Nasal Cavity, Paranasal Sinuses, Nasopharynx Flashcards
What is respiration?
Exchange of oxygen from environment to cells for utilisation and removal of CO2
3 stages of gas exchange?
1= ventilation (moving gas to site of exchange)
2= gas exchange (capillary beds at lungs and tissues)
3= cellular respiration (cells use oxygen in biochemical processes)
What are the 8 functions of the respiratory system?
- warm, humidify and filter inhaled air
- pH balance
- primarily gas exchange
- speech/vocalisation
- protect and maintain itself from the rest of the body
- prostaglandin synthesis
- metabolic function (angiotensin 1 to angiotensin 2)
Why is there a thin walled and a selectively permeable membrane in the respiratory system?
To facilitate diffusion
What does the moist membrane help to facilitate?
Oxygen and co2 can be dissolved in water to facilitate diffusion
Describe how/why the system work autonomously?
- effective monitoring and feedback mechanisms
- has to be able to do so it can function voluntarily for desired increased and decreased rates
Conducting portion of the respiratory system?
- nose
- nasal cavity
- parasternal sinus
- pharynx
- larynx
- trachea
- bronchi
- bronchial trees
- terminal bronchials
Respiratory portion?
- respiratory bronchioles
- alveoli (ducts and sacs)
How are the alveoli made for optimal gas exchange?
- 400 million per lung
- large surface area
- rich vascular supply
What makes up the upper respiratory tract?
1) nose (nasal cavity)
2) nasopharynx
What makes up the lower respiratory tract?
1) larynx
2) trachea
3) bronchial tree
4) alveolar ducts
5) alveolar sac
6) pulmonary alveoli
What is the nasal cavity held open by?
Held open by a box made of bone and cartilage (osteocartilaginous)
Why is bone needed to hold the nasal cavity open?
Because the decreasing intrathoracic pressure on inhalation would result in the nasal cavity closing if it was held open by cartilage
What are the anterior openings supported by?
Cartilage
What are the 3 muscles around the nostrils (nasal muscles)?
1) procerus
2) nasalis
3) levator labii superioris alaeque nasi
What is the functions of the nasal muscles?
1) acts as sphincters or dilators
2) controls the diameter of the nares and adjusts air flow
THEY ARE MUSCLES OF FACIAL EXPRESSION
What are the nasal muscles innervated by?
Facial nerve
Where is the nasal vestibule?
Immediately after passing the nostrils
What is the nasal vestibule lined with?
Squamous mucosa Epithelium which has VIBRISSAE
Function of vibrissae
First air filters in the respiratory system
The nasal vestibule is at risk of what?
Nasal vestibulitis caused by S.aureus
What does the nasal septum act as?
What does the nasal septum consist of?
1- acts as a medial wall in the nasal cavity, diving it into right and left nasal fossa
2- the nasal septum consists of bone posterior lay and cartilage anterior lay
What are the 2 bones of the septum?
Vomer and ethmoid
Describe the position and nasal cavity is covered in?
It is posterior to the nose and the bony structures are converted in respiratory mucosa
Floor of the nasal cavity made from?
Hard and soft palate
Lateral wall of the nasal cavity is made from what?
- Ethmoid
- superior and middle conchae
- inferior nasal conchae
- maxilla
- sphenoid
- palatine bone
- lacrimal
- nasal bone
What is hard palate made from?
Palatine process maxilla
Horizontal plate of palatine bone
What are the 4 bones of the roof of the nasal cavity?
What mucosa is on the nasal cavity?
1- nasal bone
2- frontal bone
3- ethmoid bone
4- sphenoid bone
Specialised olfactory mucosa
What are the 2 bones of the floor of the nasal cavity?
1- palatine bones
2- maxilla bone
THESE MAKE UP THE HARD PALATE
What makes up the roof of the mouth
Frontal bone
Ethmoid bone
Cribiform plate
sphenoid
Specialised olfactory mucosa
What makes up the medial wall of the nasal cavity?
- septal cartilage
- ethmoid (perpendicular plate)
- vomer
What is the structure called in the middle of the ethmoid bone?
Cribiform plate
- civ like
- this is how the olfactory nerves go from the anterior cranial fossa to the nasal cavity.
What are nasal conchae?
They are pairs of bones that project from the lateral wall of the nasal cavity like shelves
What do conchae produce/
Passages between the inferior surface of the concha and the lateral wall called the meatus.
What are concha with mucus membranes known as?
Turbinates
What type of epithelium will you find in the nasal cavity?
Mostly respiratory
Also
Olfactory
What is NALT?
Where would you find it?
