1b Upper GI Tract Flashcards
Where does the oesophagus run from in terms of vertabrae?
C5-T10
What type of muscle does each third of the oesophagus have?
Upper = Skeletal
Middle = Skeletal / Smooth
Lower = Smooth
Describe the change in epithelium which when going from the top of the oesophagus to the bottom?
Non keratinizing squamous epithelium to columnar epithelium
Which bone is the upper oesophageal sphincter related to?
Hyoid bone
What is the name of the ligament that attaches the diaphragm to the oesophagus?
Phrenoesophageal ligament
What is the function of this ligament? Phrenoesophageal ligament
Allows the independent movement of the diaphragm and oesophagus during respiration and swallowing
What is the angle of His?
Acute angle created between the cardia at the entrance to the stomach and the oesophagus
What is the function of the angle of His?
Prevents reflux of duodenal bile enzymes and gastric acid from entering the oesophagus
Which part of the diaphragm surrounds the LOS?
LEFT and RIGHT Crux
How much of the distal oesophagus is within the abdomen?
3-4 cm
What happens in stage 0 (Oral phase) of swallowing?
Chewing and saliva prepare the bolus
UOS and LOS are BOTH CLOSED
What happens in stage 1 (Pharyngeal phase) of swallowing?
Pharyngeal musculature guides food bolus towards the oesophagus
UOS opens reflexly
LOS Opened by the vasovagal reflex
Which reflex causes the LOS to open during the pharyngeal phase of swallowing?
receptive relaxation reflex
What happens in stage 2 (Upper oesophageal phase) of swallowing?
Upper sphincter closes
Superior circular muscle rings contract and inferior rings dilate
Sequential contractions of longitudinal muscle
What happens in stage 3 (lower oesophageal phase) of swallowing?
Lower sphincter closes as food passes through
As the bolus passes through the oesophagus, what happens to the muscles?
Superior muscles contract
Inferior muscles dilate in order to make space for the food bolus to pass through
What is manometry and what is it used to do?
When a probe is placed into the oesophagus and used to measure the pressure inside it
What is the pressure of normal peristaltic waves
About 40 mmHg
What is the LOS resting pressure?
About 20 mmHg
What happens to the pressure inside the oesophagus during receptive relaxation?
decreases to less than 5
What is the pressure and motility of the oeseophagus mediated by?
Inhibitory noncholinergic nonadrenergic neurones of myenteric plexus
What is the Receptive Relaxation of the LOS mediated by?
Inhibitory non-cholinergic noradrenergic (NCNA) neurons of myenteric plexus
They prevent constriction and so they induce relaxation
What is the most common reason for a functional disorder of the oesophagus?
Absence of a stricture
In the absence of the stricture, what is the most common cause of functional disorders of the oesophagus?
- Abnormal oesophageal contraction
- Failure of protective mechanisms for GORD
What is dysphagia?
Difficulty in swallowing
What is odynaphagia?
pain on swallowing
What is regurgitation?
Refers to the return of oesophageal contents from above an obstruction
What is meant by reflux?
The passive return of gastroduodenal contents to the mouth
What condition is caused by hypermobility?
Achalasia
What causes achalasia?
Due to loss of ganglion cells in Aurebach’s myenteric plexus in LOS wall, leading to DECREASED ACTIVITY inhibitory NCNA neurones - therefore more mobility
What is seen on images of the oesophagus in achalasia?
Birds beak = tapering of the distal oesophagus
Which conditions could cause oesophageal motor abnormalities similar to PRIMARY ACHALASIA?
Chagas’ disease
PROTOZOA INFECTION
Amyloid / Sarcoma / Eosinophillic Oesophagitis
Describe the onset of achalasia?
Insidious onset = symptoms for years prior to seeking help, without treatment can lead to progressive oesophageal dilation of oesophagus
What happens to the resting pressure of the LOS in achalasia?
Increased resting pressure
What happens to the receptive relaxation phase in achalasia?
Sets in too late, and is to weak
during the reflex phase the pressure in the LOS is markedly higher than stomach
How does achalasia cause dilation of the oesophagus?
Swallowed food collects in the oesophagus causing increased pressure throughout with dilation of the eosophagus
What is PD?
Pneumatic dilation
How is PD a treatment for achalasia?
Dilator into the LOS, inflated and causes the LOS to expand
PD weakens the LOS by circumferential stretching and tearing of the muscle fibres
LOS is too tight in Achalasia, therefore PD is needed to relax it to allow food to pass through the oesophagus
What happens to the LOS in achalasia?
TOO TIGHT
NCNA neurones cause the LOS to relax
Therefore if they are decreased activity in achalasia, the LOS becomes very tight
What is Heller’s myotomy?
A continuous myotomy performed for 6cm on the oesophagus and 3cm into the stomach
What is a dor fundoplication?
Anterior fundus folded over oesophagus and sutured to right side of myotomy
What is a dor fundoplication used to do?
Anti-reflux
What are the risks of surgery on the LOS?
Perforation
division of vagus nerve
splenic injury