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DS > Lecture 7 > Flashcards

Lecture 7 Flashcards

1
Q

Describe swallowing?

A

It is a highly complex reflex, that needs to be preciser else choking and aspiration can occur.

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2
Q

What are the three phases of swallowing?

A
  1. Oral.
  2. Pharyngeal.
  3. Oesophageal.
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3
Q

What are the motor and sensory component of swallowing in the oral phase?

A

It is a voluntary control. The muscles are striated.

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4
Q

What are the motor and sensory component of swallowing in the pharyngeal phase?

A

It is an involuntary control. The muscles are striated.

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5
Q

What are the motor and sensory component of swallowing in the oesophageal phase?

A

It is an involuntary control. the muscles are striated and smooth.

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6
Q

What is swallowing controlled by?

A

Both cortex and brainstem (medulla).

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7
Q

What happens at the swallowing centre?

A

The swallowing centre in the brainstem receives sensory input from receptors in posterior mouth and upper pharynx and also innervates swallowing muscles via cranial nerves.

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8
Q

What is the anterior and lateral boundary of the oral cavity?

A

Labium (lip).
Cheek.
Body of the tongue.

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9
Q

What is the superior boundary of the oral cavity?

A

Hard palate.

Soft palate.

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10
Q

What is the inferior boundary of the oral cavity?

A

The geniohyoid and mylohyoid muscles supporting the floor of the mouth.

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11
Q

What is the posterior boundary of the oral cavity?

A

Uvula.
Palatine tonsil.
Root of the tongue.
Lingual tonsil.

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12
Q

How many phases does the oral phase consist of?

A
  1. Preparatory phase - formation of the bolus.

2. Transfer phase - bolus is propelled into the pharynx.

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13
Q

What is mastication of the oral preparatory phase?

A

Food is broken down into size, shape and consistency suitable for transport.

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14
Q

What do the teeth, tongue and cheeks do in the mastication of the oral preparatory phase?

A

Teeth = They grind the food down.

Tongue, cheeks = position solids over the grinding surfaces.

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15
Q

What does saliva do in the oral preparatory phase?

A

It lubricates and helps dissolve the food.

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16
Q

What happens in the oral transfer phase?

A

The tip of the tongue moves into contract with the hard palate, it closes off the anterior oral cavity. The bolus is then pushed into the back of the mouth.

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17
Q

How long does the pharyngeal phase last for?

A

Slightly less than 1 second.

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18
Q

What has to be closed for the pharyngeal to work?

A

Mouth.
Upper airway.
Lower airway.

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19
Q

Where does the bolus enter and exit in the pharyngeal phase?

A

Pharynx from the back of the mouth and exits the upper oesophageal sphincter.

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20
Q

What is the 1st step of the pharyngeal phase?

A

The tongue pushes against the palate to seal the back of the mouth i.e. oropharynx.

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21
Q

What is the 2nd step of the pharyngeal phase?

A

The soft palate elevates and proximal pharyngeal wall moves medially to seal off the upper airway i.e. nasopharynx.

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22
Q

What is the 3rd step of the pharyngeal phase?

A

The epiglottis swings down and vocal cords and arytenoids adduct to seal off the lower airway i.e. laryngeal vestibule leading into the trachea.

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23
Q

How fast does bolus descent through the pharynx?

A

30-40cm/s via peristalsis.

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24
Q

What is the Upper Oesophageal Sphincter (UOS) composed of?

A

Group of muscles, which act as a barrier between the pharynx and the oesophagus.

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25
Q

What is the UOS doing most of the time?

A

Contracting and closed.

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26
Q

What is the normal pressure when the UOS is contracted?

A

30-200mmHg.

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27
Q

What does the UOS prevent?

A
  1. Air insufflating (distending) the stomach.

2. Reflux of contents into the pharynx and larynx during oesophageal peristalsis.

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28
Q

What happens to UOS during swallowing?

A

When it relaxes it opens. UOS also opens when belching or vomiting.

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29
Q

What does the UOS consist of?

A

Cricopharyngeus.
Inferior pharyngeal constrictor.
Cervical oesophagus.

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30
Q

How does the UOS close?

A

When it is resting, via tonic contraction.

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31
Q

How long does UOS stay open for?

A

0.5seconds.

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32
Q

What causes UOS to open (especially during swallowing)?

A

The cricopharyngeus relaxes, the supra hyoid and thyroid muscles contract. The pressure of the descending bolus distends the UOS.

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33
Q

Where does the oesophagus run from?

A

It extends from the upper oesophageal sphincter (UOS) to the lower oesophageal sphincter (LOS).

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34
Q

How long is the oesophagus?

A

20-25cm long. It depends on how tall the person is.

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35
Q

What is the mucosa of the oesophagus?

A

Stratified squamous epithelium.

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36
Q

What is the muscle of the upper 1/3 of the oesophagus?

A

Striated muscle.

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37
Q

What is the muscle of the lower 2/3 of the oesophagus?

A

Smooth muscle.

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38
Q

What is the 1st step of the oesophageal phase?

