Swallowing and Vomiting Flashcards
What is the technical term for swallowing?
deglutition
How many phases are there in swallowing?
3
What are the phases of swallowing?
Oral, Pharyngeal and Esophageal
Which of the swallowing phases are voluntary?
oral phase
Which of the swallowing phases are involuntary?
pharyngeal and esophageal
How long does the entire swallowing process take on average?
6 seconds
Where is the soft palate positioned at the start of the oral phase of swallowing?
down and forward
What is the position of the food bolus in the start of the oral phase of swallowing?
pressed against the hard palate
Which cranial nerves are involved in the oral phase of swallowing?
Trigeminal, Facial, Hypoglossal
Where is the food bolus towards the end of the oral phase of swallowing?
pushed posteriorly towards the soft palate
What marks the end of the oral phase and the start of the pharyngeal phase of swallowing?
the elevation of the hyoid bone
What five things occur simultaneously in the pharyngeal phase?
elevation of the soft palate, contraction of palatine-pharyngeal folds, pulling together of the vocal cords, contraction of pharyngeal constrictor muscles, inhibition of the oesophageal sphincter by the vagal nerve
What is the purpose of the elevation of the soft palate in the pharyngeal phase of swallowing?
allows food bolus to move to the base of the tongue
What is the purpose of the contraction of the palatine-pharyngeal folds in the pharyngeal phase of swallowing?
pushes the food bolus down
What is the purpose of the pulling together of the vocal cords in the pharyngeal phase of swallowing?
prevents food entering the trachea and protects the airways
What is the purpose of the contraction of the pharyngeal constrictor muscles in the pharyngeal phase of swallowing?
pushes food to the esophagus
What is the purpose of the inhibition of the esophageal sphincter by the vagal nerve in the pharyngeal phase of swallowing?
prevents food entering the esophagus before it should
What are the suprahyoid muscles?
digastric, stylohyoid, mylohyoid, geniohyoid
Aside from the suprahyoid muscles, which muscles of the pharynx are involved with raising the hyoid bone?
palatopharyngeus and stylopharyngeus
Where is the epiglottis positioned in the oesophageal phase of swallowing?
down to close the airway
What is the purpose of the posterior cricoid cartilage in the oesophageal phase of swallowing?
it works with the posterior pharyngeal wall to create a pharyngeal oesophageal segment where the food bolus waits for the sphincter to open
What type of epithelium lines the oesophagus?
stratified epithelium
How long is the oesophagus?
20cm
What type of muscle forms the upper third of the oesophagus?
striated muscle fibres
What type of muscle forms the middle third of the oesophagus?
mixed striated and smooth muscle fibres
What type of muscle forms the lower third of the oesophagus?
smooth muscle fibres
Is the striated muscle of the oesophagus under voluntary or involuntary control?
involuntary
What marks the end of the oesophageal phase of swallowing?
the opening of the upper oesophageal sphincter
How does the upper oesophageal sphincter open?
contraction of the suprahyoid muscles causing lifting of the hyoid bone and larynx
Which cranial nerves supply innervation for the motor sections of swallowing?
glossopharyngeal, vagus, accessory
Which cranial nerves supply innervation for the sensory sections of swallowing?
hypoglossal, glossopharyngeal, vagus
Which brainstem nucleus is responsible for the motor portion of swallowing?
nucleus ambiguus
Which brainstem nucleus is responsible for the sensory portion of swallowing?
nucleus solitarius
How is swallowing controlled?
via a central pattern generator in the nucleus of the solitary tract and the reticular formation
Is swallowing or respiration dominant?
swallowing
When does swallowing occur in the masticatory cycle?
when the jaws are closed
Why does swallowing occur when the jaws are closed?
it stabilises the mandible and keeps the entrance to the pharynx stable
In infants, where is the epiglottis positioned compared to adults?
superiorly
What is the name for the collection of swallowing disorders?
dysphagia
What is the definition of dysphagia?
delay or disrupted passage of solids/ liquids from the oral cavity to stomach
Name four causes of dysphagia
muscle disorders, neuromusclar disorders, peripheral nerve disorders, CNS disorders
What is the technical word for vomiting?
Emesis
What is the definition of nausea?
a very unpleasant sensation that one may soon vomit
What is the definition of retching?
muscular activity of the abdomen and thorax, often voluntary, leading to forced inspiration against a closed mouth and glottis
What is dry heaving also known as?
retching
What is the definition of vomiting?
involuntary contractions of the abdominal, thoracic and GI muscles leading to forceful expulsion of stomach contents from the mouth
What is the definition of regurgitation?
effortless return of esophageal or gastric contents into the mouth unassociated with nausea
What is the definition of rumination?
food that is regurgitated in the postprandial period, re-chewed, and then re-swallowed
Is nausea always associated with vomiting?
no
Which sphincter is open during retching?
upper esophageal sphincter
What is the purpose to gagging?
to protect the airway
Is the gagging response the same for everyone?
no, it can vary from a small contraction of the soft palate to spasm in the pharynx
What is the purpose of vomiting?
rid the body of toxins
What controls the vomiting reflec?
a central pattern generator
What area of the brain is the chemoreceptor trigger zone?
area postrema
What are some gastrointestinal signals that can trigger vomiting?
activation of the 5-HT receptors, chemoreceptors of toxins, mechanoreceptors of distention
What are some central signals that can trigger vomiting?
area postrema activation
Why is the area postrema relevant?
it detects emetic signals from the blood and cerebrospinal fluid as well as receiving information from vagus and vestibular complex
What are some signals in the vestibular complex that can trigger vomiting?
motion stimuli can send signals to area postrema which can cause vomiting
What are some other general things that can trigger vomiting?
pregnancy, postoperative, alcohol excess, eating disorders
Is just one region in the brain responsible for the vomiting reflex?
no
What is the position of the soft palate and glottis in retching/vomiting?
soft palate is raised and the glottis is closed
Which cranial nerve controls the movement of the soft palate and glottis in retching and vomiting?
vagus
What is the efferent pathway of muscles involved in retching?
duodenum contraction, movement to stomach, stomach squeezed between abdominal muscles and diaphragm, relaxed lower esophageal sphincter
What is the efferent pathway of muscles involved in vomiting?
prolonged abdominal contraction, relaxed inner hiatal diagphram, relaxed oesophagus and lower oesophageal sphincter
What are some complications of prolonged and excessive vomiting?
weight loss, acid erosion of teeth, potential development of barretts oesophagus, inflamation of the oesophagus, mallory-weiss tears, electrolyte imbalance, metabolic alkalosis, renal issues
What receptors do emetics work on and how do they interact with them?
5-HT agonist, dopamine D2 agonist, opioids
What receptors do anti-emetics work on and how do they interact with them?
5-HT anatgonist, D2 antagonist
What imaging method can you use to investigate swallowing?
videofluorographic swallowing study