Anatomy Of Salivation And Swallowing Flashcards
What are the functions of saliva?
Lubrication
Maintains oral hygiene
Early stages of digestion
Protection from infection (innnate immunity)
Taste
Pathologically transmitting infection
What type of glands are salivary glands?
Exocrine glands
What is an exocrine gland?
Gland secreting its secretions into ducts
What is contained in saliva?
K+ and Bicarbonate (typically alkaline)
Mucins
Amylase
Lingual Lipase
Immune proteins
What type of molecule is mucin and what is its role?
Glycoprotein
Helps with lubrication
What gland secretes amylase?
What’s its role?
Salivary gland
Breaks down starch into sugars
What are some immune proteins found in saliva?
IgA
Lysozymes
Lactoferrin
What is the function of lactoferrin in the saliva?
It sequesters iron preventing bacteria using it for growth (e.coli)
What is the function of lysozymes?
Antimicrobrial (innate immunity)
What is Xerostomia?
Dry mouth due to no saliva production
What are some complications that can occur as a result of Xerostomia?
Poor nutrition (less amylase)
Infections in mouth (gingivitis, oral thrush)
Tooth decay, gum disease (acidic conditions not neutralised by alkaline saliva)
Halitosis
Poor sense of taste
What are the 2 types of gum in the mouth?
Lingual surface of gum
Buccal surface of gum
What is the lingual surface of gum?
The surface of the gum in contact with the tongue (so on the inside)
What is the Buccal surface of gum?
Surface of gum in contact with the cheek (outside)
What are deciduous teeth?
The milk teeth in children that will fall out
What is the biggest salivary gland?
Parotid gland (meaning near the ear gland)
How does the parotid duct travel?
It penetrates the Buccinator muscle draining into the oral cavity around the 2nd upper molar tooth
Where are the sublingual salivary glands located?
Above the floor of the mouth
What 2 salivary glands ducts are found on the floor of the mouth?
Submandibular salivary glands duct (seen the gland in DR)
Sublingual salivary gland
How are salivary secretions regulated?
Autonomic nervous system (neural)
What part of the autonomic nervous system is the main DRIVER of salivary secretion?
Parasympathetic nervous system
How does the sympathetic nervous system affects salivary production?
How does it do this?
Reduces salivary production
Vasoconstriction of blood vessels supplying salivary glands
What is an example of a drug that can cause a dry mouth as a side effect?
Atropine
What viral infection can infect the parotid gland leading to its inflammation and can also cause meningitis, testicular swelling, ovarian swelling?
MUMPs
Why is an inflamed parotid gland very painful?
The surrounding capsule is very tight so isn’t much room for expansion
What is parotid sialography?
Imaging of the parotid salivary gland
What is parotid sialography useful to see?
If a stone (calculus) or tumour is blocking the salivary flow
What does the prefix sialo- mean?
Salivary gland
What is a bolus?
Food that’s been chewed in the mouth and is ready to be swallowed
How do the lungs sit in relation to the oesophagus?
Lungs sit anteriorly to the oesophagus
What are the 3 phases to swallowing?
Oral preparatory phase
Pharyngeal phase
Oesophageal phase
What is the pharynx?
Muscular tube connecting the mouth to the oesophagus
State whether each of the 3 phases of swallowing is voluntary or involuntary?
Oral prepatory phase = Voluntary
Pharyngeal phase = involuntary
Oesophageal phase = involuntary
What occurs in the oral preparatory phase of swallowing?
Bolus pushed to back of mouth
Once it touches the pharyngeal wall the pharyngeal phase begins (swallow reflex starts)
What occurs during the Pharyngeal phase of swallowing?
Soft palate lifts up sealing nasopharynx (stops bolus entering nasal cavity)
Pharyngeal constrictors push bolus downwards (peristaltic)
Larynx elevates, epiglottis closes sealing trachea
Vocal cords Adduction help protect the air way
Upper oesophageal sphincter opens allowing bolus down
What is the epiglottis?
Elastic cartilage flap that’s closes protecting the airway/trachea
What are the vocal cords?
2 flaps of mucosa that are open when talking
What occurs during the Oesophageal phase of swallowing?
Upper oesophageal sphincter closes
Peristaltic wave carries bolus down into oesophagus
What are the pharyngeal constrictors?
Muscles at the top of the oesophagus
What are the sensory receptors in the swallow and gag reflex?
Where are they located?
Mechnoreceptors
In pharynx at back of throat
What nerve transmits the sensory input fro the mechanoreceptors in the back of the pharynx in the swallow/gag reflex?
Glossopharyngeal nerve = Cranial nerve IX
What part of the brain does the Glossopharyngeal nerve (Cranial nerve IX) transmit impulse from mechanoreceptors in the swallow/gag reflex?
Medulla
Once the information has been processed by the medulla in the swallow/gag reflex, what motor neurone transmits the impulse?
Vagus nerve (Cranial nerve X)
What muscles does the Vagus nerve (Cranial Nerve X) transmit impulses to in the swallow/gag reflex?
What do these muscles do?
Pharyngeal constrictors
Pushes bolus down to oesophagus
What is the swallow/gag reflex pathway from sensory neurone all the way to the motor response?
Mechnoreceptors in pharynx -> Glossopharyngeal nerve (IX) -> medulla -> Vagus nerve (X) -> pharyngeal constrictors
What determines whether the gag reflex or swallow reflex will be triggered if they are the same pathway?
Context
Age of individual (children under 3months will gag all food up)
What is Dysphagia?
Difficulty swallowing
Why may you be concerned about a patients swallowing whos had a stroke?
Stroke causes muscle weakness so muscles of pharynx can be weakened leading to poor coordination
How May oesophageal tumours affect swallowing?
Dysphagia
Make it harder to swallow solid boli
How does the oesophagus run through the body?
Runs from neck, through thoracic cavity into abdomen
Runs through posterior mediastinum posteriorly to the heart
What imaging technique of the heart can be done thanks to the oesophagus running through the posterior mediastinum posteriorly to the Heart?
Transoesophageal echocardiogram
What are the 4 narrowings of the oesophagus from most superior to inferior?
Junction of oesophagus with pharynx
Where aortic arch crosses oesophagus
Where oesophagus compressed by left main bronchus
At oesophageal hiatus where the oesophagus penetrates the diaphragm
What are the 4 narrowings of the oesophagus from most superior to inferior?
Junction of oesophagus with pharynx
Where aortic arch crosses oesophagus
Where oesophagus compressed by left main bronchus
At oesophageal hiatus where the oesophagus penetrates the diaphragm
What condition does continual gastro-oesophageal reflux cause in the lower oesophagus?
Metaplastic changes called Barrett’s Oesophagus
What helps prevent Gastro-oesophageal reflux?
Lower oesophgeal sphincter in distal oesophagus
Narrowing where oesophagus crosses diaphragm
Intrabdominal oesophagus gets compressed when abdominal pressure rises
Mucosal rosette at cardia
Acute angle of entry of oesophagus creates a flap which closes when pressure in stomach increases
What are the Mucosal rosette at the cardia?
Puckered mucosae that increase SA helping maintain the closure of the lower oesophageal sphincter
