pharynx, esophagus and deglutition Flashcards
pharynx is common to both
respiration and digestive system
pharynx is
caudal region of oral cavity
within pharynx we see transition of structures derive from ____ to _____
ectoderm, endoderm
reflected in shift from voluntary to involuntary actions
what separates breathing and swallowing
epiglottis; valve like action
as well as movements of pharynx, larynx and hyoid apparatus
soft palate is
moveable muscular fold which extends back from caudal border of hard palate
soft palate divides pharynx into
an upper nasopharynx, a lower oropharynx and caudal extension of these 2; the laryngopharynx
how does soft palate differ in dogs/cats vs horses
- in dogs/cats soft palate does not reach epiglottis; breath through nose and mouth
- horses; soft palate reaches all way up to epiglottis; cannot breathe through mouth
the free edge (aka the palatine velum) of the soft palate which normally lies near the base of epiglottis may have a medial projection called the
uvula
brachycephalic dogs soft palate
- overlong soft palate; blocks airflow
- BOAS refers to overlong soft palate and narrow nostrils (some also gave narrow trachea on top of this)
palatopharyngeal arch
where the free edge of soft palate continues laterally as a surface fold which attaches soft palate to pharyngeal wall
(soft tissue extending caudally either side of soft palate)
palatoglossal arches
pair of folds that attach rostral end of soft palate to root of tongue
(soft tissue from soft palate to tongue at isthmus)
space between palatoglossal arches is the
isthmus faucium
entrance to oropharynx
what lies just caudal to palatoglossal arches, in the lateral wall of the oropharynx
the palatine tonsils
palatine velum
free edge of soft palate
3 major pairs of muscles in soft palate
- palatinus; shortens soft palate
- tensor palati; tenses and straightens soft palate
- levator palati; raise palate and close off nasopharynx during swallowing
what kind of epithelium does the nasopharynx have
pseudostratified, ciliated epithelium (= respiratory epithelium)
what does the nasopharynx open into
the caudal nares (choanae) and eustachian (auditory) tube
what can you see in cats that originate in the ear of eustachian tube but that develop a stalk and grow in the nasopharynx and eventually obstruct breathing
nasopharyngeal polyps
what kind of epithelium does oropharynx have
stratified squamous
when an animal is breathing through its nose what happens to oropharynx
the soft palate drops to contact the root of tongue and cavity of oropharynx dissapears
what kind of epithelium does the laryngopharynx have
stratified squamous
the laryngopharynx floor contains the
pyriform recess on either side of larynx
most of laryngopharynx lies ____ to the larynx and extends caudally as far as the ____
dorsal
cricoid cartilage
what separates the laryngopharynx from the esophagus
an annular fold
pharyngeal raphe
where lamina propria of laryngopharynx has numerous elastic fibers that condense to from a longitudinal elastic membrane in dorsal midline
several pharyngeal muscles insert on this raphe
describe the muscles in the pharynx
- 3 longitudinal muscles that dilate and shorten
- 3 circular muscles that constrict
- all striated skeletal muscles, operate mainly during swallowing reflex
what kind of tissue found in several places in pharynx is responsible for immune surveillance and defending breaches in mucosa
lymphatic tissue
describe forms of lymphatic tissue in the pharynx
- MALT: mucosa- associated lymphatic tissue; diffuse lymphocytic infiltrations
- tonsils; independent organs consisting of lymph nodules interspersed with with diffuse lymphatic tissue
tonsils can either be
follicular or non- follicular
follicular tonsils
increase SA by invaginations