Pharynx

What are the main components of the external nose?

The external nose is composed mainly of cartilage and partly of bone, including the nasal bone, frontal process of maxillae, and nasal part of the frontal bone.

• Cartilaginous parts:

➢Septal cartilage

➢Major and minor alar

cartilages

What structures separate the nasal cavities from each other?

The medial wall, or nasal septum, consists of septal nasal cartilage, vomer, and parts of the ethmoid, nasal, frontal, maxillary, palatine, and sphenoid bones.

What forms the floor of the nasal cavities?

• Separates nasal cavities from oral cavity.

• Consists of the hard palate and soft tissues of the external

nose

What is the roof of the nasal cavities composed of?

Separates the nasal cavities from the

cranial cavity.

The roof is formed by parts of the vomer, ethmoid, frontal, nasal, sphenoid, and palatine bones, lateral

processes of septal cartilage, major

alar cartilage and contains the cribriform plate for the olfactory nerve.

What divides each nasal cavity into four air channels?

Lateral wall

• Formed by bone, cartilage and

soft tissue.

The conchae divide each nasal cavity into four air channels (meatus).

Middle and superior concha

formed by medial process of

ethmoid bone.

What are the names of the meatuses in the nasal cavity?

The inferior meatus (between inferior concha and nasal floor), middle meatus (between inferior and middle concha), superior meatus (between middle and superior concha), and spheno-ethmoidal recess (between superior concha and nasal roof).

Paranasal sinuses?

Air-filled cavities around the nasal

cavity.

• Lined by respiratory mucosa.

What are the functions of the paranasal sinuses?

The paranasal sinuses lighten the weight of the head, support immune defense of the nasal cavity, humidify inspired air, and increase resonance of the voice.

What are choanae?

Choanae are openings between the nasal cavities and nasopharynx.

What is the oral cavity ?

The oral vestibule is the space between the dental arches and the deep surfaces of the cheeks and lips.

Oral cavity proper - space enclosed by the dental arches.

• Between the oral fissure (the opening between the lips), &

oropharyngeal isthmus (the opening into the oropharynx).

Teeth and Gums

Teeth - anchored in the jawbones in alveoli. • Gums / Gingiva - made of specialized oral mucosa,

surround and protect teeth and parts of the jawbones.

Cheeks (walls)

Consists of fascia and skeletal

muscle.

• Formed primarily by the

buccinator muscle.

What separates the oral cavity from the nasal cavity?

The hard palate separates the oral cavity from the nasal cavity.

What is the role of the hard palate?

Separates the oral cavity from the nasal

cavity.

• Consists of bone and mucosa.

What is the role of the soft palate?

The soft palate is a muscular structure that lowers to close the oropharyngeal isthmus and elevates to separate the nasopharynx from the oropharynx.

What is the floor of oral region?

Muscular diaphragm - comprised

of bilateral mylohyoid muscles.

• Geniohyoid muscles - pull the

larynx forward during swallowing.

• Tongue.

• Salivary glands.

What is the function of the tongue in the oral cavity?

Muscular organ. • Forms floor of the oral cavity & anterior wall of oropharynx.

The tongue functions in taste perception, swallowing, speech, and maintaining oral hygiene.

Terminal sulcus of tongue

• separates the anterior &

posterior parts.

Superior surface of tongue?

Covered by hundreds of papillae -

Increase area of contact between the

tongue and contents of the oral cavity.

• Have taste buds.

Inferior surface of tongue?

• Frenulum of the tongue

is continuous with mucosa covering the

floor.

Pharyngeal surface of tongue?

Mucosa irregular in

contour.

What are the intrinsic muscles of the tongue?

Originate & attach to other

structures within the tongue.

• Change the shape of the tongue.

• Median sagittal septum.

• 4 pairs:

The intrinsic muscles of the tongue include superior longitudinal, inferior longitudinal, transverse, and vertical muscles, all innervated by the hypoglossal nerve (CN XII).

What are the extrinsic muscles of the tongue and their functions?

The extrinsic muscles include genioglossus -Attaches to mandibular symphysis & inserts on body of

the hyoid bone and length of the tongue (protrudes and depresses), hyoglossus -Arises from the hyoid bone and inserts onto lateral aspect

of the tongue (depresses and retracts), styloglossus -Originates from the styloid process & inserts onto the

lateral aspect of the tongue (retracts and elevates), and palatoglossus -Arises from the palatine aponeurosis and inserts

broadly along the tongue (elevates the posterior tongue), with all innervated by the hypoglossal nerve (CN XII) except palatoglossus (vagus nerve).

What is the blood supply to the tongue?

The blood supply to the tongue comes from the lingual artery and dorsal lingual vein.

What is the primary function of the salivary glands?

Salivary glands produce saliva, which aids in digestion and oral hygiene.

What is the parotid gland's role?

The parotid gland produces serous saliva rich in enzymes and has a duct that routes saliva into the mouth.

Pharynx

Musculofascial tube, connects the nasal and oral cavities to the

larynx and oesophagus.

• Common pathway for air, food and liquids. • Extends from the base of the skull to the cricoid cartilage of the

What are the three regions of the pharynx?

The three regions of the pharynx are the nasopharynx, oropharynx, and laryngopharynx.

Nasopharynx

Continuous with the nasal cavity, behind

the posterior nasal apertures (choanae);

conditions inspired air and propagates it

into the larynx

• Borders: Base of the cranium (superior) &

soft palate (inferior)

How does the nasopharynx function during swallowing?

Opens into the oropharynx through the

pharyngeal isthmus

During swallowing, the soft palate elevates, and the palatopharyngeal sphincter constricts to seal the isthmus, preventing retrograde flow.

Oropharynx

Anterior: the pharyngeal aspect of the

tongue (contains lingula tonsil)

➢ Lateral: marked by the palatopharyngeal

arches and palatine tonsils

➢Posterior: between the body of the second

to the upper part of the third cervical

vertebrae

Oropharynx extension and function with chewing?

xtends from from the soft palate to the upper

margin of the epiglottis, continuous with the

nasal cavity, behind the oropharyngeal

isthmus