Chapter 99: Nasal Planum, Nasal Cavity and Sinuses Flashcards
What muscles allow for movement of the external nose (innervated by the facial nerve)?
- Levator nasolabialis
- Orbicularis oris
- Levator labii maxillaries
- Frontalis
Extensive resection of the nasal planum and incisive bone could result in hemorrhage, name the vessels from which this could occur from?
Major palatine artery, Paired dorsal and lateral nasal arteries
What ligaments support the cartilages of the external nose?
- Dorsal nasal ligament
- Paired lateral nasal ligaments
List the air passages in the nose:
Dorsal, middle, ventral and common meatus
What are the three paranasal sinuses?
- Maxillary recess
- Sphenoid sinus
- Frontal sinus - connected to nasal fossa via nasofrontal opening, through which an ethmoidal turbinate extends
What are the bony walls of the rostral nasopharynx (choanae)?
- Hard palate ventrally
- Vomer bone dorsally
- Palatine bone laterally
What is the mechanism of transmission of scent?
- Odorants bind to receptor on cilia arising from olfactory cells
- G-protein coupled mechanism causes transmembrane Na-channel opening and influx of intracellular Na
- Creates an action potential in olfactory nerves
What parts of the brain react to scent?
- Olfactory bulb
- Caudate nucleus when scent is associated with a positive reward or the owner
What makes the nose moist?
How does this contribute to immunity?
- Paired lateral nasal glands
- Secretions contain immunoglobulin A
What is ventral rhinotomy relatively contraindicated in young animals?
Damage to the vomer bone can alter the growth of the muzzle in dogs and shorten the transverse length of palate in cats
What are two proposed functions of the paranasal sinuses?
Vocal resonance
Humidification of air
At rest, dogs and cats can breathe through the nose. What happens during this process?
Inhaled air is warmed and humidified by the mucosa and the mucosa is cooled.
At exercise or in hot weather, what changes in the nasal mucosa?
Vessels dilate for better heat exchange. If not enough, switch to panting for evaporative cooling.
