Oesophagus and its disorders

Question 1

Describe the anatomy of oesophagus?

Answer 1

Fibromuscular tube of striated squamous epithelium
Lies posterior to trachea
Begins at end of laryngopharynx + joins stomach a few cm from diaphragm
Beneath structure called cricoid cartilage

Question 2

What promotes transport of ingested food into stomach?

Answer 2

Highly coordinated muscular process; involves contraction + relaxation of oesophagus which transports food through GIT
Initiated by presence of food in pharynx + as food travels you have successive relaxation + contraction mediated vagus nerve. Sphincters innervates oesophagus
Relaxation of sphincters (UOS + LOS)

Question 3

What is function of upper oesophageal sphincter?

Answer 3

it will relax to allow food to go through + it will close immediately as food passes to prevent air entering into oesophagus

Question 4

What is function of lower oesophageal sphincter?

Answer 4

It will remain open for as long as swallowing is occurring + as soon food passes, it will close to prevent reflux of gastric contents from stomach into oesophagus as it will cause cells lining oesophagus to come off which is damaging

Question 5

Describe the muscle structure of oesophagus?

Answer 5

Skeletal muscles surround the oesophagus below the pharynx (upper third)
Smooth muscles surround lower two thirds

Question 6

What type of muscle is upper oesophageal sphincter?

Answer 6

Striated muscle

Question 7

What type of muscle is lower oesophageal sphincter?

Answer 7

Smooth muscle

Question 8

What are intrinsic components of LOS?

Answer 8

oesophageal muscles:

1. thick circular smooth muscle layers + longitudinal muscles
2. Clasp-like semi-circular smooth muscle fibres on right side
3. Sling like oblique gastric (Angle of His) muscle fibres on left side

Question 9

What are extrinsic components of LOS?

Answer 9

Diaphragm muscles:

• crural diaphragm encircles LOS + forms channel through oesophagus enters abdomen
• fibres of crural portion of diaphragm possess a pinchcock like action (extrinsic sphincter; diaphragmatic sphincter)

Question 10

Malfunction of intrinsic + extrinsic component of LOS leads to what disease?

Answer 10

Gastric oesophageal reflux disease (GORD

Question 11

Describe the innervation of oesophagus?

Answer 11

involvement of cholinergic ( i.e. via Ach) and non- cholinergic, NANC (e.g. both NO + VIP) innervation in control of tone of LOS
Neural control of oesophageal sphincter : ACh + substance P: contraction of intrinsic sphincters, NO + VIP: relax intrinsic sphincters

Question 12

What innervates upper part of oesophagus?

Answer 12

Vagus nerve

Splanchnic nerves

Question 13

What innervates lower part of oesophagus?

Answer 13

innervated by visceral motor neurons of vagus nerve with interruptions

Question 14

Describe oesophageal motor innervation?

Answer 14

Upper part is striated -> much of that is contracted providing no swallowing is occurring. Ach is important in this
Lower part is smooth muscle-> we have contraction + relaxation occurring dependent on context. VIP, NO + Ach is involved

Question 15

What is function of oesophagus?

Answer 15

Swallowing (deglutition)

conveys food+ fluids from pharynx to stomach

Question 16

What is swallowing triggered by?

Answer 16

afferent impulses in trigeminal (5th cranial nerve), glossopharygneal (important in taste) + vagus nerves

Question 17

How is swallowing initiated?

Answer 17

1. Voluntary action - collect material on tongue +push it backwards into pharynx
2. Waves of involuntary contractions push material into oesophagus

Question 18

Describe the passage in which food moves in body?

Answer 18

Mouth -> oropharynx -> laryngopharynx -> oesophagus + stomach

Question 19

What are reflex responses of swallowing?

Answer 19

Inhibition of respiration (breathing) - nasopharynx is closed off
Closure of glottis (around vocal cords by epiglottis -> prevents food entering trachea
Ring of peristaltic waves behind material move it towards stomach
Second wave of peristalsis moves any food remnants along -> called secondary peristalsis

Question 20

Swallowing is coordinated …

Answer 20

coordinated opening + closing of UOS + LOS

Question 21

What prevents reflux of gastric contents?

Answer 21

1. LOS- closes after material has passed
2. Pinchcock effect of diaphragmatic sphincter on lower oesophagus
3. Plug like action of mucosal folds in cardia - occludes lumen of gastro-oesophageal junction

Question 22

What are types of oesophageal disorders?

Answer 22

Achalasia
Regurgitation 
Aphagia
oesophageal spasm 
Diffuse oesophageal spasm

Question 23

What is aetiology of achalasia?

Answer 23

• disorders of motility or peristalsis of oesophagus
• damage to innervation of oesophagus
• degenerative lesions to vagus nerve + loss of myenteric plexus ganglionic cells in oesophagus

Question 24

What are symptoms of achalasia?

Answer 24

dysphgia -> difficult or painful swallowing
vomitting
Heartburn

Question 25

What is diagnosis of achalasia?

Answer 25

evaluate any swallowing disorders: patient history examination
Patient’s self report may suggest type of disorder responsible for complaints which may trigger tests required to determine or verify specific cause of compliant

Question 26

What are the reasons why oesophageal monometry?

Answer 26

To determine cause of non-cardiac chest pain
To evaluate cause of reflux (regurgitation) of stomach acid and other contents back up into oesophagus (GORD?)
To determine cause of difficulty with swallowing food (does UOS/LOS contract and relax properly?)

Question 27

What is reflux?

Answer 27

is retro-grade movement of gastric content into oesophagus due to relaxation of LOS?
- in normal individuals, reflux is often brief, relatively infrequent

Question 28

What are causes of reflux in those with GORD?

Answer 28

Transient spontaneuous LOS relaxation
Resting LOS pressure is too weak to resist pressure within stomach
Sudden relaxation of LOS that is not induced by swallowing

Question 29

What are factors that contribute to severity of GORD?

Answer 29

Weak or uncoordinated oesophageal contractions
Length of time oesophagus is exposed to gastric acid
Amount of pressure placed on anti-reflux barrier

Question 30

What is factors associated with GORD?

Answer 30

Pregnancy or obesity
Fat, chocolate, coffee or alcohol ingestion
large meals ,tomatoes, orange juice, onions
cigarette
Drugs