Flashcards in Oesophageal Function Deck (56)
What happens if accurate swallowing isn't achieved?
Aspiration (wrong hole)
What are the 3 phases of swallowing? Their sensory components are?
1) Oral (voluntary/striated muscle)
2) Pharyngeal (involuntary/stirated muscle)
3) Oesophageal (involuntary/ striated and smooth)
region in brainstem that receives sensory input from receptors in back of mouth and upper pharynx.
Also innervates swallowing muscles via cranial nerves
What is swallowing controlled by? What does that mean for stroke sufferers?
Cortex and brainstem. People who have had strokes in these areas can develop swallowing disorders
What are the phases of Oral Phase?
Preparatory phase ( formation of bolus)
Transfer Phase (bolus propelled into the pharynx)
Describe Preparation phase (oral phase)
Saliva= Lubrication and dissolving
Mastication = breaks down solids into smaller size, shape and consistency suitable for transport. Teeth grind, and tongue and cheeks position this to happen.
Describe Transfer phase (oral phase)
tip of tongue comes into contact with the hard palate.
close off anterior oral cavity
Bolus pushed to back off mouth
The Pharyngeal Phase #2
What are the 3 passages required to be closed in the pharyngeal phase?
2) upper airway/nasopharynx
3) Lower airway (to protect trachea from aspiration)
what is the UOS
upper oesophageal sphincter.
Acts as a barrier between the pharynx and oesophagus and is usually closed.
A complex of muscles often in a state of tonic contraction, that relaxes intermittently
What does UOS prevent?
air distending the stomach
reflux of contents into pharynx and larynx during oesophageal peristalsis
What muscles do UOS consist of?
Inferior Pharyngeal constrictor
How is it that UOS opens how for how long?
-suprahyoid and thyrohoid muscles contract
-pressure of descending bolus distendeds UOS
Opens for 0.5 s
Oesophagus Function and structure?
from UOS to LOS
mucosa= stratified squamous epithelium
upper 1/3 striated (voluntary)
lower 2/3 smooth (involuntary)
UOS relaxes, bolus enters and is propelled down oesophagus via peristalsis
Primary: initiated by swallowing, cont of pharyngeal contraction wave but slower, 3-5cm/s
Secondary: initiated by distention, activated stretch receptors initiate local reflex response > peristalsis
How does oesophageal peristalsis occur
ANS (para/sympathetic) and the Enteric NS
What are the nerve plexus of the GI tract
myenteric plexus (between circular longitudinal muscles)
Why is ES interesting?can operate independent/autonomously
can operate independent/ autonomously. Can also communicate with PS and S
The oesophagus is mostly covered in...
the circular layer contracts...
above and relaxes below bolus
the longitudinal layer
shortens during peristalsis
what is the LOS
a specialised segment of smooth muscle that is tonically contracted, close to the squamocolumnar junction (20-35 mmHg)
What causes LOS to relax
Swallowing: 1-2s after swallow, lasts 5-10s, followed by hypercontraction
Physiologically: intermittently relaxes to release air from stomach, only happens in an upright position, mediated via vagus nerve
Investigation of the Oesophagus
Gastroscopy: flexible telescope
Barium Swallow: xray test, asses function/motility
pH Study: may have reflux but unsure. involves cathater above gastro-oesophageal junction to test pH
Manometry: Like pH to test pressure/propagation of wave.
Structural diseases of the oesophagus
Dysmotility diseases of the oesophagus
abnormal contraction of the oesophageal muscles
Functional diseases of the oesophagus
disorders of motility, sensation and brain-gut dysfunction.
Gastro-oesophageal reflux disease
gastric contents into oesophagus. Occurs during transient LOS relaxation without the protective columnar epithelium, acidic contents damage.
When does Transient LOS relaxation become pathological?
When too much gastric juice refluxes into the oesophagus causing symptoms/disease