Anatomy- Upper GI Tract Flashcards
what are the components of the GI tract in each part of the body
head (oral cavity, pharnyx)
neck (pharynx, oesophagus)
chest (oesophagus)
abdomen (stomach, small intestine, large intestine)
pelvis (rectum, anal canal)
perineum (anus)
what is the function of the upper GI tract
mastication (chewing)
degulutition (swallowing)
taste
salivation
what does mastication facilitate
taste and digestion by mixing food with saliva and increases the surface area of the food
what is the role of the buccinator muscle
pushes food into middle of mouth for mastication- also muscle of facial expression
how many teeth do adults have
32, 16 top and bottom
what are the four quadrants of the mouth
upper right, upper left, lower right, lower left
what is another name for the upper dental arch
maxiillary
what is another name for the lower dental arch
mandibular
what is significant about the second maxillary molar
the parotid gland passes over the masseter muscle to insert and drain into the cheek at the level of the second maxillary molar
how care the teeth numbered
1-8 in each quadrant starting in middle
1&2 incisor
3 canine
4&5 premolars
6,7&8 molar (8 wisdom)
at what age should all teeth be erupted
18
what bones and joints are involved in chewing
temporal bone and mandible
temporomandibular joint
what happens in the head of the condylar process goes pas the articular tubicle
jaw dislocation
What are the four muscles of mastication innervated by
mandibular division of the trigeminal nerve (CN V3)
what are the four muscle of mastication
temporalis m, masseter m, lateral pterygoid, medial pterygoid
which muscles of mastication close/ open the jaw
3 close
-temporalis, masseter, medial pterygoid
1 open
lateral pterygoid
where does the temporalis attach
coronoid process of mandible to temporal fossa
where does the masseter attach
angle of mandible to zygomatic arch
which muscle of mastication is the strongest
messeter
where does the lateral pterygoid attach
condyle of mandible to pterygoid plates of sphenoid bone
where does the medial pterygoid attach
angle of mandible (medial side) to pterygoid plates of sphenoid bone (mimics masseter on the inside)
what separates the two cavities in the temporomandibular joints
an articular disc
what are the two cavities in the TMJ and what are their purposes
superior cavity for translation
inferior cavity for rotation
what allows for more rotation of the jaw
pulling it forward onto the articular tubercle of the temporal bone
does the CN V3 have sensory or motor fibres
both
what is the course of the mandibular division of the trigeminal nerve
leaves pons, through foramen ovale, to muscle of mastication and sensory area
what is the only bone in the body not connected to another bone
hyoid
what risk do loose teeth pose
choking hazard
what is gingival mucosa
that portion of the oral mucous membrane that covers and is attached to the necks of the teeth and the alveolar process of the jaws
how is the tongue divided
posterior 1/3rd and anterior 2/3rds separated by the sulcus terminalus line
describe the posterior 1/3rd of the tongue and its location and function
vertical part, in oropharynx, taste and general sensation
what nerve innervates the posterior part of the tongue
CNIX
describe the anterior 2/3rds of the tongue and its location and function
horizontal part, in oral cavity, taste and general sensory
what projections on the tongue have taste buds
foliate papillae, vallate papillae and fungiform papillae (singular papillae)
what part of tongue at tip sense for tough, temp etc
filiform papillae
what is the role of the facial nerve
special sensory, sensory, motor and parasympathetic
what is the course of the facial nerve
from pontomedullary junction, through temporal bone via internal accoustic meatus then stylomastoid foramen, to supply taste ant. 2/3rds of tongue, muscles of facial expression, glands in the floor of the mouth
what is in the superior half of the oral cavity and what innervates it
gingiva and palate- general sensation CN V2
what is in the inferior half of the oral cavity and what innervates it
gingiva and floor of mouth- generl sensation CNV3
what is the gag relfex
protective reflex that prevents foreign bodies from entering the pharynx or larynx
what carries the sensory part of the gag reflex
nerve fibres within the CN IX
what carries the motor part of the gag reflex
nerve fibres within the VN IX
what nerves will a local anaesthetic block in an endoscope
will block action potentials in CN V2, CN v3, CN VII, CN IX
why is the gag reflex not there when a patient is unconscious
as a conscious reflex
what is the CN V2
maxillary division of the trigeminal nerve - sensory fibres
what is the course of the CN V2
from pons through foramen rotundum, to sensory area- mid face (through eyelid down to nose)
what is the CN IX
glossopharyngeal nerve
what is the role of the glossopharyngeal nerve