A

The UOS relaxes, bolus enters the oesophagus, and oesophageal peristalsis is initiated.

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39
Q

What is primary peristalsis in the oesophageal phase?

A

It is initiated by swallowing. It is a continuation of pharyngeal contraction wave. It’s slower than pharyngeal peristalsis: 3-5cm/s.

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40
Q

What is secondary peristalsis in the oesophageal phase?

A

It is initiated by distension (e.g. food stuck or gastric acid). Stretch receptors are stimulate, this initiates local reflex response triggering peristalsis.

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41
Q

What are the plexuses embedded in the wall of the GI tract?

A 
Submucosal plexus (in the submucosa).
Myenteric plexus (between circular and longitudinal muscles).
42
Q

What can the enteric nervous system do?

A

It can operate autonomously - coordination of reflexes. It can also communicate with Parasympathetic and sympathetic nervous systems.

43
Q

What happens to the longitudinal muscle layer in the oesophagus during peristalsis?

A

The oesophagus shortens.

44
Q

What does the circular muscle layer in the oesophagus do during peristalsis

A

Contraction above and relaxation below the bolus.

45
Q

What is the squamocolumnar junction?

A

The junction between the oesophagus and the stomach.

There is a transition between stratified squamous (oesophagus) and columnar (gastric) epithelium.

46
Q

What is the squamocolumnar junction also known as?

A

Z line.

47
Q

Where is the Lower Oesophageal Sphincter (LOS)?

A

It is close to the squamocolumnar junction.

48
Q

What is the LOS?

A

It is a specialised segment of smooth muscle.

49
Q

What happens when LOS is contracted?

A

It is closed. This is most of the time. Normal pressure is 20-35mmHg.

50
Q

What happens to LOS after swallowing?

A

It begins to relax 1-2s after swallowing. It will stay in the relaxed state for 5-10s, followed by hyper contraction.

51
Q

What happens when LOS relaxes transiently?

A

LOS can relax when you’re not swallowing, it can be physiological. It occurs at regular intervals and only in the upright position. It is mediated by the vagus nerve, and releases air from the stomach.

52
Q

What is a 24hr pH study?

A

A thin catheter is entered into a persons oesophagus for 24 hours. A drop in pH will indicate reflux.

53
Q

What is manometry?

A

It’s similar to a pH study, except it does not last for 24 hours. The patient will perform swallows with water, and a thing catheter with pressure sensors sits in the oesophagus. The contraction will measure as a wave.

54
Q

How are structural oesophageal diseases characterised?

A

They are diseases that cause:

Visible changes.
Inflammation.
Ischaemia/necrosis. 
Ulceration.
Bleeding.
Narrowing.
Masses.
Diverticulum.
55
Q

How are dysmotility oesophageal diseases characterised?

A

It is abnormal contraction of oesophageal muscles.

56
Q

How are functional oesophageal diseases characterised?

A

they are disorders of motility, sensation, and brain-gut function.

57
Q

What is gastro-oesophageal reflux?

A

The movement of gastric contents into the oesophagus.

58
Q

What do the gastric contents contain?

A

Acid which is erosive to the oesophagus.

59
Q

When does reflux occur?

A

During transient reaction of LOS.

60
Q

Describe the physiological side to Transient LOS relaxation?

A

Air is let out of the stomach. It becomes pathological when too much gastric juice also refluxed into the oesophagus, causing symptoms and diseases.

61
Q

What causes hypotension in LOS (where LOS is not contracting tight enough)?

A 
Caffeine.
Alcohol.
Chocolate.
Fats.
Certain medications e.g. beta-blockers, nitrates, calcium and channel blockers.
62
Q

What else contributes to GORD?

A

Hiatus hernia, however not all people with hiatus hernia have reflux.
Impaired oesophageal peristalsis, where there is reduced clearance.

63
Q

What is the hiatus?

A

It is an opening in the diaphragm, where the oesophagus passes through to join the stomach.

64
Q

How does the diaphragm act as additional support?

A

It constricts the oesophagus around the GO junction.

65
Q

What happens in a hiatus hernia?

A

The stomach passes through the hiatus into the chest. Thus the GO junction has lost support from the diaphragm.

66
Q

What are symptoms of acid reflux?

A
  1. Heartburn/chest discomfort - burning sensation or discomfort over the chest.
  2. Regurgitation - food or liquid comes back up into the mouth.
  3. Sour or bitter taste in the mouth.
67
Q

when may acid reflux be worse?

A

After eating or lying down e.g. bed time.

68
Q

What causes the symptoms?

A

The gastric acid comes into contact with the oesophagus. The normal range of pH in the oesophagus is 6-7, the mucosa is sensitive to acidic pH. The pH of gastric juice is 1-2 (unless buffered by food). The nerve fibres in the oesophagus are sensitive to acidic pH, thus giving “burning sensation”.

69
Q

What can GORD be viewed as?

A

Disease due to abnormal motility of the oesophagus and stomach.

70
Q

What is reflux oesophagi’s?

