What are the general functions of the respiratory system?
- Gaseous exchange
- Contributes to temperature and acid base regulation
What are the ancillary organs? What is their function?
- Passages to and from the lungs
- Air conditioning and volume regulation
The diaphragm forms the partition between which two body cavities?
The thoracic and abdominal cavities
What direction does the diaphragm move in during inspiration/expiration?
- Inspiration - caudally
- Expiration - cranially
What are the three types of skull conformations? Give an example of a breed for each
- Dolichocephalic - greyhound
- Mesaticephalic - labrador
- Brachycephalic - bulldog
Where does the nasal cavity extend to and from?
From the nares (nostrils) to the internal nares (conchae)
What structure divides the nasal cavity?
The nasal septum
What are the three regions of the nasal cavity?
- Nasal vestibule (most rostral) - nostrils and vestibule extend beyond skull
- Main cavity - dorsal, ventral nasal conchae
- Caudal region - ethmoidal conchae
What is the rostral/caudal limit of the nasal cavity?
- Rostral - nasal and incisive bones, nose and nasal vestibule extend beyond skull
- Caudal limit - cribiform plate of ethmoid bone
What supports the nose and nasal vestibule which extend beyond the skull?
Paired nasal cartilages
Which nerve supplies sensory innervation to the nose?
Infra-orbital nerve (branch of trigeminal nerve)
What divides the nostrils?
What shape are the nostrils in dogs?
A comma shaped wing
True or false: the skin of the nose is glandular in dogs?
False - it is a-glandular
Which glands moisten the nose?
The nasolacrimal and lateral nasal glands
Which artery supplies the nose?
Sphenopalatine artery (branch of maxillary artery)
What are the three mucosal folds present in the nasal vestibule?
Alar, dorsal and basal folds
Describe the difference in the conformation of the nasal septum between rostral and caudal
Rostrally the nasal septum will have a cartilaginous structure but as you move caudally it becomes bony
Which bone supports the nasal septum?
The vomer bone
What are the nasal conchae present in the dog?
Dorsal, middle, ventral and ethmoidal conchae
What is the function of the nasal conchae?
'Air conditioning' - they direct, slow, clean, warm and moisten air before it reaches the lungs
What are the spaces between bony structures through which air will pass known as?
What are the meatuses present in the dog?
Dorsal, middle, ventral and common meatuses
Where does the dorsal/middle/ventral meatuses lead to?
- Dorsal - olfactory epithelium
- Middle - paranasal sinuses
- Ventral - nasopharynx
Which meatus is used to pass a feeding tube down?
What is a paransal sinus?
Air filled spaces between plates of bone associated with the nasal cavity
What type of epithelium lines the paranasal sinuses?
Respiratory epithelium (psuedostratified ciliated columnar epithelium with goblet cells)
List the difference paranasal sinuses present in the dog. Which is of the most importance?
- Frontal, maxillary, palatine, sphenoidal, lacrimal
- Frontal is the most important
Which sinus is not a true sinus in carnivores?
The maxillary sinus (or recess).
Where is the maxillary recess located?
It is a wide opening above the 4th upper premolar
What are the functions of the paranasal sinuses?
- Lighten the head
- Protect the cranium
- Increase area for muscular attachment without an increase in weight
- Resonance function
What is the blood supply to the nose and nasal cavity?
- Nasal cavity - ethmoidal artery
- Satellite veins
What is the nerve supply to the nose and nasal cavity?
- Trigeminal nerve (sensory innervation to mucosa)
- Olfactory nerve (sensory innervation to olfactory mucosa)
What two structures are present in the nasopharynx?
Auditory tubes and pharyngeal tonsil
Where do the auditory tubes lead to?
The tympanic bulla
What type of epithelium lines the auditory tubes?
What is the function of the auditory tubes?
What is the blood supply to the common pharynx?
Asociated pharyngeal artery and cranial laryngeal artery
What is the motor/sensory nerve supply to the common pharynx?
- Sensory - trigeminal and glossopharyngeal nerves
- Motor - glossopharyngeal and vagus nerves
Where does the oesophagus lie in relation to the trachea in the common pharynx?
The oesophagus lies dorsal and caudal to the trachea
What are the rostral/caudal boundaries of the oropharynx?
- Rostral - last cheek tooth
- Caudal - epiglottis
What structure supports and moves the larynx? What direction does the larynx move in during swallowing?
- The hyoid apparatus
- It moves rostrally during swallowing