special sensory, sensory, motor, visceral afferent and parasympathetic
what is the course of the glossopharyngeal nerve
from medula, through jugular foramen, to posterior wall of oropharynx (sensory), parotid gland (secretomotor) and post. 1/3rd tongue (sensation and taste)
what order are cranial nerves in
anterior to posterior
what are the three salivary glands
parotid gland, submandibular, sublingual
where is the submandibular
enters floor of mouth and secretes via lingual caruncle
where is the sublingual gland
lays in floor of mouth secretes via several ducts superiorly
what number tooth is the upper 2nd molar
upper 7th
how is the tongue held in the mouth
suspended in oral cavity by 4 pairs of skeletal muscle
what is the role of the extrinsic muscles of the tongue
function to change the position of the tongue during mastication, swallowing and speech
how many intrinsic muscles are in the tongue and what do they do
4 pairs, located dorsally and posteriorly
modify the shape of the tongue during function
what are the 4 muscle of the tongue
genioglossus, hyoglossus, styloglossus, palatoglossus
what are the tongue muscles innervated by
all by CNXII (hypoglossal nerve- just motor) EXCEPT palatoglossus
what movements do the tongue muscles allow
hyoglossus- down and back
hyoglossus, styloglossus and palatoglosus- back
genioglossus- forward
what is the role of the hypoglossal nerve
motor only
what is the course of the hypoglossal nerve
from medulla, through hypoglossal canal, to extrinsic and intrinsic muscle of tongue (EXCEPT PALATOGLOSSUS)
describe the constrictor muscles in the pharynx
circular muscles- 3 surround back of pharynx, contract sequentially to move bolus
are muscles in the pharynx voluntary or not
yes- can control them but not control sequence of swallowing
what and where is the Cricopharyngeus
junction between pharynx and oesophagus= upper oesophageal sphincter- C6
what is the midline raphe
where muscle insert into each other
what innervates the muscles in the pharynx
CNX
what other muscles are in the pharnyx
longitudinal
describe the process of swallowing
Close the lips to prevent drooling (orbicularis oris & cranial nerve VII)
The tongue (cranial nerve XII) pushes the bolus posteriorly towards the oropharynx
Sequentially contract the pharyngeal constrictor muscles (cranial nerve X) to
push the bolus inferiorly towards the oesophagus
At the same time the inner longitudinal layer of pharyngeal muscles (cranial
nerves IX & X) contracts to raise the larynx, shortening the pharynx and closing
off the laryngeal inlet to help prevent aspiration
The bolus reaches the oesophagus
what muscle in the pharynx is not innervated by the CN X and what innervates it instead
Stylopharyngeus
CN IX
what is an edoscopy used to do
vie the inside of the GI tract
what do all the muscles involved in swallowing have in common and what does this mean
all skeletal - initiation is voluntary
all supplied by cranial nerves
how do parasympathetics affect peristalsis
Parasympathetics (speed up peristalsis)
Sympathetics (slow down peristalsis)
describe the enteric nervous system
Extensive network of nerves, found only in walls of GI tract
- Acts independently of other parts of nervous system, but can also be influenced by autonomic motor nerves
what is the oesophagus
inferior continuation of the laryngopharynx
where does the oesophagus begin
inferior edge or cricopharyngeus muscle (V6)
how do the walls of the oesophagus sit when there is no food present
together- as is a muscular tube
what two types of sphincter does the oesophagus have
anatomical upper and physiological lower
where is the oesophageal plexus and what does it carry and what is its role
runs on surface to supply smooth muscle within its walls
contains parasympathetic (vagal) and sympathetic nerve fibres
these influence the ENS and peristalsis
where does the oesophagus terminate
when it enters the cardia of the stomach
where is the oesophagus in relation to the trachea
posterior to it
how can left atrial dilatation cause dysphagia
as oesophagus in contact with posterior aspect of heart
what is a physiological sphincter
not true sphincter as when in goes through the diaphragm
what produces the sphincter effect in the lower oesophagus
contraction of the diaphragm,
intrabdominal pressure slightly higher than intragastric pressure,
oblique angle at which oesophagus enters the cardia of the stomach
what does the lower oesophageal sphincter help do
reduce occurrence of reflux
what will reduce the effectiveness of the lower oesophageal sphincter
presence of a hiatus hernia
where is the lower oesophageal sphincter
immediatley superior to gastro-oesophageal junction
where is the stomach when a patient is supine
Lies mainly in the left hypochodrium, epigastric and umbilical regions
what general shape in the stomach
J
where in stomach is gas and air seen on an X-rar
in the fundus
what are rugae
folds that allow expansion of the stomach
