Head and Neck: Special Organs in the Head (Nose)

What are the external and internal boundaries of the Nasal Cavity?

External nares / nostrils (provided with hairs / vibrissae); nasal vestibule (just inside nostrils); internal nares

Which duct and spaces open into the Nasal Cavity?

Nasolacrimal ducts and paranasal sinuses (air-filled spaces within bone)

What are the primary functions of the Nasal Cavity?

Passageway of air and sensory receptor for the sense of smell

What structures form the Medial Wall (Nasal Septum) of the nasal cavity?

Perpendicular plate of the ethmoid bone (superior), vomer (inferior), and septal cartilage (anterior)

What structures open into the Superior Meatus of the nasal cavity?

Posterior ethmoidal sinus

What structures open into the Middle Meatus of the nasal cavity?

Anterior ethmoidal sinus, middle ethmoidal sinus, maxillary sinus, and frontal sinus

What structure opens into the Inferior Meatus of the nasal cavity?

Nasolacrimal duct

What bones form the Roof of the nasal cavity?

Cribriform plate of Ethmoid, Nasal, Frontal, and Body of Sphenoid

What bones form the Floor of the nasal cavity?

Palatine process of Maxilla and Horizontal plate of Palatine

What are the primary functions of the Paranasal Sinuses?

Reduce the weight of the skull, produce mucus, and act as voice resonators

What is the status at birth, first radiological evidence, and adult size timeline for the Maxillary Sinus?

Status at birth: Present at birth; First radiological evidence: 4-5 months after birth; Reaches adult size by: 15 years

What is the status at birth, first radiological evidence, and adult size timeline for the Ethmoid Sinus?

Status at birth: Present at birth; First radiological evidence: 1 year; Reaches adult size by: 12 years

What is the status at birth, first radiological evidence, and adult size timeline for the Sphenoid Sinus?

Status at birth: Not present; First radiological evidence: 4 years; Reaches adult size by: 15 years - adult age

What is the status at birth, first radiological evidence, and adult size timeline for the Frontal Sinus?

Status at birth: Not present; First radiological evidence: 6 years; Reaches adult size by: Size increases until teens

A 59-year-old man has mucosal swelling in the superior nasal meatus; which paranasal sinus opening is most likely plugged?

Posterior ethmoidal sinus

What is Epistaxis?

Nosebleed resulting from rupture of the Sphenoido-palatine artery or vessels in Kiesselbach's area

What is Kiesselbach's Plexus / Area, and which arteries converge there?

Anterior nasal septum where branches of Sphenopalatine (Maxillary), Greater Palatine (Maxillary), Anterior Ethmoidal (Ophthalmic), and Superior Labial (Facial) arteries converge

Which artery does NOT contribute to Kiesselbach's plexus?

Lesser palatine artery (Anterior ethmoidal, Sphenopalatine, and Septal branch of Superior Labial do contribute)

What nerve supply innervates the Nasal Cavity?

Branches of olfactory (CN I), anterior ethmoidal branch of ophthalmic (CN V1), and posterior nasal branches of maxillary nerves (CN V2)

Where do the anterior regions of the nasal cavity drain lymphatically?

Forward onto the face by passing around the margins of the nares to submandibular nodes

Where do the posterior regions of the nasal cavity and paranasal sinuses drain lymphatically?

Partly to retropharyngeal nodes and partly to superior deep cervical nodes

What type of epithelium lines most of the nasal cavities and conducting portions?

Ciliated pseudostratified columnar epithelium with a lamina propria containing seromucous glands and lymphoid tissue

What are Ciliated Columnar Cells of the respiratory epithelium and their primary function?

Most abundant cell type; cilia clear microbes and debris

What are the morphological features and function of Goblet Cells in respiratory epithelium?

Features: Basal nuclei and mucin granules; Function: Secrete mucin

What are the morphological features and function of Brush Cells in respiratory epithelium?

Features: Columnar cells with apical microvilli; Function: Chemosensory receptors

What are the morphological features and function of Small Granule / Kulchitsky Cells?

Features: Small cells with numerous granules; Function: Neuroendocrine cells secreting bioactive amines

What is the function of Basal Cells in respiratory epithelium?

Mitotically-active progenitor cells

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

Respiratory epithelium

What are the key histological features of the nasal Lamina Propria?

Rich in venous plexuses over the turbinates and blends with periosteum and perichondrium

What type of epithelium lines the Nasal Vestibule?

Nonciliated cuboidal or columnar epithelium

Where is the Olfactory Epithelium located within the nasal cavity?

Lines the superior conchae at the nasal cavity roof

What type of epithelium is the Olfactory Epithelium?

Thick pseudostratified columnar epithelium

What are Olfactory Neurons?

Bipolar neurons scattered throughout the olfactory epithelium

What are Supporting / Sustentacular Cells in the olfactory epithelium?

Columnar cells with cylindrical apices and microvilli

What are Basal Cells in the olfactory epithelium?

Small, spherical stem cells

What are Olfactory / Bowman Glands, and what is their function?

Serous glands in the lamina propria whose secretions act as a solvent for odoriferous substances

How are the Paranasal Sinuses histologically lined?

Thin respiratory epithelium with fewer goblet cells