gastroenterology Flashcards
at what level does the oesophagus start and when does it end
start at C6
ends at t10 (where it enters diaphragm at oesophageal hiatus)
27cm length
how is the oesophagus divided and what muscle is present in each one
upper third - skeletal
middle third - skeletal and smooth
lower third - smooth
what is the mucosa of the upper third
non keratinising squamous epithelium
what is the mucosa of the lower third
columnar epithelium
what is between the pharynx and the upper oesophagus and what is it composed of
upper oesophageal sphincter
composed of thyropharyngeos and cricopharyngeos muscle
where are some normal places of constriction (if you swallowed something for eg)
- level of cricoid
- level of left main atrium/main bronchus
- t10 where it enters diaphragm
what is the angle at which the LOS enters the diaphragm
angle of His
what do the right and left crux of the diaphragm do
surrounds the LOS forming a muscular ring (mainly right)
what is the phrenooesophageal ligament
connective tissue covering oesophagus
how many cm are there of abdominal oesophagus
3-4cm
describe the stages of swallowing
stage 0 = oral phase
- chewing and saliva prepare bolus
- both UOS and LOS constricted
stage 1 = pharygneal phase
- pharyngeal musculature guides food bolus towards oesophagus
- UOS opens reflexly
- LOS opens by vasovagal reflex (receptive relaxation reflex)
stage 2 = upper oesophageal phase (autonomic)
- upper sphincter closes
- superior circular muscle rings contract and inferior rings dilate
- sequential contractions of longitudinal muscle
stage 3 = lower oesophageal phase (autonomic)
- lower sphincter closes as food passes through
important to note there is an initial relaxation phase then coordinated peristalsis
how do we determine oesophageal motility
normal range for peristalsis waves and LOS resting pressure
pressure measurements (manometry)
peristaltic waves - 40 mmHg
LOS resting pressure - 20 mmHg
decreases by <5 mmHg during receptive relaxation
mediated by inhibitory noncholinergic nonadrenergic (NCNA) neurons of myenteric plexus
what is the most common disorder of the oesophagus
reflux
how would you describe GORD
failure of protective mechanisms for reflux
what is dysphagia
difficulty in swallowing
- location important - cricopharyngeal sphincter or distal
type of dysphagia
- for solids or fluids
- intermittent or progressive (red flag symptom for oesophageal cancer)
what is odynophagia
pain on swallowing
what is regurgitation
return of oesophageal contents from above an obstruction
- can be functional or mechanical
what is reflux
passive return of gastroduodenal contents to the mouth
what is achalasia
failure of LOS to relax and some abnormality of peristalsis
loss of inhibitory ganglion cells in Aurebachs myenteric plexus in LOS wall
(decreased activity of inhibitory NCNA neurones)
increased resting pressure of LOS
peristaltic waves cease
- cause unknown
secondary causes - diseases causes oesophageal motor abnormalities similar to primary achalasia
- chagas disease (caused by parasite - secondary achalasia)
- protozoa infection
- amyloid/sarcoma/eosinophillic oesophagitis
what would you see in a barium swallow for achalasia
bird beak appearance
tapering of distal oesophagus and dilating oesophagus
late feature of achalasia :. not diagnostic
during the reflex phase how would you compare the pressure in the LOS to the stomach
during the reflex phase the pressure in LOS is markedly higher than in the stomach
what causes swallowed foods to collect in the oesophagus in achalasia
increased pressure throughout with dilation of the oesophagus
causing bacterial overgrowth and bad smells
what is the disease onset of achalasia
insidious onset
without treatment –> progressive oesophageal dilation of oesophagus
what is achalasia a risk factor for
squamous oesophageal cancer
