tongue, pharynx, oesophagus, stomach Flashcards
(38 cards)
what 6 things occur ingroups of 3
3 extrinsic tongue muscles 3 sets of intrinsic tongue muscles 3 nerves supply the tongue 3 regions of the pharynx 3 circular muscles of the pharynx 3 longitudinal muscles of the pharynx
what can be seen in the midline and below the central incisors and what do they do
- 2 spikes of bone = superior genial spines
- attach largest muscles of the tongue (right and left genioglossus muscles)
- there are 4 but lower ones are covered by the above muscle
- the hyoid bone can also be seen (U shaped, free-floating) which provides attachment for many muscles ie the hyoglossus of tongue
what two sets of muscles does the tongue contain
3 sets of:
extrinsic (originate outside the tongue, act to move it around)
intrinsic (confined entirely to the tongue, act to change its shape)
why are the extrinsic muscle names easy to remember
ALL combine the origin of the muscle
with “glossus” (from greek for tongue)
list the 3 extrinsic muscle of the tongue
1) STYLOGLOSSUS
2) HYOGLOSSUS
3) GENIOGLOSSUS
where does the styloglossus originate and what does it do
styloid process of temporal bone
lifts tongue up and back (as styloid process of temporal bone is fixed below external ear canal)
where does the hyloglossus originate and what does it do
hyoid bone
pulls tongue down (hyoid bone is mobile but muscles attaching to its inferior surface hold it in place so it cant be pulled upwards)
where does the genioglossus originate and what does it do
superior genial tubercles of mandible
protrudes the tongue (bc its attached anteriorly so pushes the tongue forwards when the Genioglossus contracts it)
what do intrinsic muscles occur as
sets of muscle fibres which intertwine together (cannot be dissected apart)
what are the 3 intrinsic muscle fibres
- horizontal
- vertical
- longitudinal
where are horizontal fibres and what do they do
stick out from coronal section/ midline in both directions
make tongue
1) narrower
2) longer
3) thicker vertically / thinner laterally
as they pull the sides of the tongue inwards when contract
why does the tongue get thicker in a vertical direction when it becomes narrower
certain volume of fluid in tongue
has to be accomodated for
where are vertical fibres and what do they do
mixed together with horizontal fibres in the core of the tongue make tongue 1) vertically thinner 2) thicker laterally 3) longer by drawing its dorsal surface down
where are longitudinal fibres and what do they do
2 sub groups (superior + inferior) run along length of tongue as they run along length they get shorter and ... Curve tip of tongue up (superior group) or down (inferior group)
which nerve supplies motor supply to all muscles of the tongue
cranial nerve XII
= hypoglossal nerve (true hypoglossal nerve fibres arise in hypoglossal nucleus in the brain and are ALL motor fibres. ALL they do is supply the muscles of the tongue)
although other muscles are not directly supplied by the hypoglossal nerve, how are they involved
fibres supplying most of them travel in the hypoglossal nerve at some point
BUT arise from spinal nerves NOT hypoglossal nerves
so hypoglossal nerve transmits other nerve fibres that have arisen elsewhere
what is the pharynx and where does it run
tube-like structure but not a complete tube (anterior aspect is open to region in front)
posterior to nasal and oral cavities and the larynx
why is the pharynx open anteriorly
- air from nasal cavity can get into nasopharynx
air food water from oral cavity = into oropharynx
(then on into larynx, trachea then lungs or GI tract)
what are the 3 defined regions of the pharynx and where do they lie
- NASOPHARYNX (posterior to the nasal cavity)
- OROPHARYNX (posterior to the oral cavity)
- LARYNGOPHARYNX
(posterior to the larynx)
the wall of the pharynx is muscular, what does it consist of
3 outer circular muscles (on each side of head) which form outer muscle layer (muscles lay on outside) and run around the pharynx
1) superior constrictors
2) middle constrictors
3) inferior constrictors
which muscles form the inner muscular coat of the pharynx (muscles laying inside)
3 longitudinal muscles (on each side of head)
1) salpingopharyngeus
2) stylopharyngeus
3) palatopharyngeus
they run along + are found along length of pharynx
the circular layer lies outside the longitudinal layer
what nerve supplies motor supply to all but one of the outer and inner pharynx muscles
cranial nerve X
= vagus nerve
one is supplied by glossopharyngeal nerve
where does the pharynx join the oesophagus
same level larynx joins the trachea
what is present just above the junction where the pharynx joins the oesophagus and what is the issue with this
- weak area in pharyngeal wall
- allows mucosal lining of pharynx to bulge out forming ZENKERS DIVERTICULUM (a sac /out-pocketting of the pharynx)
- food can get trapped in it causing halitosis when it decays. it can also be regurgitated then swallowed
