Oesophageal Physiology and function Flashcards
What are the 3 phases of swallowing?
Oral- voluntary
Pharyngeal-involuntary
Oesophageal- involuntary
What are the two parts of the oral phase?
preparatory phase- mastication and lubrication by saliva
Transfer phase- bolus is moved into back of mouth when the tongue moves into contact with the hard palate.
What happens during the pharyngeal phase?
Occurs in less than 1s, the bolus must move from the pharynx through the UOS (so must open), with the upper and lower airways closing as well as the mouth.
How are the three openings closed in the pharyngeal phase?
- Tongue pushes on palate to close off oral cavity/oropharynx
- soft palate elevates to seal nasopharynx
- epiglottis swings down and vocal cords and arytenoids adduct, sealing trachea/larnyx
What muscles make up the UOS and how does it relax during swallowing?
The three muscles are the cricopharyngeus, inferior pharyngeal sphincter and cervical oesophagus.
It relaxes when the cricopharyngeus relaxes, the suprahyoid and thyrohyoid muscles conract and due to bolus distending the UOS.
What does the oesophageal phase consist of?
UOS relaxing
Primary peristalsis: initiated by swallowing and is a continuation of pharyngeal constriction.
Secondary peristalsis: caused by distension caused by the bolus.
How do the muscular layers of the oesophagus contract to perform peristalsis?
The IC layer contracts before the bolus of food and the OL layer contracts in front of the bolus, shortening the oesophagus.
What is the junction of the oesophagus and the stomach?
The squamocolumnar junction/ Z-line, just proximal to the LOS
What are some things about the LOS?
Normally contracted, will relax 1-2 seconds after swallowing, will relax physiologically when upright.
What are ways you can investigate the oesophagus?
Gastroscopy/endoscopy- for physical problems Barium swallow pH study (acid reflux) Manometry
What is gastroesophageal reflux diseases pathophysiology?
During the transient opening of the LOS, acid refluxes into the oesohagus, corroding the epithelium. A disease affecting oesophageal and stomach motility
Can be enhanced by hiatus hernia, a hypotensive LOS (due to caffeine/alcohol) or impaired peristalsis (inability to clear)
What are the symptoms of acid reflux?
Heartburn
Sour/bitter taste in mouth
reurgitation coming
What can GORD lead to? (typically a disease due to motility)
Reflux oesophagitis- oesophageal wall becomes damaged, causing ulceration, bleeding
Peptic stricture- fibrosis and scarring narrows the passage
Barrets oesophagus
Cancer
What is Barrets oesophagus?
Due to GORD, intestinal metaplasia of the cells occur, where the epithelium of the oesophagus chnages from straitified squamous to simple collumnar like that of the stomach.
typical in males, 50 plus with high BMI and smoker
Higher risk of oesophageal adenocarcinoma (dysplasia of cells)
What are two types of oesophageal cancer?
adC and SqCC
SqCC occurs due to alcohol diet and smoking and occurs higher up on the oesophagus
