Mouth and Oesophagus Flashcards
What type of muscle and fibre are Lips and cheeks made up of?
Skeletal muscle in elasto-fibro CT
What is the oral cavity lined by?
stratified squamous epithelium, slightly keritanised on gums tongue hard palate for protection
What is the tongue composed of?
Skeletal muscle, interspersed with glands and covered with mucous membranes
How is the tongue intrinsic and extrinsic?
Intrinsic - to change shape
Extrinsic - allow movement
What is the position of the oesophagus?
Posterior, passes down midline of thorax through diaphargm at oesophageal hiatus ‘gap’ to enter abdomnen.
Where does the oesophagus recieve innervation from?
vagus nerve , 10th cranial
Describe layers of the oesophagus?
Mucosa - nonkeritanised stratified squamous as transit passage
Submucos - mucous secreting glands
Muscularis - skeletal, transitional, smooth
Serosa - is fibrous CT instead
What happens to the mucosa of oesophagus longitudinal folds?
Flatten out when filled
What are the 2 oesophageal sphincters?
Hypopharyngeal sphincter of skeletal muscle (upper)
Lower gastro-oesophageal or cardiac sphincter - has high pressure
What is gustation?
Taste
How is taste detected?
detects chemicals in saliva solution by use of chemoreceptors - taste buds
What does taste have a strong relationship with?
Olfaction - smell
What are the 5 primary tastes?
Sour - acid h+ content Salt - metal ions, Na modifies saltiness Bitter - plant alkaloids such as caffeine Sweet - mono-di saccharides, sugars Umami - glutamate content meatiness
Can all taste buds detect all taste?
Yes, but sensitive to 1
What is the position of 5 tastes on the tongue?
Tip - sweet
Sides of tip - salty
Back - bitter
Sides - sour
How many taste buds on tongue and where?
10,000 taste buds on epithelium on papillae
What are the 4 papillae and where are they based?
Filiform - not involved
Fungiform - mushroom on dorsal surface
Foliate - leaf on tip and sides
Circumvallate - grooved anterior/posterior
What do taste buds contain?
40-100 basal stems cells and gustatory
How often are taste buds replaced?
7-10 days by division of basal stem cells
Where are microvilli?
are the receptor membrane, project through taste pore to surface in saliva
What neurones are around gustatory cells?
Dendrites of sensory nerves - for brain perception of taste
What happens to taste?
Substance in saliva
enters taste pore attached to membrane
depolarisation of taste cell
neurotransmitter release to stimulate sensory neurone
neural path to brain 7 9 10 cranial
Impulses to tractus soliatarius of medulla to thalamus to parietal cortex
What disorders of the taste are there?
Aguestia - loss of taste could be from medication causing neuronal damage
Alterations in taste perception drug induced
Genetic deficiences - phenlythiourea cant taste bitter
What are 3 major pairs of salivary glands?
Parotid, submandibular, sublingual and numerous glands through mucosa
What type of secretions do each gland do?
Parotid - serous, water, a-amylase
Submandibular - seriousm mucous, weak a-amylase and lysozyme
Sublingual - mucous, thick viscous
What is saliva composed of?
> 99% water
<1% solids, ions
50+ proteins such as a-amylase, mucins, lysosome, immunoglobulins
What is PH of saliva?
6.2-8
What are flow rates of saliva and how much produced daily?
0.05 sleep
0.5 - 7ml at rest
1/2 L daily
Why is saliva needed?
For lubrication, movement, chewing, swallowing, taste sensation
Thirst, speech, chemical balance for tooth enamel
What does saliva digest?
A-amylase hydrolyses a-14 glyogosidic link of starch
What does saliva protect from?
Bacteriostatic , mucins, iga
How does saliva help dissolve absorbale drug?
glyceryl trinitrate - escapes first pass metabolism
What are disorders of salivary glands?
Mumps = infection of parotid by myxovirus
Xerostomia - dry mouth, people on medication, autoimmune, diabetes, age atrophy
What can lack of saliva do?
Make swallowing difficult
lead to problems with halitosis, gum disease, mouth infections, digestion not impaired if sufficient a-amylase from pancreas
What is mastication?
Chewing
How are teeth adapted to function?
Incisors - chisel for cutting, nipping
Canines - tearing, piercing
Molars for grinding crushing
When chewing how is jaw and tongue controlled?
Touch and pressure receptors in oral cavity and stretch receptors in muscles
What is the process of chewing?
up and down - biting of incisors
Side to side - crushing by molars
= mixing food with saliva to lubricate to allow taste
What is the max force generated by muscles for chewing?
250N to 900 N
Why is occulusal contact of molars important?
Determining efficiency of chewing
What are jaw movements involved with?
voluntary, involve cerebral cortex and skeletal muscle
What is bite strength controlled by?
sensory receptors in teeth signals to brain stem to stop/reduce
What does the tongue move with?
Lower jaw, shape alters to collect food in tongue until food ground, tongue moves bolus to swallowing
What is deglutition?
Swallowing
What kind of movement occurs with food processed?
voluntary to involuntary
What are 3 phases of swallwing?
Voluntary, pharyngeal, oesophageal
What happens in voluntary phase?
tongue seperates food into bolus and moves back and up to back of mouth
What happens in pharyngeal phase?
food into pharynx activate pressure receptor in palate and impulses in trigem and glossophar nerve to medulla cause elevation of soft palate, impulses from swallow centre inhibit respiration closes glottis, bolus tilts epiglottis back, sphincter opens by contraction, bolus passes and closes, glottis open breathing resumes
What happens in the oesophageal phase?
food moves down by peristalsis of circ SM by relaxationm progress by autonomic vagus nerve by swallow centre, as wave moves down, lower sphincter relaxes allow food to enter and close to prevent reflux
What increase the tone of sphincter and when?
Increased gastrin when stomach is filled
What is dysphagia?
Difficulty of swallowing
What are disroderds of deglutition?
Damage to cranial nerve or medulla swallow centre
degenerative disease of skeletal muscle -myasthenia gravis, polio dystrophy, defects in autonomic nerves e.g chagas diseases by trypan infection, achalsasia
Swallow reflex inactive, hiatus hernia, diffuse oesopha spasm, thick sm, GORD - reflux disease heartburn
