Nasal And Oral Cavities Flashcards
Semilunar hiatus
a crescent-shaped groove in the lateral wall of the nasal cavity just inferior to the ethmoidal bulla. It is the location of the openings for the frontal sinus, maxillary sinus, and anterior ethmoidal sinus.
Nasal cavity is split into
Left and right nasal cavities form first part of respiratory tract
Separated by a thin midline septum - formed of cartilage and bone
What separates the oral cavity and nasal cavity
Hard palate (floor of nasal cavity)
What separates the brain and nasal cavity
Bone (the roof of the nasal cavity)
Cribriform plate
Midline nasal septum
Cartilage anteriorly
Superior part of posterior septum = perpendicular plate of ethmoid bone
Inferior part of posterior septum = vomer bone
3 projections of bone on lateral wall of nasal cavity
Superior, middle and inferior conchae
What are the spaces inferior to the conchae
The superior, middle and inferior meatuses
What is the function of the meatuses
Inspired air is warmed, humidified and filtered
Cribriform plate
Delicate section of bone perforated with tiny holes
Separates nasal cavity and cranium
Olfactory nerves from the olfactory receptors in the mucosa of the upper part of the nasal cavity travel through the perforations to the brain
Arterial supply of the nasal cavity
Several arteries including branches of the maxillary artery which is a terminal branch of the external carotid artery
Blood supply to the nasal septum
An anastomotic network formed supplies this nasal cavity
Often site of bleeding in a nosebleed (epistaxis)
Innervation of the nose
Sensory via branches of the trigeminal nerve (CN V)
4 paranasal sinuses
Frontal
Ethmoid
Sphenoid
Maxillary
Where is the frontal sinuses
Lie within the anterior part of the frontal bone
Where is the ethmoid sinus
Air cells lie within the ethmoid bone (superior to the nasal cavity and medial to the orbits)
Where are the sphenoid sinuses
Lie within the sphenoid bone
Where are the maxillary sinuses
Lie within the maxillae of the facial skeleton
Lateral to the lateral walls of the nasal cavity
Where does the frontal sinus drain into
Middle meatus
Where does the sphenoid sinus drain into
Spheno-ethmoidal recess
Where do the ethmoid air cells drain into
Superior and middle meatuses
Where does the maxillary sinus drain into
Middle meatus
(opening into the middle meatus lies superomedially, therefore it cannot drain feely when the head is upright)
Nasolacrimal duct
Drains fluid that lubricates the anterior surface of the eye into nasal cavity
Opens into inferior meatus
Middle ear
Small cavity within the temporal bone that is modified for hearing
Contains 3 tiny bones that transmit sound waves to the inner ear
Eustachian tube
Auditory tube connects middle ear to nasopharynx
Opening seen on lateral wall of nasopharynx surrounded by tonsillar tissue (which forms a slight bulge)
Function of auditory tube
Allows air to pass into the middle ear so that the pressure on either side of the tympanic membrane (eardrum) is equal - important for optimal conduction of sound waves
Tympanic membrane
Eardrum
Lies between the middle and external ear
The palate
Composed of hard (anteriorly of bone) and soft (posteriorly of muscle) palate
Forms roof of oral cavity
Hard palate
Composed of palatine processes of the maxillae and horizontal plates of the palatine bone
Function of hard palate
Prevents food or fluid entering the nasal cavity
Push our tongue against hard palate during first phase of swallowing which forces food and fluid backwards into the oesophagus
Push tongue against hard palate to articulate certain sounds
Cleft palate
Palate does not form properly during embryological development
Causes difficulty with eating, swallowing and speech if not repaired
Soft palate
Posterior to hard palate
Composed of several muscles
Uvula
Midline conical projection which hangs from the posterior border of the soft palate
Innervation of soft palate
Vagus nerve (CN X)
Function of soft palate
Muscles contract during swallowing which elevated the soft palate closing the nasopharynx from the oral cavity - prevents reflux of food and fluid into nasal cavity
Superior boundary of oral cavity
Hard and soft palate (roof of the mouth)
Inferior border of the oral cavity
Soft tissues and muscles (floor of the mouth)
Lateral borders of the oral cavity
Cheeks which contain the buccinator muscle
What does the oral cavity contain
Tongue
Teeth
Gums
Opening of salivary ducts
How many teeth do adults have
32
-16 embedded in the maxilla (upper jaw) and 16 in the mandible (lower jaw)
Different types of teeth
In the upper and lower jaws there are:
4 incisors
2 canines
4 premolars
6 molars
What are teeth composed of
An inner pulp which contains blood vessels and nerves
Dentin surrounding the pulp
An outer hard coating of enamel
Erosion of enamel and dentin
Caused by bacteria or foodstuffs
Can lead to decay, inflammation, infection of the pulp (which a]can spread to the bone and lead to abscess formation)
Papillae
Located on superior surface on tongue
Detect taste
Vallecula
Space between the posterior tongue and anterior aspect of the epiglottis
Location of tongue
anterior part of the tongue lies in the oral cavity, and the posterior part (the root) extends into the oropharynx
motor Innervation of intrinsic and extrinsic muscles of tongue
Hypoglossal nerve (CN XII)
Intrinsic tongue muscles
Lie within the tongue
Paired bilaterally and fuse in the midline
Change the shape of the tongue
Extrinsic tongue muscle
Attached to the tongue but originate from outside it in the mandible and hyoid bone
Move the tongue
How many nerves control sensory Innervation of the tongue
3:
Facial nerve
Trigeminal nerve
Glossopharyngeal nerve
Facial nerve (CN VII)- tongue
Taste in anterior 2/3
Trigeminal nerve (CN V)- tongue
General sensation (touch, pain, temperature) in anterior 2/3
Glossopharyngeal nerve (CN IX)- tongue
Taste and general sensation in posterior 1/3
Arterial supply of oral cavity
Lingual, maxillary and facial arteries (branches of external carotid artery)
Location of pharyngeal tonsil (adenoid)
Roof and posterior wall of nasopharynx
Location of tubal tonsil
Surrounds opening of auditory tube on lateral wall of nasopharynx
Location of palatine tonsil
Lateral walls of oropharynx (visible when mouth open)
Location of lingual tonsil
Collection of lymphoid tissue in the posterior tongue
3 pairs of salivary glands
Parotid
Submandibular
Sublingular
What is glandular secretion stimulated by
Parasympathetic fibres
Parotid gland
Largest of glands
Overlies posterior part of mandible- basically in cheek
Saliva empties into the mouth via the parotid duct, which opens adjacent to the upper 2nd molar tooth
Closely related to external carotid artery
Parotid gland and facial nerve
After the nerve exits the skull, it enters the deep surface of the parotid gland. Within the gland the facial nerve divides into five branches which emerge to innervate the muscles of facial expression.
Innervation of parotid gland
Parasympathetic fibres in the Glossopharyngeal nerve
Submandibular glands
Smaller than parotid glands
Lie inferior to body of mandible, just anterior to the angle
Opens into the floor of the mouth, under the tongue
Innervation of submandibular gland
Parasympathetic fibres in facial nerve
Sublingual glands
Lie in floor of mouth
Open via several small ducts into floor of the mouth
Innervation of sublingual glands
Parasympathetic fibres in facial nerve
where does the parotid duct open into the oral cavity near
the upper 2nd molar tooth
Why does heat cause a nosebleed
Vasodilation of capillaries causing them to burst
How many teeth do adults have
32
