reflux Flashcards
where does the oesophagus transport food from and to?
from pharynx to stomach
where does the oesophagus extend?
inferior border of cricoid cartilage to cardiac orifice of stomach (C6 to T11)
approx 25cm long
describe the anatomical course of the oesophagus.
- begins in neck (C6), continuous superiorly with laryngeal part of pharynx
- descends into superior mediastinum of thorax positioned between trachea and vertebral bodies of T1 to T4
- enters abdomen via oesophageal hiatus at T10 level (opening in diaphragm)
- abdominal portion of oesophagus approx 1.25cm, terminates by joining cardiac orifice of stomach at T11
what is the outermost layer of the oesophagus?
adventitia - outer layer of connective tissue
very distal and intraperitoneal part of oesophagus have serosa instead of adventitia
what is the second outermost layer of the oesophagus?
muscle layer
describe the structure of the muscle layer of the oesophagus.
external layer of longitudinal muscle
inner layer of circular muscle
describe the structure of the external layer of longitudinal muscle in the muscle layer of the oesophagus.
different muscle types in each third
- superior third - voluntary striated
- middle third - voluntary striated and smooth
- inferior third - smooth
what is the third outermost layer of the oesophagus?
submucosa
what is the fourth and innermost layer of the oesophagus?
mucosa - non keratinised stratified squamous epithelium (contiguous with columnar epithelium of stomach)
how is food transported through the oesophagus?
peristalsis - rhythmic contractions of muscles propagating down oesophagus
what interferes with peristalsis and what can this lead to?
hardening of muscular layers
can cause difficulty swallowing (dysphagia)
what is the function of the upper oesophageal sphincter?
acts to prevent entry of air
what is the function of the lower oesophageal sphincter?
acts to prevent reflux of gastric contents
what kind of sphincter is the upper oesophageal sphincter?
anatomical
striated muscle sphincter produced by the cricopharyngeus muscle
where is the upper oesophageal sphincter located?
junction between pharynx and oesophagus
how does the upper oesophagul sphincter carry out its function?
constricted to prevent air entering oesophagus
where is the lower oesophageal sphincter located?
gastro-oesophageal junction (between stomach and oesophagus, to the left of T11 vertebra)
how is the gastro oesophageal junction marked?
by change from oesophageal to gastric mucosa
what kind of sphincter is the lower oesophageal sphincter?
physiological - no specific sphincteric muscle, formed from four phenomena
what are the four phenomena that form the lower oesophageal sphincter?
- oesophagus enters stomach at an acute angle
- walls of intra-abdominal section of the oesophagus are compressed when there is a positive intra-abdominal pressure
- folds of mucosa present aid in occluding the lumen at the gastro-oesophageal junction
- right crus of the diaphragm has a “pinch-cock” effect
how does the lower oesophageal sphincter carry out its function?
during peristalsis the sphincter is relaxed to allow food to enter the stomach
at rest the sphincter prevents reflux of acidic gastric contents into the oesophagus
where are the four physiological constrictions in the lumen of the oesophagus? (ABCD)
Arch of aorta
Bronchus (left main stem)
Cricoid cartilage
Diaphragmatic hiatus
what are the anterior relations of the cervical and thoracic oesophagus?
- trachea
- left recurrent laryngeal nerve
- pericardium
what are the posterior relations of the cervical and thoracic oesophagus?
- thoracic vertebral bodies
- thoracic duct
- azygous veins
- descending aorta