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DIGESTIVE > LECTURE 6 - oesophageal function > Flashcards

LECTURE 6 - oesophageal function Flashcards

1
Q

what muscle is in the upper 1/3 of the oesophagus, UOS, pharynx

A

striated muscle

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2
Q

what muscle is in the lower 2/3 of the oesophagus, LOS

A

smooth muscle

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3
Q

what state are sphincters at resting state

A

closed- and relax intermittently and open by normal physiological functioning

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4
Q

how fast is the pharyngeal swallow

A

<1sec

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5
Q

what controls the pharyngeal swallow

A

skeletal muscle contraction is coordinated by the swallowing centre in the medulla

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6
Q

what is the resting pressure of the UOS

A

30-200mmHg

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7
Q

what does the pressure in the UOS decrease (3 things)

A
  1. decreases the entry of air into the oesophagus and insufflating the stomach
  2. decreases reflux of the contents into the pharynx and larynx during oesophageal peristalsis
  3. decreases gastric reflux
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8
Q

how long does the UOS relax during the pharyngeal swallow

A

0.5-1s

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9
Q

what is primary peristalsis

A

initiated by swallowing

continuation of pharyngeal contraction

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10
Q

what is secondary peristalsis

A

not induced by swallowing
result of the stimulation of sensory receptors in the body of the oesophagus
involuntary

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11
Q

what is the nervous control of oesophageal peristalsis

A
  • parasympathetic and sympathetic NS (autonomic)
  • enteric nervous system= plexus of nerves embedded in the wall of the GI tract
  • —- submucosal plexus
  • —– myenteric nerve plexus
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12
Q

what is the resting pressure of the LOS

A

20-35mmHG

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13
Q

what is the action of the LOS

A

relaxes 1-2 sec after swallowing then hypercontracts

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14
Q

what happens immediately following the relaxation of LOS

A

receptive relaxation of the fundus of the stomach

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15
Q

when else does the LOS contract

A

relaxes unrelated to swallowing- transiently when upright- mediated by the vagus nerve- releases air from the stomach

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16
Q

what are the 3 phases of swallowing

A

`1. oral phase

  1. pharyngal phase
  2. oesophageal phase
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17
Q

is the oral phase voluntary or involuntary

A

voluntary

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18
Q

what are the 2 subphases of the oral phase

A
  1. prepartory phase- mastication, saliva

2. transfer phase- food propelled into pharynx

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19
Q

is the pharyngeal phase voluntary or involuntary

A

involuntar

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20
Q

what type of muscle is in the oral phase, pharyngeal phase, oesophageal phase

A

oral- striaged
pharyngeal- striated
oesophageal- smooth

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21
Q

what is involved in the pharygeal phase

A

bolus enters pharynx and descends through the pharynx by peristalsis
UOS relaxes and bolus leaves pharynx

22
Q

in the pharyngeal phase which 3 passages have to be closed and how are they closed

A
  1. mouth- tongue pushes against palate sealing off back of mouth
  2. upper airway- soft palate elevates and the proximal pharyngeal wall moves medially
  3. lower airway- closed by the epiglottis swinging down and the vocal cords and arytenoids adducting
23
Q

is the oesophageal phase volunatary or involuntary

A

involuntary

24
Q

what happens in the oesophageal phase

A

UOS relaxes, bolus enters oesophagus, oesophageal persitalsis initiated

25
Q

what makes up the superior border of the oral cavity

A

hard palate and soft palate

26
Q

what makes up the inferior border of the oral cavity

A

geniohyoid and mylohyoid muscles supporting the floor of the mouth

27
Q

what makes up teh anterior and lateral borders of oral cavity

A

labium (lip)
cheek
body of tongue

28
Q

what makes of up the post border of oral cavity

A

uvula
tonsils (palatine and lingual)
root of tongue

29
Q

what are the cavities descending down from the nasal cavity

A

nasal cavity - nasopharynx - oropharyx- hypopharynx- oesophagus

30
Q

what is gastro-oesophageal reflux disease

A

an extension of what is a normal physiological process
the LOS usually transiently opens outside swallowing however this become unregulated and leads to symptoms

ie when LOS relaxations become tooo frequent resulting in symptoms

As a result gastric contents move into the oesophagus which is erosive to the oesophagus and damages the epithelim

