Upper respiratory tract Flashcards
What is the anatomy of the nasal cavities?
- Located between two bony orbits which contain eyes
- both have :
- Anterior/ posterior opening
- Floor/ roof - floor forned by maxillary bone and palatine bone, which form the hard palate
- Medianal and lateral walls
3 regions: - Nasal vestibules
- Olfactory regions
- Respiratory regions
- anterior openings (nares) formed by nostrils
- posterior openings - choanae- open into nasopharynx
What is the roof of the oral cavity made of ?
- frontal and nasal bones of the skull
- Cribriform plate contains small perforations for the olfactory nerves
What are the lateral walls of the nasal cavity formed of?
3 nasal conchae( shelves) of bone aka turbinates:
superior concha
middle concha
inferior conca
create 4 air channels/meatuses - contained within respiratory regions of the nasal cavity
What is the function of the conchae/ turbinates?
Conchae and meatuses = increase SA of contact between tissues of the lateral wall of the nasal cavity and the respired air
- Improves filtration, heating, humidification of inspired air
- Foreign material caught by nasal hairs in the vestibyle and mucus = usually swallowed
- pushes inspired air and odorants to the olfactory area due to turbulent airflow
Explain the histology of the conchae and nasal cavities
- Covered with thick, vascular, glandular mucosal layer with pseudostratified ciliated columnar resp epithelium
- Contains erectile tissue with venous sinusoids which will intermittently fill with blood
What are nasal polyps?
Caused by swelling and inflammation of the respiratory epithelium due to recurrent attacks of rhinitis .
What can deviated septums cause?
Sinus infections, snoring, difficulty breathing and sleep apnoea
What are paranasal air sinuses?
Air-filled spaces which lie within the bones of the skull of the same name
lined with ciliated, mucous secreting resp epithelium
Mucus from the sinuses drain into the nasal cavities via aperatrures within the lateral wall and roof
- close anatomical relations to the orbit (meninges lining of the brain, make the spread of infection possible
What is the blood supply of the nasal cavities and the air sinuses?
-Come from branches of the :
- facial: supply lip and anterior nasal cavity
- maxillary : Supply the nasal mucosa and supplies maxillary and sphenoidal sinuses
- opthalmic arteries : supply ethmodial and frontal sinuses
- internal and external carotid arteries
What is epistaxis?
- Nosebleeds caused by an anastomic plexus of arteries which lies on the anterior cartilaginous septum
What is the sensory nerve supply to the paranasal sinuses?
Trigmenal nerve:
Opthalmic division - provides sensory supply to the upper part of the face, maxillary divisom and mandibular division to the lower part of the face
1. Frontal sinuses supplied by the opthalmic V1 division
2. Ethmoidal and sphenoidal sinuses and nasal cavity are supplied by both the opthalmic and maxillary divisions
3. Maxillary sinuses are supplied solely by the maxillary V2 division
What is anosmia?
Loss of sense of smell and some loss of taste caused by an affect on the olfactory nerve cells ( fractures and COVID-19)
What are the mucous producing cells of the nasal mucosa supplied by?
- Parasympathetic neurons
What are the smooth muscle walls of blood vessels in the resp epithelium supplied by?
Sympathetic neurons which are both carried in the maxillary division of the trigeminal nerves
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What is the nerve supply for general sensation in the nasal cavities?
Touch, pain and temperature from the nasal mucosa is carried by branches of the opthalmic CNV1 and maxillary (CN V2) divisions if the trigeminal nerve