sinuses?

Sinusitis Signup and view all the answers

Which structure is known to drain into the nasal cavity through the hiatus semilunaris?

Both A and B Signup and view all the answers

What is the primary role of the nasal cavity?

Smell, respiration, and speech production Signup and view all the answers

What symptom may result from inflammation of the maxillary sinus?

Toothache Signup and view all the answers

Which of the following sinuses opens at the hiatus semilunaris in the middle meatus?

Anterior ethmoid sinus Signup and view all the answers

Which epithelium lines the vestibular region of the nasal cavity?

Stratified squamous epithelium Signup and view all the answers

What type of cells in the respiratory region secrete mucus?

Goblet cells Signup and view all the answers

Which area of the nasal cavity is responsible for the sense of smell?

Olfactory Region Signup and view all the answers

Which structure divides the nasal cavity into two equal sections?

Nasal septum Signup and view all the answers

What forms the lower front part of the nasal septum?

Quadrangular hyaline cartilage Signup and view all the answers

What is the function of the vibrissae in the nasal cavity?

Filtering large particles from the air Signup and view all the answers

What characterizes the respiratory region of the nasal cavity?

Includes mucus and ciliated epithelium Signup and view all the answers

Which part of the nasal cavity is most exposed to environmental factors?

Vestibule Signup and view all the answers

What structure is NOT part of the respiratory system along with the nasal cavity?

Esophagus Signup and view all the answers

What bones contribute to the roof of the nasal cavity?

Cribriform plate and nasal bones Signup and view all the answers

Which structure separates the nasal cavity from the oral cavity?

Hard palate Signup and view all the answers

What is NOT a function attributed to the paranasal sinuses?

Increasing the sense of smell Signup and view all the answers

Which of the following pairs includes all the named paranasal sinuses?

Frontal and maxillary Signup and view all the answers

Which of the following is true regarding the connection between the nasal and oral cavities?

The nasopharynx connects both cavities. Signup and view all the answers

Where can openings to the paranasal sinuses typically be found?

On the roof and lateral walls of the nasal cavity Signup and view all the answers

What type of epithelium lines the paranasal sinuses?

Ciliated pseudostratified epithelium Signup and view all the answers

Which of the following correctly describes the frontal sinuses?

They are the most superior sinuses. Signup and view all the answers

Which bone does NOT form part of the posterior border of the nasal cavity?

Temporal bone Signup and view all the answers

What is the primary role of the soft palate and uvula during eating?

To prevent food entry into the nasal cavity Signup and view all the answers

Study Notes

The Nasal Cavity

Structure: The nasal cavity is the interior of the nose, located behind the nostrils.
Function: Responsible for smell, respiration, and speech production.
Vestibule: The area just posterior to the nostrils, lined with multiple layers of stratified squamous epithelium. It contains stiff hairs called vibrissae covered in thick mucus.
Respiratory Region: Extends from the vestibule and includes the entire nasal cavity, apart from the olfactory region. It is lined with ciliated pseudostratified epithelium containing goblet cells which secrete mucus.
Olfactory Region: Located at the top of the nasal cavity near the septum. It is lined with olfactory cells and olfactory mucosa containing cilia with olfactory receptor proteins responsible for the sense of smell.

Walls and Boundaries of the Nasal Cavity

Medial Wall: The septum divides the cavity into two equal sections. The upper and lower parts of the septum are formed by the perpendicular plate of the ethmoid bone and the vomer. The lower front part is formed by a quadrangular hyaline cartilage structure called the septum cartilage.
Superior Border (Roof): Formed by nasal bones, the lower part of the frontal bone, the cribiform plate of the ethmoid bone, and the sphenoid bone.
Lateral Wall: Formed by the lower parts of the nasal bones, attached cartilage, the outer nose, and the nostrils.
Posterior Border (Back Wall): Bordered by the maxilla, ethmoid bone, palatine bone, sphenoid bone, lacrimal bone, and the inferior concha.
Floor: Formed by the hard palate, composed of the palatine process of the maxilla and the palatine bones. The floor separates the nasal cavity from the oral cavity.
Nasopharynx: The nasal and oral cavities connect via the nasopharynx at the back of the throat. The soft palate and uvula close off this connection during eating preventing food from entering the nasal cavity.

The Paranasal Sinuses

Definition: Air-filled extensions of the nasal cavity.
Types: Four sinuses – maxillary, frontal, sphenoid, and ethmoid – named after the bone they are located in.
Lining: Each sinus is lined with ciliated pseudostratified epithelium containing mucus-secreting goblet cells.
Function: Lightening the weight of the head, supporting nasal cavity immune defence, humidifying inspired air, and increasing voice resonance.

Paranasal Sinus Locations & Drainage

Frontal Sinuses: Two located within the frontal bone, most superior of the sinuses. They are roughly triangular in shape and drain via the frontonasal duct, which opens into the hiatus semilunaris within the middle meatus of the nasal cavity.
Sphenoid Sinus: Located within the sphenoid bone and drain into the nasal cavity in an area superior and posterior to the superior concha known as the spheno-ethmoidal recess.
Ethmoid Sinuses: Found within the ethmoid bone.
- Anterior: Open onto the hiatus semilunaris (middle meatus)
- Middle: Opens onto the lateral wall of the middle meatus.
- Posterior: Opens onto the lateral wall of the superior meatus.
Maxillary Sinuses: Largest of the sinuses, located laterally and slightly inferior to the nasal cavity. They drain into the nasal cavity via the hiatus semilunaris underneath the frontal sinus opening.

Clinical Relevance of the Paranasal Sinuses

Sinusitis: An upper respiratory tract infection can spread to the sinuses causing inflammation and pain.
Toothache: The maxillary nerve supplies both the maxillary sinus and maxillary teeth. Inflammation of the maxillary sinus can present as toothache.

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Description

This quiz explores the anatomy and functions of the nasal cavity, including its various regions such as the vestibule, respiratory region, and olfactory region. Test your knowledge on the structure, boundaries, and role of the nasal cavity in respiration and smell.