Esophagus

Relationship with pharynx

Continues from larynogopharynx

3 parts of esophagus

• Cervical part

• Thoracici part

• Abdominal part

Cervical part of esophagus

• Location

• Location in relation of trachea

Location: Between longus colli and trachea

Location in relation of trachea: Left side of trachea at thoracic inlet

Thoracic part of esophagus

• Location

• Location in relation of trachea

• Passes via

• Location in relation to lungs and aorta

Location: From thoracic inlet to diaphragm

Location in relation of trachea: Returns dorsal to the trachea on dorsal mediastinum

Passes via: Dorsal trachea bifurcation, right side of artic arch and through esophageal hiatus

Location in relation to lungs and aorta: Between lungs and ventral to aorta

Abdominal part of esophagus

Short

Cervical Part of Esophgaus

Label 1-7

1. Common carotid artery

2. Vagosympathetic trunk

3. Esophagus

4. Trachea

5. Brachial plexus

6. Medial retropharyngeal lymph node

7. Thyroid gland

In which view, left lateral or right lateral can you clearly see the esophagus?

Right lateral view

What is the esophagus?

A muscular tube

What are the 3 layers of the esophagus wall?

• T. adventitia

• T. muscularis

• T. mucosa

T. Advantitia

• What kind of connective tissue

Connective tissue: Loose connective tissue that connecting adjacent structures to allow movement

T. Muscularis

• What kind of contraction

• Structure in

  • Dog & ruminent

  • Pig

  • Cat & horse

• What kind of contraction: Wavelike contraction to move bolus toward stomach

• Structure in:

  • Dog & ruminant: Entirely striated muscle

  • Pig: Has short part of smooth muscle near cardia

  • Cat & horse:

    • Cranial 2/3 striated muscle

    • Caudal 1/3 smooth muscle

T.mucosa

• Structure

• What is the epithelium like in T. mucosa?

• Structure like in

  • Dogs

  • Pig

  • Horse, ruminant and cat

Structure: Contains epithelium, lamina propria and lamina muscularis (submucosa)

Epithelium: Stratified squamous epithelium

Structure like in:

• Dogs: Submucosa that contains mucus glands over entire length of esophagus

• Pig: Glands only present in cranial half of esophagus

• Horse, ruminant and cat: Glands only present at pharynoesophageal junction

Why can’t horses vomit?

Because they have strong esophageal sphincter that allows one-way entry only

Blood Supply and Innervation

• Cervical part

  • Artery

  • Vein

• Thoracic part

  • Artery

  • Vein

• Innervation by

Artery and vein in:

• Cervical part:

  • Artery: Branch of common carotid artery

  • Vein: External jugular vein

• Thoracic part:

  • Artery: Bronchoesophageal artery (from thoracic aorta)

  • Vein: Bronchoesophageal vein (empty into azygous vein)

Innervation by: Vagus (parasympathetic) and thoracolumbar (sympathetic)