Pharynx, Oesophagus, Deglutition Flashcards
The pharynx is in the ____ region of the oral cavity and leads to the _____ systems
Caudal; respiratory and digestive
The pharynx has a transition from ____ to ____
Ectoderm (voluntary actions) to endoderm (involuntary actions)
Soft palate (3)
-continuous with hard palate
-moveable, muscular fold
-extends back from the caudal border of the hard palate
The soft palate divides the ____ into ____ spaces
Pharynx; 3
Three spaces of the pharynx
-nasopharynx (dorsal aspect)
-oropharynx (ventral aspect)
-laryngopharynx (caudal extension of BOTH naso- and oropharynx
The soft palate in dogs and cats (2)
-does NOT reach the epiglottis
-allows for both mouth and nose breathing
BOAS stands for ___ and is indicated by (2)
-brachycephalic obstructive airway syndrome
-elongation of the soft palate
-narrow nostrils/nares
A landmark for intubation is the
Palatoglossal arch
Soft tissue from the soft palate to the tongue at the isthmus is called the
Palatoglossal arch
The isthmus faucium is the
Entrance to the oropharynx
The free edge of the soft palate (tonsils) are called
Palatine velum
What connects the palate to the tongue
Palatoglossal arch
Soft tissue that extends caudally on either side of the soft palate
Palatopharyngeal arch
Three muscles of the soft palate
-tensor palati
-lavator palati
-palatinus
What muscle shortens the soft palate during contraction
Palatinus
What muscle tenses and straightens the soft palate
Tensor palati
Which muscle lifts the palate and closes the nasopharynx during swallowing
Levator palati
Nasopharynx (3)
-part of respiratory system
-dorsal to the soft palate
-opens into caudal nares (choanae) at junction of nasal cavity and into eustachian (auditory) tubes
The junction of the nasal cavity is where
The soft and hard palate meet
The nasopharynx is made of (2)
-pseudostratified ciliated epithelium that warms/humidifies the air
-scattered goblet cells that produce mucous and trap large particles
The oropharynx is made of
Stratified squamous epithelium
The laryngopharynx is made of
-stratified squamous epithelium
Nasopharyngeal polyps (4)
-found in cats
-originate in the ear or Eustachian tube
-grow in the nasopharynx
-eventually disrupt breathing
The Palatoglossal arches connect
The palate to the tongue via the isthmus fascium
Oropharynx (3)
-part of digestive system
-caudal to Palatoglossal arches
-when breathing through nose, ventral soft palate drops and comes in contact with the tongue to flatten the oropharynx
What separates the laryngopharynx and oropharynx
Annular fold
What part of the pharynx has no secretions and is used for protection only
Laryngopharynx
3 parts of the Laryngopharynx
-Ventral: pyriform recess on either side of larynx
-Dorsal: above the larynx
-Caudal: cricoid cartilage
Muscles of the pharynx (no names) (3)
-3 longitudinal muscles that receive food, dilate and shorten the pharynx
-3 circular muscles that constrict the pharynx and move bolt to epiglottis
-all are striated (skeletal) muscle covered in pharyngeal fascia
The swallowing reflex is
Involuntary
Lymphatic tissue of the pharynx (4)
-defends mucosal surface
-widespread in pharynx
-Mucosa associated lymphatic tissue (MALT)
-tonsils (follicular and non-follicular)
MALT stands for ___ and are ___
-mucosa associated lymphatic tissue
-lymphocytic infiltrations under the epithelium
Tonsils (5)
-lymph nodules
-interspereed with diffuse lymphatic tissue
-discrete organs
-non-follicular tonsils under a flat sheet of epithelium
-follicular tonsils increase surface area via invaginations
What non-follicular tonsils are found in the dog and cat
Palatine tonsils
What follicular tonsils are found in the ox
Sinus tonsillaris
5 types of tonsils
-pharyngeal
-tubal
-soft palate
-palatine
-lingual
Which type of tonsil is NOT present in carnivores
Tubal tonsil
Carnivore tonsils (3)
-lingual and soft palate tonsils diffuse
-pharyngeal tonsils are plate-like
-large palatine tonsils on lateral wall of oropharynx
Lingual tonsils are located at
The base of the tongue
The oropharynx is ___ to the nasopharynx
Ventral