A

Damage to the oesophageal mucosa by reflux leading to inflammation, ulceration and bleeding.

71
Q

What is a peptic stricture?

A

Prolonged inflammation of oesophageal mucosa by reflux, this can lead to fibrosis and scarring.

72
Q

what else can GORD cause?

A

Barrett’s oesophagus and cancer.

73
Q

What is dysphagia?

A

Difficulty in swallowing.

74
Q

What can cause Barrett’s Oesophagus?

A

Damage to oesophageal epithelium by chronic acid exposure from GORD, which can lead to Barrett’s oesophagus.

75
Q

What happens to the epithelium in Barrett’s Oesophagus?

A

The oesophageal epithelium (squamous epithelium) becomes like gastric epithelium (columnar epithelium with goblet cells). Known as Intestinal metaplasia.

76
Q

Who is at high risk of Barrett’s oesophagus?

A

Male, >50, increased BMI, smoker with chronic GORD>

77
Q

What can Barrett’s oesophagus cause?

A

It gives an increased risk of oesophageal adenocarcinoma.

78
Q

Describe the evolution from Barrett’s Oesophagus to Cancer?

A
  1. Injury to the squamous epithelium, caused by acid and bile reflux or Nitrous oxide.
  2. Chronic inflammation, could be due to Genetics, gender, race and other factors (cox-2).
  3. Barrett’s metaplasia.
  4. Low-grade dysplasia.
  5. High-grade dysplasia.
  6. Invasive adenocarcinoma.
79
Q

What are the types of oesophageal cancer?

A
  1. Adenocarcinoma (adenoCa).

2. Squamous cell carcinoma (SqCC).

80
Q

What can cause adenoCa?

A

GORD - risk of Barrett’s - risk of oesophageal adenoCa.

81
Q

What can cause SqCC?

A

Smoking, alcohol, diet - risk of oesophageal SqCC.

82
Q

What type of oesophageal cancer is more common in Western countries?

A

adenoCa.

83
Q

What is the difference between SqCC and adenoCa?

A

adenoCa more likely to be in distal oesophagus/GO junction.

SqCC is more likely to be higher up int he oesophagus.

84
Q

What is ring/web of the oesophagus?

A

It is a thin membrane called the schatzki ring. It is found distally and typically associated with a hiatus hernia, aetiology uncertain.

85
Q

What is Zener’s diverticulum?

A

a.k.a pharyngeal pouch.
Where excessive pressure causes the weakest portion of the pharynx to balloon out. You get poor swallowing, impaired relaxation of cricopharynxgeus. More common in elderly.

86
Q

What is a stricture of the oesophagus?

A

Peptic stricture = reflux related.
Caustic stricture = caustic injury post-radiotherapy.
Post surgical stricture = anatomic malignant.

87
Q

What is reflux oesophagi’s?

A

GORD can result in severe erosive oesophagitis or a stricture.

88
Q

What is oesophageal candidiasis?

A

White plaques coating the oesophagus.

89
Q

What is an oesophageal ulceration?

A

Ulcers in the oesophagus. Herpes simplex virus, cytomegalovirus are viruses that can cause it. Or pills can cause ulceration i.e. doxycycline, or bisphosphonates.

90
Q

What is eosinophilic oesophagi’s?

A

Eosinophils infiltrate the epithelium of the oesophagus. It is allergy-mediated. The patient may have a history o atopy: asthma, hay fever or eczema.

91
Q

What happens in a motility disorder of the oesophagus?

A

The person will have difficulty swallowing - dysphagia.

92
Q

What are the symptoms of motility disorders?

A

They’re more likely to be intermittent and have variable symptoms.

93
Q

What can motility disorders affect?

A

Liquids as musch as solids. Where as structural disorder affect solids mainly.

94
Q

What is the problem in motility disorders?

A

There is a problem with innervation to the smooth muscle (loss of function or loss of co-ordination) or direct muscle damage.

95
Q

What is achalasia?

A

Loss or peristalsis in the distal oesophagus and failure of LOS to relax with swallowing.

96
Q

What happens in Achalasia to cause loss of peristalsis?

A

Degeneration of nerves in the oesophagus: myenteric plexus, LOS inhibitory nerves. the cause is uncertain.

97
Q

What is a diffuse oesophageal spasm?

A

Non-peristaltic or simultaneous onset of contractions in the oesophagus. It can cause chest pain.

98
Q

What it is nutcracker oesophagus?

A

It is normal peristalsis, but the contractions have a very high amplitude i.e. the wave of contractions propagate down the oesophagus normally but are just too strong.

99
Q

What type of disease is scleroderma?

A

It is a connective tissue disease. Where there is hardening (fibrosis) of the connective tissue.

100
Q

What happens when scleroderma affects the oesophagus?

A

Damage occurs to the submucosa, muscle layers, nerves, the oesophagus turns into a rubbery hoes-pipe.
Peristalsis is absent, contractions are weak and LOS has no tone.
In addition to dysphagia, severe reflux can occur.

DS (32 decks)

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