Nasal cavity Flashcards
What are the 3 main functions of the nasal cavity?
- Warm and humidify air going to lungs
- Filter particles from air going to lungs.
- Detecting odour molecules in air
What two things take up the majority of space in the nasal cavity?
- Turbinate bones
2. Space between them = meatii
What is the main function of turbinate bones?
Increase the surface area of the nasal cavity
What are the 3 main groups of turbinate bones?
- Ethmoturbinates
- Dorsal turbinates
- Ventral turbinates
Which two cavities does the hard palate seperate?
Nasal and oral
What separates the nasal cavity and the brain?
Cribriform plate
Describe how the cross section through the back of the nasal cavity would look
Lots of ethmoturbinates
Pouches of the frontal sinus
Which process of the frontal sinus/bone develops into a horn?
Cornual process
Which turbinate shows the most species variation?
Ventral turbinate
How does the dogs ventral turbinate change rostrally to caudally?
Rostrally - meatii are visible
middle - millions of leaflets so very congested
caudal - less congested but still many leaflets
What type of epithelium lines:
a) midline septum
b) turbinates
a = respiratory epithelium b = olfactory epithelium
Describe the ventral turbinate in a horse
Only one scroll of bone as bottom scroll is lost
What are paranasal sinuses?
Air filled expansions of the nasal cavity between the inner and outer tables of bone
Why are paranasal sinuses prone to blockage by inflammation or congestion?
They retain connection with the nasal cavity via narrow openings
What are the 3 possible functions of paranasal sinuses?
- Mechanical protection
- Thermal protection
- Enlarge skull without adding weight
What breeds of dog have very small/lose their frontal sinus?
Brachycephalic breeds
What is the main nerve that pertains to the horn?
Cornual nerve - from trigeminal nerve
When undertaking euthanasia by shooting where should be aimed for to be most humane, what should be avoided?
- aim for medulla oblongata (the respiratory and cardiovascular centre of the brain)
- avoid midline on species with a strong bony midline septum
How is drainage of the frontal sinus different in horses compared to other species?
- Other species drains into the back of the nasal cavity
- Horses drains into the maxillary sinus
Which duct connects the corner of the eye to the end of the nose?
Nasolacrimal duct
What subdivides the ventral part of the maxillary sinus?
Bony plate that supports the infraorbital canal
Why, in a young horse, are the lateral parts of the maxillary sinus much smaller?
Due to the unerupted cheek teeth occupying the maxillary space
The hard palate is made up from which bones?
The palatine, maxilla and incisive bones
