Lecture 8 - upper GIT

Question 1

Upper GIT content:

Answer 1

• Oesophagus
• Stomach
  Small intestine

Question 2

Oesophagus:

Answer 2

• Fibromuscular tube, transports food from pharynx to stomach

Question 3

esophagus is found in the

Answer 3

post and sup mediastinum

Question 4

Esophagus Originates at the

Answer 4

lower border of cricoid cartilage (C6)

Question 5

Esophagus goes through

Answer 5

• Goes through oesophageal hiatus at T10
• And then enters cardiac orifice of the stomach at t11

Question 6

As the esophagus descends downward in post mediastinum, it is first:

• Then proceeds in inferior mediastinum:

Answer 6

posterior to the trachea, but ant to the vert bodies

ant to vert bodies, the aorta first crosses ant to it and then proceeds behind it

Question 7

Divisions of the oesophagus

Answer 7

• Cervical
• Thoracic
• Abdominal

Question 8

Histology of the esophagus

Answer 8

• On inside, consists of folded mucosa which
  Consists mainly of non-keratinized, stratified
  Squamous epithelium
• This is followed by a layer of sub mucosa

Question 9

muscles of the esophagus

Answer 9

• Outer longitudinal layer
• Inner circular layer
• Superior 1/3rd: Skeletal m
• Middle 1/3rd: Mixed
• Lower 1/3rd: Smooth
• Outer layer = adventitia, however in distal part and peritoneal part we don’t have an adventitia but a serosa

Question 10

4 Physiological constrictions of the esophagus, Acronym: ABCD

Answer 10

– A: Arch of the aorta (T4)
– B: Left main bronchus (T5)
– C: Cricopharyngeal muscle (upper esophageal sphincter) (C6)
– D: Diaphragm (T10)

Question 11

Esophagus relations:

Answer 11

• Left: arch of the aorta, descending aorta
• Right: azygous vein
• Posteriorly: vertebral bodies, descending aorta
• Anteriorly: trachea, left main bronchus, right pulmonary artery, pericardium and heart (left atrium), diaphragm

Question 12

Arterial supply of esophagus

Answer 12

• Divided into thoracic and abdominal parts
  Thoracic part receives arterial supply from: Thoracic aorta
  Upper part of esophagus; Sup and inf thyroid vessels
  Middle: Oesophageal branches of the descending aorta, azygous and hemiazygous venous system
  Lower (abdominal part): Left gastric vessels, inferior phrenic vessels

Question 13

Lymphatic drainage of esophagus

Answer 13

• Cervical: Inferior deep cervical nodes
• Thoracic: Tracheobronchial and posterior mediastinal nodes
• Abdominal: Left gastric and coeliac nodes

Question 14

Oesophagus: Innervation

Answer 14

Parasympathetic: Vagus n (CN X)
* Motor muscle and glands), pain
* Upper: recurrent laryngeal nn
* Middle and lower: Vagus n via oesophageal plexus
Sympathetic (T4-6)
* Pain
* Upper: middle cervical ganglia
* Middle and lower:
Thoracic sympathetic trunks and greater splanchnic nn

Question 15

Esophagus has 2 sphincters

Answer 15

– upper and lower esophageal sphincters

Question 16

Lower sphincter is a physiological sphincter –at junction between esophagus and stomach

Answer 16

AKA Gastro-esophageal junction
- Located to the left of T11 vert
- Z-line: non-keratinised stratified squamous epithelium changes to columnar epithelium

Question 17

How does sphincter work if no muscles to close it?

Answer 17

• Right crus of the diaphragm
• Angle of the oesophagus entering the stomach
• Zone of high pressure
• Longitudinal folds of the lower oesophageal mucosa
• Positive intra-abdominal pressure