Upper respiratory tract AHS1 Flashcards
What supports the nostrils?
Alar cartilage (elastic)
What is the name of the splanchnic bone in the pigs nose?
Os rostrale
What is the line called that goes between the nostrils and what animals is it in?
Philtrum (not the septum)
Carnivores
What is the name of the plate on an cows nose?
Nasolabial plate
Joins to the lip
What is the name of the scrolls of bone in the nose?
Conchae
What is the name of the specialised conchae nearest to the brain? What do they do?
Ethmoconchae
Olfaction - smell
What is the name of the passages through the conchae?
Meatuses
What are the 4 meatuses?
Common
Dorsal
Middle
Ventral
Where is the common meatus found?
Nearest to the cartilaginous septum
Where does the dorsal meatus lead? What does it do?
Leads to the frontal sinus (except in horses)
Allows the fontal sinus to drain into the nasal cavity
Where does the middle meatus lead?
To the ethmoconchae
Where does the ventral meatus lead?
To the nasopharynx
What is important about the ventral meatus in horses?
Must pass the stomach tube through the ventral meatus or will come to a dead end
What are paranasal sinuses?
Air filled spaces in the skull bone (pneumatic)
Which are the two most important paranasal sinuses?
The frontal sinus and the maxillary sinus
What are the species differences in the paranasal sinuses?
Dogs - poorly developed
Horses - extensive
What is the main structure of the sinuses in the horse?
Large frontal sinus
Maxillary sinus is split into rostral and caudal parts
What does the frontal sinus drain through in a horse?
The naso-maxillary opening into the maxillary sinuses
What is bad about the maxillary sinuses?
Close proximity to teeth so susceptible to infection
Poor drainage
What is the pharynx divided into and what divides it?
Naso and oro pharynx and the soft palette
What does the hyoid apparatus do?
Supports the larynx and tongue from the skull
How can the bones of the hyoid apparatus be remembered?
The Sick Elephant Can Be Treated
What are the 6 parts of the hyoid apparatus?
Tympanohyoid Stylohyoid Epihyoid Ceratohyoid Basihyoid Thyrohyoid
Which part of the hyoid apparatus is cartilage?
Tympanohyoid
Where does the hyoid apparatus join to the skull?
The Tympanohyoid cartilage articulates with the mastoid process
What is different about the basihyoid bone?
The only unpaired one
The lingual process comes off it in large animals to help support the tongue
Where does the thyrohyoid bone articulate?
With the thyroid cartilage of the larynx
What are the 4 main pieces of cartilage that form the larynx?
Epiglottis
Thyroid cartilage
Arytenoid cartilage
Cricoid cartilage
What is the epiglottis made of?
Elastic cartilage
Where is the epiglottis found?
Most rostral part of the larynx
What is the function of the epiglottis?
It covers the entrance to the larynx when swallowing
What is different about the epiglottis in horses?
It is retrovelar - behind the soft palette
This is why horses are obligate nasal breathers (cant breathe through their mouth)
What is the structure of the thyroid cartilage?
Made up of two sheets called lamina that are fused ventrally to form a U shape
What does the thyroid apparatus articulate with?
Dorsocranially (front) - thyrohyoid bone
Dorsocaudally (back) - cricoid cartilage
What is the structure of the arytenoid cartilage?
2 paired parts which are an irregular shape with many processes
Where does the arytenoid cartilage articulate?
With the cricoid cartilage on the medial surface
Look perpendicular to the larynx
What is the arytenoid cartilages function?
To open and close the glottis (airway)
To attach to the vocal ligament
What is the shape of the cricoid cartilage?
Signet ring shaped - broader dorsally (at top) than it is ventrally
What does the cricoid cartilage articulate with?
Articulates with both the thyroid cartilage and the arytenoid cartilages
Articulates caudally with the trachea
What is the main intrinsic laryngeal muscle?
Dorsal cricoarytenoideus muscle
What does the dorsal cricoarytenoideus muscle attach to?
From the dorsal surface of the cricoid to the arytenoid cartilage
What is the function of the dorsal cricoarytenoideus muscle?
Abducts the vocal ligaments to enlarge the glottis by rotating the arytenoid cartilage
What are the laryngeal muscles innervated by?
The recurrent laryngeal nerve
What is laryngeal hemiplegia?
Where damage to the recurrent laryngeal nerve paralyses the dorsal cricoarytenoideus muscle which impedes air flow
What is the name of the muscle that bridges the gap in the cartilaginous rings in the trachea?
The trachealis muscle
In carnivores which side does the trachealis muscle attach?
On the outside
What is the guttural pouch?
Only in horses
It connects the middle ear to the nasopharynx
What is the guttural pouch susceptible to?
Mycotic (fungal) infections
Important because lots of important nerves and blood vessels pass through it