Epiglottis (6)
-leaf-like elastic cartilage
-caudal to tongue
-flexible
-part of larynx
-a valve that closes the trachea
-most rostral of the laryngeal cartilages
What connects the pharynx to the stomach
Oesophagus
The nasopharynx is ___ to the oropharynx
Dorsal
Three parts of the oesophagus
- Cervical
- Thoracic
- Abdominal
The cervical oesophagus (3)
-starts at annular fold, dorsal to cricoid cartilage of larynx
-initially dorsal to trachea, then moves to the left
-extension of the laryngopharynx
Thoracic oesophagus (6)
-enters thorax on the left
-returns dorsal to trachea
-in dorsal mediastinum
-right of the aortic arch
-ventral to thoracic aorta
-runs between the lungs (oesophageal hiatus in diaphragm)
What is a congenital birth defect that causes regurgitation of solid food
Persistent right aortic arch
A dilation of the oesophagus causing loss of motility is called
Megaoesophagus
Four layers/tunics of the oesophagus (from in to out)
-Mucosa
-Submucosa
-Muscularis External
-Tunica Adventitia (cervical and thoracic) / Tunica Serosa (abdominal)
Abdominal oesophagus
short region leading to the cardia of stomach
The cardia of the stomach is where
The oesophagus enters the stomach via the Cardia Sphincter
In most animals, as the oesophagus goes toward the stomach, the diameter ____ and the muscle wall thickness ___
Decreases; increases
Mucosa layer of the oesophagus (4)
-stratified squamous epithelium
-distinct Cornified (keratin) layer
-lamina propria lacks glands
-muscularis mucosa is incomplete
Submucosa layer of the oesophagus (4)
-loose connective tissue
-contains mucous glands
-proximal only in cats (ie. near the pharynx)
-entire length in dogs
Muscularis externa layer of the oesophagus (5)
-initially spiral skeletal muscle
-remained is outer longitudinal and inner circular muscle
-forms cranial oesophageal spinster
-entire length is skeletal muscle in dogs
-proximal 2/3 is skeletal muscle in cats
Tunica Adventitia layer of the oesophagus (3)
-cervical and thoracic parts of oesophagus
-connective tissue sheath
-allows movement
Hyoid apparatus (3)
-U shaped arrangement of bones and cartilage
-provides a framework for pharynx and larynx
-controlled by complex set of muscles
The geniohyoid (4)
-major muscle of the hyoid apparatus
-within the inter-mandibular space
-pulls the larynx rostral and dorsal
-seals the larynx by the epiglottis
During deglutition, the ____ bone is pulled rostrally causing ___
Basihyoid; tip of epiglottis gets pushed between the laryngeal mouth and root of tongue (ie. covers the glottis)
The opening of the airways is the
Glottis
Deglutition (3)
-transfers food/drink from oral cavity to stomach
-initially voluntary movement (bonus forced into oropharynx by tongue)
-involuntary movements include swelling reflex, respiratory tract closing off, oesophagus dilating, and bolus being propelled into the oesophagus
Food bolus moves ___ by the action of ____
Caudally; the tongue (styloglossus and hyoglossus muscles)
The bolus moves down the oesophagus by a wave of ___ where ___ occurs
Constriction; peristalsis
Sphincters are always ___, except during swelling
Closed
Peristalsis (2)
-constriction caused by contractions of circular muscle BEHIND bolus
-contraction of longitudinal muscle AHEAD of bolus shortens the oesophagus
In suckling and drinking, the ___ is the major organ which helps create ___
Tongue; negative pressure for sucking
Which structure is dorsal to the soft palate
Nasopharynx
Regurgitation is ___ while vomiting is ___
Passive; active
As the oesophagus moves further down the neck, it travels to the
Left
Which layer of the oesophagus has no glands
Lamina propria
Geniohyoid muscle (2)
-major muscle of importance in deglutition
-moves hyoid and base of tongue rostrally and dorsally
Which structure covers the glottis during swallowing
Epiglottis
For vomiting to occur,
The pressure in the thoracic cavity must decrease
A decrease in the thoracic cavity pressure will cause
Ingesta to enter the oesophagus
____ and ___ brings ingesta back into the mouth during vomiting
Reverse peristalsis; abdominal muscle contraction
