Oesophageal function Flashcards
Three phases of swallowing
Oral (voluntary, striated muscle)
Pharyngeal (involuntary, striated)
Oesophageal (involuntary, striated and smooth muscle)
Swallowing control centres
Swallowing centre in brainstem
Cortex
Describe pathways of the swallowing centre
Receives sensory input from receptors in the posterior mouth and upper pharynx and innervates swallowing muscles through cranial nerves
Part one: Two phases of oral phase
Preparatory phase and transfer phase
Preparatory phase
Mastication, wetting food, forming bolus
Transfer phase
Bolus propelled into pharynx
Part two: Pharyngeal phase
- Less than 1 sec, involuntary.
- Upper and lower airways closed by soft palate and the larynx moves up and epiglottis closes over vocal cords. Also tongue closes off oral cavity.
- UES relaxes.
- Bolus exits
UES functions
In a state of tonic contraction
Stops air moving freely into stomach.
Prevents reflux of contents of stomach.
Three muscles making up UES and if they contract or relax during swallowing
Cricopharyngeas (relax) Inferior pharyngeal constrictor (contract) Cervical oesophagus (contract)
Oesophageal phase (two phase and what initiates them)
Primary peristalsis, initiated by swallowing
Secondary peristalsis, initiated by distention from the bolus
Nervous control of oesophageal peristalsis
Autonomic nerves
Enteric nerves
Lower oesophageal sphincter
Located at the junction to stomach.
Z line- squamocolumnar junction
Normally contracted
Relaxes 1-2 seconds after swallowing and stays relaxed for 5-10 seconds then hyper contraction.
Intermittent physiological opening when upright to let air out of stomach
Barium test
Xray test allows us to examine the oesophagus in motion as a person swallows, function and motility. Can’t take biopsies
Endoscopy
Useful for structural pathologies e.g. damage to the mucosa. Can take biopsies
24 pH study
? reflux. Thin catheter in the oesophagus for 24 hours sits just above LOS measures a drop in pH in distal oesophgus.
Manometry
Catheter in oesophagus between UES and LES contraction measured to determine if peristaltic wave is normal.
Structural disorders
Ulceration Diverticulum Bleeding Stricture Inflammation Stricture Masses
Dysmotility
Abnormal contraction of oesophageal muscles
Gastro oesophageal reflux disease
Occurs when gastric acid enters the oesophagus during physiological opening of the LES. Becomes pathological when pt symptomatic.
Eitiology- relaxed sphincter (foods caffiene, alcohol, fatty food). Hiatus hernia (LES loses support of diaphragm), disorderd peristalis.
Symptoms of GORD
Burning over chest
Regurgitation
Sour bitter taste in mouth
Symptoms worsen when lying down or after eating
Complications of GORD
Reflux oesophagitis
Peptic sticture
Barrets oesophagus
Cancer
Haemotemisis
Vomiting up blood
Barrets oesophagus population at risk
Males over 50 with high BMI, smokers, chronic GORD. Increased risk of adenocarcinoma.
Transition from Barrets to adenocarcinoma
Squamous oesophagus, chronic inflammation, barrets metaplasia, low grade dysplasia, high grade dysplasia, invasive adenocarcinoma
Two types of oesophageal cancer
Adenocarcinoma and squamous cell carcinoma.
Seeing less of adenocarcinoma as treatment for reflux improving. Squamous cell carcinoma a lifestyle cancer.
Ring/ web
Thin membrane formed around inner edge of oesophagus. Can obstruct passage of food. Associated with hiatus hernia.
Zenkers diverticulum
Pouch at back of pharynx. People with impaired swallowing. Pressure in pharynx excessive forming diverticulum in weakest part. Present with dysphagia.
Stricture
Causes: Peptic, caustic (swallowing poisons), post radiotherapy, surgery to oesophagus (enastamosis stricture), cancer.
Infections of oesophagus
Oesophageal candidiasis (immunosupressed) Herpes, CMV (cause ulcerations)
Drugs causing ulceration
Doxycyclin
Eosinophilic oesophagitis
Eosinophils infiltrate the oesophagus- allergy mediated
Motility disorder:
Present with dysphagia, liquids and solids (structural usually just solids).
Achalasia
Myenteric plexus nerves disfunction. Loss of peristalsis in distal oesophagus, failure of distal oesophageal sphincter to relax.
Diffuse oesophageal spasm
When peristalsis occurs in random order (spasm). Corkscrew oesophagus.
Nutcracker oesophagus
Normal wave but high amplitude
Scleroderma
Connective tissue disease causing fibrosis of skin and connective tissue. Oesophagus turns into a rubbery hose pipe! Severe reflux.
