The Nasal Cavity & Paranasal Sinuses

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which structure primarily divides the nasal cavity into two equal sections?

Olfactory mucosa

Vestibule

Vibrissae

Septum (correct)

What type of epithelium lines the vestibule of the nasal cavity?

Ciliated simple columnar epithelium

Stratified cuboidal epithelium

Stratified squamous epithelium (correct)

Simple squamous epithelium

What structure separates the nasal cavity from the oral cavity?

Nasal bones

Cribriform plate

Soft palate

Hard palate (correct)

Which region of the nasal cavity contains goblet cells that secrete mucus?

Respiratory region Signup and view all the answers

What role do olfactory receptor proteins primarily serve in the nasal cavity?

Detect smell Signup and view all the answers

Which of the following bones contribute to the roof of the nasal cavity?

Frontal bone Signup and view all the answers

What are the primary functions of the paranasal sinuses?

Lightening the weight of the head Signup and view all the answers

Which of the following components is NOT part of the respiratory system structure that includes the nasal cavity?

Olfactory bulbs Signup and view all the answers

What is the clinical significance of the nasal cavity's protective layer?

Protects against pathogens Signup and view all the answers

Which sinus is located within the sphenoid bone?

Sphenoid sinus Signup and view all the answers

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

They close off the nasal cavity connection Signup and view all the answers

Which of the following accurately describes the structure known as the septum cartilage?

Hyaline cartilaginous structure in the nasal septum Signup and view all the answers

What is the primary sensory function of the nasal cavity?

Detecting smells Signup and view all the answers

What type of epithelium lines the paranasal sinuses?

Ciliated pseudostratified epithelium Signup and view all the answers

Which sinuses drain back into the nasal cavity?

All paranasal sinuses Signup and view all the answers

What is the significance of the cribiform plate in the nasal cavity?

It contains olfactory bulbs Signup and view all the answers

What is the main anatomical location for drainage of the frontal sinuses?

Hiatus Semilunaris Signup and view all the answers

Which artery supplies blood to the sphenoid sinuses?

Pharyngeal branches of the maxillary arteries Signup and view all the answers

Which nerve innervates the anterior ethmoid sinuses?

Nasociliary nerve Signup and view all the answers

What is the consequence of an upper respiratory tract infection in relation to the paranasal sinuses?

It can cause inflammation and pain, known as sinusitis. Signup and view all the answers

Where do the maxillary sinuses drain into the nasal cavity?

Hiatus Semilunaris Signup and view all the answers

Which of the following sinuses is the largest?

Maxillary sinuses Signup and view all the answers

Which structure provides the primary pathway for fluid drainage from the frontal sinus to the maxillary sinus?

Hiatus Semilunaris Signup and view all the answers

The posterior ethmoid sinuses drain into which part of the nasal cavity?

Lateral wall of the superior meatus Signup and view all the answers

Study Notes

Nasal Cavity

The Nasal Cavity is the interior of the nose, responsible for smell, respiration and speech production.
The Vestibule is the area just inside the nostrils, lined by stratified squamous epithelium for protection.
The Vestibule contains stiff hairs called Vibrissae to capture debris.
The Respiratory region, lined with ciliated pseudostratified epithelium, contains goblet cells that secrete mucus for the mucous membrane.
The Olfactory Region, located at the top by the septum, houses olfactory cells and mucosa, containing receptor proteins for smell.
The Medial Wall of the nasal cavity is the septum which divides the nasal cavity into two sections.
The septum is formed from the perpendicular plate of the ethmoid bone, the vomer bone and the septal cartilage.
The Superior border (roof) of the nasal cavity is made of the nasal bone, frontal bone, cribiform plate and sphenoid bone.
The Anterior border (lateral wall) is formed by the lower nasal bones, cartilage, outer nose and nostrils.
The Posterior border (back wall) of the nasal cavity is made up of the maxilla, ethmoid bone, palatine bones, sphenoid bone, lacrimal bone and the inferior concha.
The Floor of the nasal cavity is the inferior concha which separates the nasal cavity from the oral cavity.
The hard palate, formed by the palatine process of the maxilla and the palatine bones, also contributes to the separation of the nasal and oral cavities.
The nasal and oral cavities are connected through the Nasopharynx.
The soft palate and uvula help close off the connection during eating to prevent food entry.

Paranasal Sinuses

Four paranasal sinuses (maxillary, frontal, sphenoid and ethmoid) are air-filled extensions of the nasal cavity.
The sinuses are named according to the bone they are located in.
They are lined with ciliated pseudostratified epithelium and contain mucus.
Potential functions of the paranasal sinuses: lighten the weight of the head, support the immune defense of the nose, humidify inspired air, and increase resonance of the voice.
The paranasal sinuses are formed during development as the space between the nasal cavity and the surrounding bones erodes.
All sinuses drain back into the nasal cavity.
Sinuses have openings on the roof and lateral walls of the nasal cavity.

Frontal Sinuses

There are two frontal sinuses, superiorly located in the frontal bone.
They are roughly triangular in shape.
Drainage is via the Frontonasal duct into the Hiatus Semilunaris on the Middle meatus of the nasal cavity.
They are innervated by the Supraorbital nerve (branch of the Ophthalmic).
The blood supply is by the Anterior Ethmoid artery (branch of the Internal Carotid).

Sphenoid Sinuses

Found in the Sphenoid bone.
They open into the nasal cavity in the Spheno-ethmoidal recess, superiorly and posteriorly to the Superior Concha.
Innervation: Posterior Ethmoidal nerve (branch of the Ophthalmic), branches of the maxillary nerve.
Blood supply: Pharyngeal branches of the maxillary arteries.

Ethmoid Sinuses

There are 3 ethmoid sinuses within the ethmoid bone: anterior, middle and posterior.
The anterior ethmoid sinues open into the Hiatus Semilunaris (Middle Meatus).
The middle ethmoid sinuses open onto the lateral wall of the Middle Meatus.
The posterior ethmoid sinuses open onto the lateral wall of the Superior Meatus.
Innervation: Anterior & Posterior Ethmoid branches of the Nasociliary nerve, maxillary nerve.
Blood supply: Anterior and Posterior Ethmoid arteries.

Maxillary Sinuses

The largest of the sinuses and located laterally and inferior to the nasal cavity.
They drain into the nasal cavity via the Hiatus Semilunaris, underneath the Frontal Sinus opening.
This route can allow for spread of infection as fluids from the Frontal Sinus can enter the maxillary sinus.
Innervation: Branches of the Alveolar Nerve and the Infraorbital Nerve.
Blood supply: Branches of Alveolar Arteries plus Infraorbital and Greater Palatine Arteries.

Clinical Relevance

Sinusitis, an inflammation of the sinus caused by upper respiratory tract infections, can occur as the sinuses are connected to the nasal cavity.
The maxillary nerve supplies the maxillary sinus and the maxillary teeth, and inflammation of the sinus can affect the teeth.