31
Q

what are other contributing mechanisms to GORD

A
  • disordered gastric motility= more acid in fundus region of stomach
  • hiatus hernia = when there is a reservoir of acid close to teh LOS which may impair its funcitoning
  • impaired oesophageal peristalsis- reduced clearance
  • hypotensive LOS= LOS doesn’t contract tightly enough
32
Q

what is a hiatus

A

an opening in the diapragm where the oesophagus passes through to join the stomach

the diaphragm acts as additioanl suppport ( like a sphincter contracting aroudn teh GO junction

33
Q

what is a hernia

A

when part of an organ protrudes through an opening in the muscle tissue meant to hold it in place

34
Q

a hiatus hernia is?

A

when part of the stomach bulges up into the chest through the hiatus

35
Q

why do symptoms occur in GORD

A

The pH in the oesophagus is normally 6-7 but in the stomach the contents are 1-2 (without being buffered by food)
the squamous epithelium in the oesophagus can’t handle the pH of the gastric contents -

OESOPHAGEAL NERVE FIBRES GIVE A SENSTION OF BURNIGN DISCOMFORT

36
Q

what are the 2 complications of GORD

A
  1. oesophageal stricture

2. Barrett’s oesophagus

37
Q

what is oesophageal stricture

A

= scarring from repeated acid exposure and ulcreation which leads to dysphagia (difficulty swallowing) often fibrous

38
Q

what is Barrett’s oesophagus

A

= damage to the oesphageal epithelium by chronic acid expsure. change from squamous–> columnar lined epithelium (intestinal metaplasia)
Barrett’s is a risk factor for oesophageal cancer (adenocarcinoma)

39
Q

describe the progresssio of Barrett’s to cancer

A

squamous oesophagus –> chronic inflammation –> barretts metaplasia –> low grade dysplasia –> high grade dysplasia –> invasive adenocarcinoma

40
Q

what are the 2 types of oesophageal cancer

A
  1. adenocarcinoma

2. squamous oesophagus

41
Q

describe the adenocarcinoma variant of oesophageal ancer

A

more common in western countries
more likely to be in the distal oesophagus (GO junction)
GORD –> Barrett’s –> cancer

42
Q

describe the squamous cell carinoma variant of oesphageal cancer

A

due to smoking, alcohol, diet

more likely to be higher up in the oesophagus

43
Q

what are the 2 categories of oesophageal conditions

A
  1. structural= anatomic abnormaility

2. motility= problem with nerves and muscle

44
Q

what are some examples of structural oesophageal conditions (8)

A

ZAC UR ERS

  1. Zenker’s diverticulum
  2. adenocarcinoma
  3. oesophageal candidas
  4. Ulceration
  5. Ring/web
  6. Eosinophilic oesophagitis
  7. Reflux oesophagitis
    S. Stricture
45
Q

what is ring/web

A

on the internal aspect of the oesphagus causing obstruction

membrane grows inwards and constricts lumen

46
Q

what is eosinophilic oesophagitis

A

when the eosinophils infiltrate the epithelium of the oesophagus

47
Q

what is Zenker’s diverticulum

A

the faliure of the UOS to relax causing a build up in pressure in the pharynx

if the oesphageal wall is already weakened it may bulge outwards

This then creates a pouch which food can get stuck in

48
Q

what are the 3 motility oesophageal conditions

A

DAS

  1. Diffuse oesophageal spasm
  2. Achlasia
  3. Schleroderma
49
Q

what is diffuse oesophageal spasm

A

non- peristaltic or simultaneous onset of contractions in the oesophagus

ie corckscrew oesophagus

50
Q

what is achlasia

A

degeneration of nerves in the oesophagus

  • ganglionic cells in the myenteric plexus
  • loss of inhibitory neurons in LOS that switch off tonic contractions
51
Q

what is scleroderma

A

CT disease
hardening of the mucosa and submucosal layers
affects SM and nerves of oesophagus turning it into a rubbery hose

  • absent peristalsis= weak contractions= complete loss of los tome
  • severe dysphagia, severe reflux
52
Q

what is the difference between structural and motility oesophageal conditions

A

motility conditions are ore likely to present with dysphagia, be intermittent and may affect both solids and liquids

motility= problems with nerves and muslce
structural= problems with anatomy

DIGESTIVE (6 decks)

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