238 Diseases Of Nose, Sinuses And Nasoparynx Flashcards
What are the three vital functions of the nose?
1) concha nasal is centralis for thermoregulation and conditioning of air
2) conchae ethmoidaes for olfaction
3) pulmonary alveoli for gas exchange.
What are the 4 functional segments of the nose?
1) nasal entrance
2) respiratory chamber
3) olfactory chamber
4) nasal exit
What is the nasal vestibule?
What does it do?
- voluminous bulb evolved from fusion o cranial termination of plica alaris(alar fold) with internal part of ala nasi (Nasi wing)
- Primarily responsible for distributing the in-and expired air and has highest airway resistance of the upper airways
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What does the nasolacrimal duct do?
= conducts lacrimal secretions from eye, -> not the vestibule by an orifice located rosto-medically into vestibular bulb.
What are the four air passages of the nasal cavity?
1) dorsal
2) middle
3) ventral
4) common nasal meats
What does the dorsal meatus do?
- bypass for odorant-bearing inspired air around the complicated structure of the ventral concha during sniffing for olfaction
2 types of conchae dominate the nasal cavity what are they? What are their functions?
1) ventral concha (attached to maxilla)
- function = thermoregulation and air conditioning
- complex airway network
2) ethmoidal conchae ( attached to cribiform plate of ethmoid)
- function = olfaction
- less complicated airway network.
How is the nasal exit formed?
What epithelia line the nasal passage?
- nasopharyngeal meatus, beginning with wing of vomer that crosses dorsal from medial to lateral and ends causally with choanae
- The outlet is a tine tubby which in small dogs is 1-3mm
- if both contralateral meatus are obstructed, the nasal respiration is impaired.
- epithelia lining the nasal passages = olfactory, respiratory, squamous, and transitional
What does mucus do in the nasal cavity? What cells produce it? What is the mucociliary apparatus?
Functions:
- homeostasis by providing defence against airborn irritants in nasal cavity and is essential for preventing foreign particles reach lungs.
- mucus is a watery sticky material linimum most luminal surfaces of the Nasal mucosa. It is a defence mechanism that filters the inhaled air by trapping particles and certain pours
- protein constitution contains bactericidal enzymes
- produced by goblet cells and subepithelial glands.
- mucociliary apparatus synchronises its beating of surface cilia to properly mucus at different speeds and indifferent directions. This helps drive the mucus along to the oropharynx where it is swallowed.
What epithelium lines the nasal chamber?
Vestibulum?
- vestibulum is lined by squamous epithelium (similar to skin)
- transitional epithelium covers transition into main nasal chamber
- non-olfactory nasal epithelium is ciliated epithelium
- ethmoidal conchae and caudal surface of septum are covered with olfactory epithelium.
- olfactory mucosa is covered with non-motile sensory cilia, enabling dog to detect odorant concentrations at 10,000-100,000 times that of a human.
How does a dog thermoregulate?
- inspired air flow through ventral nasal concha that has a large, rich vascularised surface of mucous membrane rolled into very fine space saving spiral lamella. The lateral nasal gland (glandular nasal is lateral is or Steno’s gland) located in maxillary recess provides moisture for evaporation.
What causes sneezing?
How does reverse sneezing occur? What does it achieve?
- mucosal irritant or discharge
- reverse sneezing = mechanosensitive aspiration reflex
- head may be extended and elbows abducted.
- Powerful contraction of inspiratory muscles and adduction of laryngeal cartilages generate negative pleural and tracheal pressure. The strong tracheal occlusion pressure with sudden opening of glottis while mouth is closed produces rapid inspiratory airflow though nose and nasopharyngeal. This tends to tear off irritant particles and accumulated mucus -> results in aspiration into oropharynx for swallowing.
Why is nasal discharge produced? What can cause nasal discharge?
- usually mucopurulent nasal discharge has serious underlying cause
- produced in nasal cavity as a reaction to mucosal inflammation and/or infection.
- Discharge can drain from paranasal sinuses,
Why is airflow obstruction considered serious?
What are some reported signs in pets by owners?
- Dogs complete inspiration through high anatomical nasal resistance (79% inspiratory, and 74% expiratory resistance)
- partial or bilateral obstruction will result in considerable loss of body weight.
- severe sleep problems result from permanent stenosis or intermittent collapse of airway.
- owners will report pets sleep in sitting position, and are regularly interuppted by waking up or gasping for air.
List the specific physical examinations of the nose?
- breathing sounds (strider)
- Symmetry of face and muzzle
- character of nasal discharge
- facial deformity or ulceration
- Patently of airflow through each nostril
- condition of teeth and gums
- examine roof of mouth of pharynx
- ability to retro pulse eyes
- pan on opening mouth or manipulating muzzle
- epiphora
- pigmentation/depigmentation of nose
- size and texture of submandibular lymph nodes
What can cause stenosis and obstruction of nasal passageways?
- hereditary malformations from excessive breeding can cause obstruction in nasal entrance, nasal cavity, and nasal exit
What can cause stenosis of nasal entrance? What is a challenge about treating it?
- trauma (bite, car accident, gunshot injury)
- chronic ulcerative inflammation(long-lasting sinonasal aspergillosis)
- surgery at nasal entrance using excessive thermal energy
- Surgery is challenging due to hi tendency for re-stenosing and temporal setting; a flp technique may be used to prevent this.
What causes stenosis of nasal cavity?
Intranasal obstruction is caused by any type of benign or malignant mass:
- tumours
- expanding granulation tissue induced by chronic inflammation
- intranasal cysts of varying origin.
- foreign bodies
- inspissated discharge
- deviated septum - high in small dog breeds and brachycephalic dogs. Also described in cats.
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What are oronasal and oronasopharyngeal communication?
What causes congenital deformities?
- Congenital or acquired communications between the oral cavity and the nose, respectively the oropharynx and the nasopharynx allows food and fluids to enter nasal pharyngeal passageways
- Secondary bacterial infection is common and sometimes fungal growth can be observed
- Congenital deformities are clefts of the lip and palate. The cause of clefting is unknown it is commonly agreed to be multifactorial with heriditary component.
- Acquired oronasal communications result from trauma of cardiac accidents or due to high-rise trauma; stick injuries; dental problems, malocclusion, and deformity of the normal nasal architecture and lips occur in rostral defects.
- long lasting processes such as chronic secondary bacterial inflammation cause expanding granulation tissue, and or inspissated discharge can obstruct nasal passageways.
