week 20 upper GI (mouth) Flashcards
how is the upper GI tract separated
sphincters
what is the natural pH of the stomach
2
what are the three parts that make up the small Intestine
duodenum
jejunum
ileum
what are the 4 funtions of the GI tract
motility
secretion
digestion
absorption
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how many functions are there in the GI tract
4
what does motility allow
movement of food mostly by action of smooth muscle
what does secretion allow
from the GI tract itself or from accessory organs as a result of stimuli (food, hormonal or neural)
what does digestion allow?
chemical breakdown of food by enzymatic digestion and mechanical breakdown of food
what does absorption allow
transfer of absorbable products of digestion into the blood or lymph to allow these simple chemical structures to facilitate cellular metabolism
how many layers are there in the basic epithelium in the GI tract
4
what are the 4 layers in the basic epithelium (innermost to outermost)
mucosa
submucosa
muscularis externa
serosa
what is the mucosa responsible for
protection
secretion
absorption
what is the submucosa responsible for
secretion
absorption
contains Meissner plexus in places
what is the muscularis externa responsible for
motility (peristalsis)
where is the serosa located
it is not present in all arts of the GI tract
what is the histogram structure of the mucosa
stratified squamous epithelium
within the histogram of the mucosa, what is the other structure that is present
muscularis mucosa and lamina propria
what layer forms a continuous sheet along the length of the GI tract
mucosa
what is the type of muscle cell exhibited on muscularis and lamina propria
smooth muscle cells connective tissue
in submucosa 2 separate muscle layers are separated by what
plexus (nerve cells)
in the muscularis externa - the inner and out layer are at what angle to eachother
perpendicular (90)
the submucosa contains the c_____
crypt
in the submucosa, what does the crypt do
contains cells that contain secretions for digestion and mucus and secretes products that are protective in some way
serosa has what kind of tissue
connective tissue and sometimes has squamous epithelium
what is the function of the serosa
anchors organs and tubes in place
provides general support to organs and tubes
what are the three routes of innervation from the autonomic nervous system
enteric NS
Sympathetic NS
Parasympathetic NS
what is the role of the Enteric Nervous system
plexi of neurons that innervate the GI tract to mediate muscle layers and provide sensory information about the state of the GI tract
what nerve controls the function of the sympathetic nervous system
splanchnic nerves
what nerve controls the function of the parasympathetic nervous system
vagus nerves (CN X)
what nerves control the function of the enteric nervous system
mesissner plexus
myenteric plexus
the meissner plexus is important for what
provides sensory info to relay to the brain
(if there are boluses or if there is contration)
the myenteric plexus is important for what
controlling function of muscularis externa
modulates function of the GI tract
first part of the GI tract is responsible for what
ingestion
mastication (chewing)
digestion
deglutition (swallowing)
the oral cavity contains glands important for what
sterilisation and digestion
what is the tongue responsible for
moves food during mastication
skeletal muscle fibres in 3 planes to allow finer control of motor movements
the tongue is covered in specialised ______ which induces what
mucosa
which induces salivary glands and taste buds
taste buds detect _ different tastes
5
salty and sour have what kind of activation
ion channel
sweet, bitter, and umami have what kind of activation
GPCR
what is the epithelial structure of the tongue
keratinised stratified squamous epithelium
what are salivary glands responsible for
serous fluid production
what is serous fluid responsible for
lubricates mouth, aids in initial digestion of carbohydrtaes and lipids
what are the three glands that secrete the majority of serous fluid
sublingual
submandibular
parotid
what does the sublingual secrete
mixed serous fluid and mucous solution
what does the submandibular secrete
mixed serous and mucous solution
what does the parotid secrete
serous fluid
what NS is in control of salivating at rest
parasympathetic
what are the proteins present from the salivary glands
lactoferrin
lysozyme
IgA
what are the enzymes present from the salivary glands
amylase
lipase
proteins secreted from salivary glands help protect what structure
teeth
lactoferrin has what properties
anitmicrobial
lysozyme has what properties
anti bacterial
IgA has what properties
anti viral and anti bacterial
what is the role od amylase
digests carbohydrates and breaks down sugar structures
what is the role of lipase
digests lipase and begins digestion
the three glands are innervated by what cranial nerves
VII and X
the swallowing reflex can be either _______– or _________________
voluntary or involuntrary
once mastication is complete the tongue moves food to where
oropharynx
what stimulates the swallowing complex
once the tongue has moved food to the oropharynx
how many stages are there in swallowing
3
what are the three phases in swallowing
oral preparatory phase
pharyngeal phase
oesophageal phase
what occurs in the preparatory phase (voluntary/involuntary)
pushes bolus towards pharynx
once bolus touches pharyngeal wall, pharyngeal phase begins
voluntary
what constitutes the end of the oral preparatory phase and the beginning of the pharyngeal phase
once the bolus touches the pharyngeal wall
what occurs in the pharyngeal phase (voluntary/involuntary)
soft palate seals of nasopharynx
pharyngeal constrictors push bolus downwards
larynx elevates, closing epiglottis
vocal cord adducts (protecting airway) and breathing temporarily
opening of the upper oesophageal sphincter
involuntary
what occurs in the oesophageal phase (voluntary/involuntary)
closure of the upper oesophageal sphincter
peristatic wave carries bolus downwards into oesophagus
incoluntary
