Esophagus

Question 1

What is the esophagus?

Answer 1

A tube that carries food, liquid, & saliva from the pharynx to stomach

Question 2

Esophagus anatomical course?
#1

Answer 2

1. Begins at C6 (cricoid cartilage inferior border) in neck (continuous with laryngopharynx superiorly)

Question 3

Esophagus anatomical course?
#2

Answer 3

2. Descends downwards into sup. mediastinum of thorax, b/w trachea and vertebral bodies of T1 - T4

Question 4

Esophagus anatomical course?
#3

Answer 4

3. Enters abdomen via esophageal hiatus (opening in right crus of diaphragm) at T10

Question 5

Esophagus anatomical course?
#4

Answer 5

4. It terminates in the abdominal portion at T11 by joining the cardiac orifice

Question 6

Label its anatomical structure from innermost to outermost

Answer 6

1. Mucosa
2. Submucosa ( along w Meissner’s/submucosal plexus)
3. Muscular layer (externa)
   (Inner circular layer, auerbach’s / myenteric plexus, outer longitudinal)
4. Adventitia / Serosa

Question 7

What sort of epithelium does its mucosa have?

Answer 7

Stratified Squamous (non-keratinised)

Question 8

What sort of muscles are present in the 3 divisions of longitudinal muscle (sup, middle, inf)?

Answer 8

Sup: voluntary striated muscle

Middle: voluntary striated muscle + smooth muscle

Inf: smooth muscle

Question 9

Is it entirely adventitia or serosa too?

Answer 9

It has both, but the outer distal & intraperitoneal region is serosa

Question 10

In what week is the esophagus developed?

Answer 10

4th week

Question 11

What layer of the gut is it formed by?

Answer 11

Foregut

Question 12

Explain the embryological development of the esophagus

Answer 12

1. In the 4th week, the foregut forms the oesophagus (dorsally) and trachea (ventrally) by the tracheoesophageal folds, which in turn fuse to form the tracheoesophageal septum

Question 13

What layer is the epithelium formed by

Answer 13

Endoderm

Question 14

What layer forms the glands

Answer 14

Endoderm

Question 15

What forms the striated muscle

Answer 15

Mesenchyme of caudal pharyngeal arches

Question 16

Which layer forms the smooth muscle

Answer 16

Splanchnic mesenchyme (mesoderm)

Question 17

How does the oesophagus grow embryologically?

Answer 17

With the descent of heart and lungs it also extends

Question 18

Food is transported via?

Answer 18

Peristalsis

Question 19

What is peristalsis

Answer 19

Rhythmic contractions of muscles which propagate food downwards

Question 20

If peristaltic muscles harden or get damaged, it would lead to?

Answer 20

Difficulty in swallowing = Dysphagia

Question 21

How many oesophageal sphincters are there and name them

Answer 21

2, upper and lower

Question 22

What do the oesophageal sphincters do?

Answer 22

Prevent air entry and gastric acid reflux via upper and lower respectively

Question 23

Location, muscle type, function and muscle name, as well as normal muscle state and why of Upper Oesophageal sphincter

Answer 23

At junction between pharynx and oesophagus
Striated muscle
Prevents air entry
Via cricopharyngeus
Normally, constricted to prevent air entrance into oesophagus

Question 24

Location, muscle type, and function of Lower Oesophageal sphincter at rest and

Answer 24

Located at gastro-oesophageal junction (Left to T11 vertebra)
Not muscle type but rather a physiological sphincter
At rest, prevents gastric acid reflux and during peristalsis, allowed to relax to let food enter stomach

Question 25

How is the change of the LES marked?

Answer 25

By changing from oesophageal to gastric mucosa (Stratified Squamaous -> Simple Columnar)

Question 26

Since the LES is physiological, how many factors is it maintained by and name them (ACMP)

Answer 26

4 factors 1. Oesophagus enters stomach at an *acute* angle 2. Walls of intra-abdominal sections of oesophagus are *compressed* when there is a positive intra-abdominal pressure 3. Prominent *mucosal folds* at gastro-oesophageal junction aid in occluding lumen. 4. Right crus of diaphragm has a *pinch-cock* effect

Question 27

How many anatomical relations lead to physiological constrictions in its lumen and name them (ABCD)

Answer 27

4 relations 1. Arch of Aorta 2. Bronchus (Left main stem) 3. Cricoid Cartilage 4. Diaphragmatic hiatus

Question 28

Arterially, Thoracic supply of oesophagus is done by:

Answer 28

1. Branches of Thoracic Aorta 2. Inferior Thyroid Artery ( branch of thyrocervical trunk)

Question 29

Venius drainage of thoracic region is done by and what do they drain into

Answer 29

1. Azygous Vein 2. Inferior Thyroid Vein They drain into systemic circulation

Question 30

Arterial abdominal supply?

Answer 30

1. Left gastric artery 2. Left inferior phrenic artery

Question 31

Venous abdominal supply and drainage into?

Answer 31

1. Into portal circulation via left gastric artery 2. Into systemic circulation via azygous vein

Question 32

Portal and systemic circulation drainage form a:

Answer 32

Porto-systemic anastomosis

Question 33

Innervation of it is done by which plexus

Answer 33

Oesophageal plexus

Question 34

Oesophageal plexus is formed by union of what? ( OP = PVT + Sym from C & T Sts)

Answer 34

1. Parasympathetic vagal trunks 2. Sympathetic fibers from: A. Cervical B. Thoracic sympathetic trunks

Question 35

How many types of sympathetic fibers do the vagal trunks have?

Answer 35

2 different types

Question 36

Upper oesophageal sphincter + upper striated muscles supplied by what nerve/cell fibers?

Answer 36

Nucleus Ambiguus

Question 37

Upper oesophageal sphincter + upper striated muscles supplied by what nucleus?

Answer 37

Nucleus Ambiguus

Question 38

Lower Oesophageal Sphincter and Lower smooth muscles supplied by what nucleus?

Answer 38

Dorsal Motor Nucleus

Question 39

Lymphatic drainage of sup 1/3?

Answer 39

Deep cervical lymph nodes

Question 40

Lymphatic drainage of mid 1/3?

Answer 40

Superior & Posterior Mediastinal nodes

Question 41

Lymphatic drainage of inferior 1/3?

Answer 41

Left gastric & Celiac Nodes

Question 42

Disorders of the oesophagus? (3)

Answer 42

1. Barrett's 2. Oesophageal carcinoma 3. Oesophageal varices

Question 43

What is barretts oesophagus and how is it caused and how is it detected?

Answer 43

Metaplasia of the LES's stratified squamous epithelium to gastric columnar epithelium Caused by chronic acid exposure due to malfunctioning LES Detected via endoscopy

Question 44

Features and types of Oesophageal carcinoma?

Answer 44

Features: 1. Dysphagia 2. Weight loss Types: 1. Squamous Cell Carcinoma - common and occurs at any level 2. Adenocarcinoma - only in inferior 1/3, associated with Barrett's

Question 45

What are Oesophageal varices, why do they occur, what is it also known as, and what do most patients present it with?

Answer 45

When the abdominal oesophagus drains into portosystemic circulation and leads to abnormally dilated submucosal veins Occurs due to pressure increase beyond normal in portal system and secondary to chronic liver disease such as cirrhosis and portal vein obstruction Aka Portal Hypertension Patients present with Haematemesis (Puking blood)