Swallowing Flashcards
What happens to food before the process of swallowing occurs?
Mastication and mixing of saliva for formation of bolus
What are the 3 phases of swallowing
Voluntary, Pharyngeal and Oesophageal
What is the voluntary phase of swallowing?
Tongue moves bolus to the back of the pharynx
What is the pharyngeal phase of swallowing?
Afferent information from pressure receptors in the palate and anterior pharynx reaches the swallowing centre in the brain stem.
Swallowing centre mediates a set of movements:
- inhibition of breathing
- raising of larynx
- closing of glottis
- opening of UOS
What is the musculature of the oesophagus
Muscle of the upper third of the oesophagus is voluntary striated muscle that is under somatic control.
Muscle of the lower 2/3rds is smooth muscle under the control of the parasympathetic nervous system
What happens in the oesophageal phase of swallowing?
Peristaltic wave propels bolus to the stomach in approximately 9 seconds which is coordinated by the extrinsic nerves from the swallowing centre of the brain, and the LOS opens
What is dysphagia? How may it arise?
Difficulty swallowing.
May arise due to a primary oesophageal disorder such as achalasia - motility problems of the smooth muscle that prevents peristalsis
May also arise due to a secondary consequence of another issue - obstruction/compression of oesophagus due to trauma
What is odynophagia?
Pain upon swallowing
What are the two categories of dysphagia? How would we investigate each?
- oesophageal dysphagia - dysphagia for solid - investigate with barium swallow or endoscopy
- oropharyngeal dysphagia - dysphagia for liquids - investigate with endoscopy for evaluation of swallowing - most commonly due to stroke
Anatomically, how is gastro-oesophageal reflux prevented?Why is it a problem?
- lower oesophageal sphincter - one way valve at junction with the stomach
- angle of His found at the junction with stomahc
- crus of diaphragm helps with the sphincteric action also
Problems - mucosa of oesophagus and stomach are different - acid and peptic enzymes that don’t agitate the stomach mucosa, do oesophageal mucosa due to the lack of defences
What is Barrett’s oesophagus?
With which type of cancer is it commonly associated?
Metaplastic change from non-keratinised stratified squamous epithelia to columnar epithelium and goblet cells as an attempt to better resist the harmful contents of the stomach. Occurs with persistent gastro-oesophageal reflux.
Adenocarcinoma - particulalrly lethal cancer
What is GORD?
Reflux of stomach’s contents into the oesophagus and pharynx causing cough, hoarseness and asthma due to damage caused by the acidic contents.
