Functions of the Mouth and Oesophagus Flashcards
What is the aim of mastication?
to increase SA for digestion
Where does carbohydrate and fat metabolism start?
in the mouth and oropharynx with salivary lipase and amylase
Whats the difference between endocrine and exocrine glands?
endocrine secrete directly into the blood whereas exocrine release into ducts which lead to their target tissues
What do the salivary glands secrete?
- mucous
- fluid
- IgA
- lysozymes
- lactoferrrin
What is the function of IgA, lysozyme and lactoferrin?
antibacterial
What do the acinar cells of the salivary glands produce?
enzymes
What do ductal cells of salivary glands produce and secrete?
- produce mucous in the goblets cells
- secrete water and electrolytes
What are the three types of salivary gland?
parotid
submandibular
sublingual
What are the roles of the secretions?
- lubricates
- hydrates (keeps oral mucosa moist, prevent dehydrations and cell death)
- cytoprotection (protects oral and oesophageal mucosa from damage)
- immune function
How does IgA work?
binds to pathogenic antigens
How does lactoferrin work?
binds iron and is a bactericidal
What is the role of lysozymes?
attack bacterial cell wall
How do the salivary secretions protect from pathogens?
- bind and neutralise toxins
- block viral attachment
- opsonise bacteria
- activate complement
- activate NK cells
- taken up by M cells in the bowel to simulate lymphoblasts and increase IgA secretion
What is the role of salivary duct cells?
- modify secretions of acinar cells
- extracts Na+ and Cl-
- secretes K+ and HCO3-
What are the features of saliva?
hypotonic and alkaline
Why is saliva alkaline?
- protect teeth from bacterial acid
- neuralises gastric acid reflux
Name two salivary gland diseases
Sjogren’s syndrome
mumps virus (parotitis)
(can learn about these on slides)
What source and ganglion parasympathetically innervates the submandibular and sublingual gland and what is the stimulation?
- 7th cranial nerve (facial)
- otic ganglion
- secretion
What source and ganglion parasympathetically innervates the parotid gland and what is the stimulation?
- 9th cranial nerve
- submandibular ganglion
- glossopharyngeal nerve
- secretion
What source and ganglion innervates the glands sympathetically and what is the effect?
- thoracic sympathetics
- vasoconstriction
- thick mucous secretion
What are the four phases of swallowing?
- oral preparatory phase (mastication)
- oral phase (tongue propels food posteriorly until pharyngeal swallow is triggered)
- pharyngeal phase (bolus transported through pharynx with co-ordinated closure of glottis, cessation of breathing and relaxation of oesophageal sphincter)
- oesophageal phase (peristalsis moves bolus to lower oesophageal sphincter)
What nerves cause swallowing?
- centre in medulla
- trigeminal nerve (V)
- glossopharanygeal nerve (IX)
- Vagus (X)
- hypoglossal (XII)
Swallowing diseases?
pseudo bulbar and bulbar palsies
Symptoms of swallowing diseases?
- difficulty swallowing
- altered speech
- loss of gag reflex
What maintains the lower oesophageal sphincter tone?
CCK, gastrin and vagal stimulation
What mechanisms prevent acid reflux?
- lower sphincter tone
- intra-abdominal length of oesophagus (protects oesophagus in changes in abdominal pressure)
- crural sling (diaphragm fibres close the GO junction)
- acute angle of His (accentuates sphincter and crural sling)
- mucosal rossette (low pressure seal)
Look at ways acid reflux can be caused
on slides
What is GORD?
chronic symptoms pr mucosal damage produced by abnormal reflux in the oesophagus
What are the causes of GORD?
- obesity
- hiatus hernia (stomach moving to wrong part of body)
- drugs that lower LOS tone
- pregnancy
- gastrin secreting tumour (Zollinger Ellison syndrome)
Symptoms of GORD?
- heartburn
- regurgitation
- dysphagia
- cough
- hoarseness
- chronic earache
What is dysphagia?
swallowing difficulties
What are the outcomes of GORD?
- oesophagitis
- stricture (narrowing)
- Barrett’s metaplasia
- Oesophageal adenocarcinoma
How is GORD diagnosed?
- 24 PH monitoring
- contrast swallow
Three types pf GORD treatment?
- conservative
- medical
- surgical
Describe medical?
- decrease acid by using proton pump inhibitors
- use antacids to increase PH
- alginates coat mucosa
Describe conservative treatment
- weight loss
- avoid food close to bed
- decrease alcohol
- raise head
Describe surgical
- ant-reflux surgery
- repair hiatus hernia
What is Barrett’s metaplasia?
change of epithelial cells in response to environmental stress
What can BM lead to?
oesophageal adenocarcinoma
What are the types of oesophageal cancer?
- squamous cell carcinoma
- adenocarinoma
What is the difference between the two types?
SCC is mid and upper whereas A is in lower, A is a premalignant lesion and SCC isn’t. A is only caused by reflux whereas SCC is caused by alcohol, tobacco, strictures etc…
What is achalasia?
-motor disorder of the oesophagus-loss of myenteric plexus at LOS (LOS doesn’t relax)
Symptoms of Achalasia?
- dysphagia
- regurgitation
- chest discomfort
- halitosis
How is achalasia treated?
- botox injection at LOS
- oesophageal dialtion
- surgery
