Nasal Anatomy and Physiology Flashcards
what is the function of the nasal airway?
humidify and warm inspired air
Remove noxious particles from the air, protects delicate distal lower respiratory tract
what does a blocked nose typically cause?
dry mouth disturbed sleep
what do tracheostomy/laryngectomy patients require?
humidifiers
why is the nose important for olfaction?
Sense organ, housing the olfactory apparatus
Smell substances for pleasure and defence purposes.
Important role in protection from danger, such as fire
Central in forming positive and negative memories
Taste: While chewing, chemicals from food activate olfactory receptors to identify food flavour.
Dysfunction can result poor quality of life
what is choanal atresia?
Choanal atresia is a congenital disorder in which the nasal choanae, (i.e., paired openings that connect the nasal cavity with the nasopharynx), are occluded by soft tissue (membranous), bone, or a combination of both, due to failed recanalization of the nasal fossae during fetal development.
Neonates are obligate nasal breathers
This is an emergency, as neonate will be unable to breathe
Requires surgical repair
what are the four funtions of the nose?
immune
speech
nasal airway
olfaction
what is the immune function of the nose?
Mucus consists of compounds that are able to neutralize antigens
Immunoglobulin A (IgA) and immunoglobulin E (IgE)
Good example is nasal flu vaccine
Smoking reduces number of cilia and change in mucous viscosity.
what are the speech functions of the nose
Nasal airflow modifies speech and produce nasal clicks or click consonants.
Paranasal sinuses also contribute to vocal resonance.
People with blocked nose sound ‘bunged up’
How is the nasal airway able to act as immune barrier?
Specialised nasal mucosal lining
First 1/3 stratified squamous epithelium
Nasal hairs trap large particulates
Posterior 2/3 pseudostratified columnar epithelium
Cilia allows mucus to travel 2.5cm/min
Goblet create sticky mucus that trap pathogens
Mucus contains IgA, IgE (allergies), lysozymes, alkaline
What is the structure of the nasal epithelium?
First 1/3 stratified squamous epithelium
Nasal hairs trap large particulates
Posterior 2/3 pseudostratified columnar epithelium
Cilia allows mucus to travel 2.5cm/min
Goblet create sticky mucus that trap pathogens
Mucus contains IgA, IgE (allergies), lysozymes, alkaline
What does mucus contain?
Mucus contains IgA, IgE (allergies), lysozymes, alkaline
Through what does smell occur?
Olfactory nerve
Through cribrifom plate
Olfactory mucosa
What allows drainage and aeration of middle ear?
Drainage and aeration of middle ear:
Eustachian tube
how is nasal air flow described?
laminar as it enters the nasal vestibule
how does velocity of air change as it travels through nasal valve?
Velocity of the air increases through the nasal valve, the narrowest site of the upper respiratory tract.
what is the function of the paranasal sinuses?
Thye are air filled and arise from the nasal cavity
Reduce skull weight
Physical buffer / crumple zone
Vocal resonance
Humidification
Heat insulation
Immune barrier
What are some of the external subunits of the nose?
Columella
Tip and supratip
Dorsum
Nasion
Glabella
how would you descibe the shape of the external nose?
Visible component of face
Pyramidal shape, with base continuous with forehead and apex at the nasal tip.
what is the dorsum of the nose?
surface between root of nose and tip.
what are the openings of the nose?
nares
what are the nares separated by?
columella
what different components does the nasal skeleton have?
Bony and cartilaginous components
what are the nasal bones?
The internal nasal septum separates the nasal cavity into two nostrils.
The bones that contribute to the nasal septum can be divided into: Paired bones: Nasal, maxillary and palatine bones. Unpaired bones: Ethmoid and vomer bones.
what are the nasal paired bones?
Nasal, maxillary and palatine bones
what are the nasal unpaired bones?
Ethmoid and vomer bones.
what are the two main paired lateral cartilages of the nose?
Upper lateral cartilages
Lower lateral (alar) cartilages
what are the main cartilaes of the nose accompanied by?
Supported by septal cartilage
Smaller minor cartilages
What is the septum formed from?
Bone and cartilage:
Septal cartilage
Vomer
Perpendicular plate of ethmoid
Where does nasal cartilage get blood supply from?
Poor blood supply
Gets blood supply from mucosa overlying it
Relevant in septal haematoma
what is a nasal bone fracture?
Most common facial fracture
Can result in permanent deformity
Possible to correct before bone heals
how is a nasal bone fracture corrected?
Closed reduction of nasal fractures can be performed under local anesthesia in the majority of patients
complication - septal haematoma
What are examples of common nasal trauma?
Broken bones
Move back before they heal
Broken/bent cartilage
Cannot be easily unbent
Septal haematoma - pathology
Septal haematoma = blood collects in the septum
Septal haematoma - aetiology
Post trauma
Septal haematoma - presentation
Almost always bilateral
No blood supply to septum
Causes septum necrosis, leading to perforation so needs to be drained as soon as possible
what is a saddle nose deformity?
Saddle nose deformity refers to a collapsed nasal bridge, which causes the middle portion of your nose to sag
Cartilage has no blood supply of its own
Relies on surrounding perichondrium
Haematoma results in ischaemia and necrosis of the septum
Support to the nose lost
where does the skin of the external nose receive its arterial supply from?
supratrochlear and dorsal nasal arteries (branches of the ophthalmic artery) and infraorbital artery (branch of maxillary artery).
where do the septum and alar cartilages receive their blood supply from
angular artery and lateral nasal artery
what are the angular artery and lateral nasal artery branches of?
Both are branches of the facial artery
where does the vessels from the external nose drain into?
facial vein