Nasal associated lymphoid tissue
Situated at the superior aspect of the nasopharynx with tonsils
Wha type of epithelium do you find in the superior turbinate?
Olfactory mucosa
What type of epithelium do you find between middle turbinate and inferior turbinate?
Respiratory mucosa
What are the 2 purposes of conchae?
1- increase surface area for humidifying or cooling air
2- form air channels (meatuses)
What drains into meatuses?
Parasternal sinuses and nasolacrimal duct
What are the 5 gateways in the nasal cavity?
1- foramen caecum
2- cribiform plate
3- sphenopalatine foramen
4- small foramina in the lateral wall
5- incisive canal
Describe respiratory mucosa?
- ciliates pseudostratified columnar epithelium
- goblet cells
- rich vascular supply and submucosal glands
What is the olfactory nerve an extension of?
Cranial nerve 1
What are the right and left olfactory tracts an extension of?
Forebrain extension
Describe the passage from the olfactory mucosa to the brain?
1- olfactory mucosa
2- olfactory nerves (passing through cribiform plate)
3- olfactory tract
4- medial and lateral striae
5- pisiform cortices
What passes through the foramen caecums?
What bone is it found on?
emissary vein connecting nasal veins with superior sagital sinus
Found on the ethmoid bone
Where is a potential tract for infection from the nasal cavity to the cranial cavity?
Foramen caecum
Where is the cribiform late found?
What passes through the cribiform plate?
1- ethmoid bone
2- olfactory nerves
(Note that there is an adjacent foramina for anterior ethmoidal nerve and vessels
Where is the sphenopalatine foramen located?
What passes through here?
1- between the sphenoid and palatine bone
2- sphenopalatine artery
Nasopalatine nerve
Superior nasal nerve
What structures pass out the incisive canal?
Nasopalatine artery
Greater palatine nerve
What are the 3 main arteries in the nasal cavity?
1- internal carotid
2- external carotid
3- facial artery
1- What is the main nasal branch of the internal carotid?
2- what is the main nasal branch of the external carotid?
1- Ophthalmic artery
2- maxillary artery
What are the 2 branches of the ophthalmic artery?
What are each of its branches?
Anterior ethmoidal …. External nasal
Posterior ethmoidal … septal branches
What are the branches of the maxillary artery?
What are its branches?
Sphenopalatine…. Posterior lateral nasal and posterior septal
Descending palatine … greater palatine
What is the main branch of the facial artery?
What are its branches?
Superior labial …. Lateral and septal nasal arteries
Kiesselbach area?
Site of apistaxis
Describe the venous drainage of the nasal cavity?
Where are the 3 places all the veins drain into?
- veins accompany arteries
- all of the veins will drain into the Cavernous Sinus via superior ophthalmic or…
- Pterygoid plexus
- facial vein
What are the:
Anterior
Posterior
Deep lymph nodes?
Anterior = submandibular nodes
Posterior = retropharyngeal nodes
Deep = cervical nodes
What lymph nodes will be palpable if they are inflamed?
Jugulodigastric node
What are the 2 divisions of the trigeminal nerve?
Ophthalmic (V1)and maxillary (V2) divisions
V1 - ophthalmic, what are its 3 branches?
1- nasociliary nerve
2- anterior ethmoidal
3- (lateral and septal) nasal branches
V2-, what are the 2 divisions of the maxillary division?
1- Nasopalatine
2- greater palatine
What is the 3rd other innervation?
CN1 - special sensory from olfactory epithelium
Form to function- why are the nasal cavities main fnctions and how are they good at it?
- turbinates aid in warming and humidifying air
- large surface area
- well vascularised
- generate turbinate flow which aids in filtering particles before they pass further into the airway, this is called “turbulent precipitation.”
- mucus and cilia clear trapped particles
What is the effect of smoking on the cilia hair and what is the effect of stopping smoking?
Smoking will impair ciliary function
People who stop smoking will probably cough more after due increasing function of the cilia.
What are the 4 paranasal sinuses?
1- frontal sinus
2- ethmoid sinus
3- maxillary sinus
4- sphenoid sinus
What is the name of each sinus in this picture?
Green = frontal sinus
Purple = ethmoidal cells
Blue = maxillary sinus
Red = sphenoid sinus
What are paranasal cavities?
What are their functions?
What do they drain into?
- they are epithelium lined cavities within facial bones around the nasal cavities
- they lighten the skull, aid in warming and humidifying air
- they all drain into the lateral aspect of the nasal cavity.
What is the maxillary sinus particularly prone too?
Why?
Sinusitis
Because the osteom/communications with the middle meatus is high superiorly on the medial wall of the sinus so it doesn’t favour sinus drainage.
Frontal sinus will drain into where?
