Module 2 Respiratory Flashcards
Skull osteology
Ethmoid bone - Superior midline nasal septum
Frontal bone - Front of head
Mandible - Jaw
Maxilla - Lower mouth and Above mouth
Sphenoid bone - Behind the eyes and nose
Nasal bones - Top of nose
Occipital bone - Back of head
Palatine bones - Back of mouth
Parietal bones - Top of head
Temporal bones - Bottom of skull
Vomer - inferior midline nasal septum
Zygomatic bones - outside cheeks
GEM Upper Respiratory Tract - Part 1
Anatomy of the nasal cavities
The anterior openings (the nares) are formed by the two nostrils.
The posterior openings (called the choanae) open into the nasopharynx
The floor of the nasal cavity is formed by the maxillary bone and the palatine bone, which form the hard palate (ie, roof of the oral cavity)
The medial walls are formed by a midline nasal septum made of ethmoid and vomer bone(inferior to ethmoid) (posteriorly) and septal cartilage (anteriorly).
The lateral walls are formed by a number of the bones of the skull, by cartilage and soft tissues.
Three nasal conchae (curled shelves of bone – also called the ‘turbinates’) protrude from lateral walls – superior, middle and inferior.
The conchae create 4 air channels/meatuses, which are contained within the respiratory regions of the nasal cavity.
What is the function of the Conchae/Turbinates?
increase the surface area of contact between tissues of the lateral wall of the nasal cavity and the respired air.
This improves the filtration, heating and humidification of inspired air
What covers the nasal cavity?
thick, vascular, glandular mucosal layer with pseudostratified ciliated columnar respiratory epithelium. This contains erectile tissue with venous sinusoids which will intermittently fill with blood.
What are the paranasal sinuses?
Frontal, Ethmoidal, Maxillary, Sphenoidal
What are the function of the sinuses?
Lighten the weight of the head, humidify and heat inhaled air, increase the resonance of speech.
What can cause the spread of disease from sinuses?
The close anatomical relations of the sinuses to the orbit, the meninges (linings of the brain) and the brain and the thin bony walls do make this possible.
What epithelium lines the sinuses?
Ciliated, mucous secreting respiratory epithelium
How are Pituitary adenomas removed?
Most pituitary tumours can be removed trans-sphenoidally.
The approach is through the sphenoid sinus.
What blood supplies the nasal cavities and the air sinuses
The arterial blood supply to the nasal cavities and paranasal sinuses come from branches of the facial, maxillary and ophthalmic arteries (from the internal and external carotid arteries)
What blood supplies the ethmoidal and frontal sinuses
Branches from the ophthalmic artery (a branch of the ICA) – also supply the ethmoidal and frontal sinuses
What blood supply supplies the lip and anterior nasal cavity?
Branches from the facial artery (a branch of the ECA) – supply lip and anterior nasal cavity
What blood supply supplies the nasal mucosa and also supplies the maxillary and sphenoidal sinuses?
Branches from the maxillary artery (a branch of the ECA) – form the main supply to nasal mucosa and also supplies the maxillary and sphenoidal sinuses
Where is a common site of nose bleeds?
An anastomotic plexus of arteries, lies on the anterior cartilaginous septum – this is a common site for nosebleeds (epistaxis)
Sensory nerve supply to the paranasal air sinuses?
The trigeminal nerve (CN V) is the major general sensory cranial nerve of the head and it has 3 major divisions.
The ophthalmic division provides the sensory supply to the upper part of the face, the maxillary division the middle part and the mandibular division to the lower part of the face.
The frontal sinuses are, therefore, supplied by the ophthalmic (V1) division
The ethmoidal and sphenoidal sinuses and nasal cavity are supplied by both the ophthalmic (V1) and maxillary (V2) divisions
The maxillary sinuses are supplied solely by the maxillary (V2) division
Nerve supply to the nasal cavities
Olfactory nerve (CN I) which is responsible for olfaction (our sense of smell)
The mucous producing cells of the nasal mucosa are supplied by parasympathetic neurons and the smooth muscle walls of blood vessel in the respiratory epithelium are supplied by sympathetic neurons which are both carried in the maxillary (CN V2) division of the trigeminal nerves (CN V).
General sensation - touch, pain and temperature from the nasal mucosa is carried by branches of the ophthalmic (CN V1) and maxillary (CN V2) divisions of the trigeminal nerve (CN V).
Describe apertures in the nasal cavity
Blood vessels, nerves and drainage enter and exit the nasal cavity via apertures in the bones of the skull.
List the main apertures in the nasal cavity
Cribriform plate – fibres of the olfactory nerve (CN I) and the branches from the ophthalmic vessels pass through here
Sphenoid sinus drains into the sphenoethmoidal recess above the superior concha
Maxillary, ethmoidal and frontal sinuses mainly drain into the middle meatus
Maxillary, ethmoidal and frontal sinuses mainly drain into the middle meatus
Why might an infection persist in the maxillary sinus?
The sinuses also drain into the nasal cavity.
All will drain assisted by gravity (except for the maxillary sinuses – this makes these sinuses more prone to infections).
Infections result in swollen mucosa, blocked drainage holes and subsequent pressure (and pain) on the nearby structures.
Explain the patterns of pain referral from the paranasal air sinuses.
Irritation of sensory nerves by inflammatory mediators, pressure changes, and a blocked non-draining sinus may present with pain which is felt away from the site of the actual pathology.
What is Sinusitis?
Pain over the site of an infected sinus is common in sinusitis (inflammation of the lining of the nasal cavity and the sinuses).
The infection may be viral or bacterial.
Symptoms of sinusitis
Nasal blockage, congestion, obstruction—essential for diagnosis
Nasal discharge (anterior rhinorrhoea or post-nasal drip)—essential for diagnosis
Reduced sense of smell (hyposmia)
Describe two pain patterns of sinusitis - referred pain.
The headache may result from frontal sinusitis due to compression/irritation of branches from the ophthalmic (CN V1) division of the trigeminal nerve (CN V).
Toothache may occur with acute maxillary sinusitis due to compression/irritation of branches from the maxillary (CN V2) division of the trigeminal nerve (CN V).
What does the pharynx do?
Conducts air to the larynx, trachea, and lungs
In breathing, air may flow through either the nose or the mouth but it always flows through the pharynx
Directs food to the oesophagus
During swallowing, the pharynx changes from an airway to a food channel
What is the pharynx?
Thepharynxis a Musculo membranous tube - extends from the choanae (posterior openings of the nasal cavity) to the oesophagus, which starts at the cricoid cartilage (vertebral level C6)