Frontal sinus nerve and artery supply?
Ethmoidal infundibulum (middle meatus) via the frontonasal duct
Nerve = supraorbital (CNV1)
ARTERY = Anterior ethmoidal (branch of ophthalmic)
Where will the sphenoidal sinus drain to?
Nerve and artery supply?
- spheno-ethmoidal recess
- nerve = posterior ethmoidal (nasociliary from CN V1)
Orbital branches of CN V2 from pterygopalatine ganglion
Artery = pharyngeal arteries (branch of maxillary)
Where will the anterior, middle and ethmoidal cells drain too?
What is their nerve and artery innervation?
Anterior = ethmoidal infundibulum
Middle = middle meatus
Posterior = superior
Nerve = Anterior and Posterior ethmoidal nerve (nasociliary from CN V1)
Orbital Branches CN V2 from pterygopalatine ganglion
Artery = Anterior and Posterior Ethmoidal (ophthalmic)
Where will the maxillary sinus drain into?
Nerve and artery innervation?
- middle meatus via the semilunar hiatus
Nerve = infra orbital and superior alveolar branches of the maxillary nerve (CN V2)
Artery = infra orbital and superior alveolar branches of the maxillary artery
Where does the pituitary gland sit?
In the hypofosseal fossa, directly above the sphenoidal sinus
Nasopharynx
1- What is it the first part of?
2- What does it communicate with?
3- What does it become?
4- What is its functions?
5- what is its innervation?
1- first part of pharynx
2- communicates with nasal cavity via choanae
3- becomes oropharynx below soft palate
4- air conduit
5- sensory innervation from pharyngeal branch of CNV2 (trigeminal nerve branch)
Function of conchae?
What 3 structures make up the conchae?
They serve as a connection between the nasal cavity and the nasopharynx
1- horizontal plate of palatine bone
2- medial plate of pterygoid process
3- vomer
What is the pharyngotympanic tube?
This is a tube that extends from the tympanic tube in the ear to the pharynx
It is a cartilaginous tube with muscular attachment covered by mucosa
(Connects lateral wall of the nasal pharynx to the middle ear)
How is the pharyngotympanic tube linked to air travel?
During air travel, swallowing, eating or squeezing our nose will increase intra thoracic pressure.
By doing this we are opening the pharyngotympanic tube, allowing air to go into the ear cavity and equalise the pressure between the internal and external environment of the ear drum causing relief.
Describe the structure of the pharyngotympanic tube and the muscles that arise from it?
What are the 2 muscles of the pharyngeal opening and what happens when they contract?
The structure of the tube is musculocartilaginous, with muscle laterally and cartilage medially
Muscles:
- salpingopharyngeus (goes to pharynx)
- tensor veil palatini (goes to soft palate)
- levator palatini (goes to soft palate)
1- salphingopharyngeus
2- tensor veli palatini
When either muscle contracts, this will produce a sufficient positive pressure in the oral cavity, so the air will open this opening and flow into the middle ear cavity
Tonsil tissue:
What is it?
How many different types do we have?
What are the collectively called?
Tonsils are lymphoid tissue that are important in immune surveillance
2x tubal tonsils (nasopharynx) = nasal cavity
1x pharyngeal (adenoid) (most superior) = nasal cavity
2x palatine (back of throat) = oral cavity
1x lingual (most inferior) = oral cavity
Waldeyer’s ring = a ring of protective tissue around the opening to airway and GI tract
Define pneumatization?
Small nasal cavity outgrowths at birth grow by a process called pneumatization.
Describe the position and what the pharyngeal recess if?
Is it also known as Rossenmuller
- deep recess posterior to opening of pharyngotympanic tube
- most common site of pharyngeal carcinoma
What will develop in the pharyngeal recess/
Adenohypophysis (anterior lobe of the pituitary gland)
This is also called Rathke’s pouch (an embrylogical ingavination)
What can cause mouth breathing?
What can this lead to?
Inflammation and swelling of the pharyngeal tonsil may obstruct the airway and lead to mouth breathing.
This can lead to adenoid face which refers to the atypical appearance of the facial features and can result from persistent adenoid hypertrophy.
What can enlargement of the tubal tonsil do?
Enlargement of the tubal tonsil may obstruct the pharyngotympanic tube and cause middle ear infections.
Describe the special and somatic sensory innervation of the nasal cavity?
Special sensory will be supplied by CN1- the olfactory nerve to the olfactory epithelium which is in the superior portion of the nasal cavity.
The opthalmic and maxillary divisions of trigeminal nerve will have somatic sensory innervation.
The opthalmic divisions supply the anterior superior portion and the maxillary division supplies the posterior inferior portion of the nasal cavity.
