Esophagus

Introduction

Outer layer of longitudinal muscle, and an inner layer of cicrular muscle. There is no serosa

18-24 cm long.

Upper esophageal sphincter (cricopharyngeus muscle) just below 15 cm below incisors

lower esophageal sphincter 40 cm below incisors

Squamous epithelium, whitish in colour; the Z line at the GE junction denotes the transition to reddish mucosas

The esophagus is a hidden

Voluntary prox

Blood supply is from thyroid artery

middle supply from the thoracic vessels

distal esophagus is vascularized by the lesser curvature of the stomach

innervation is from the vagus nerve

Veins: portal/systemic anastamosis (important for liver disease

Arch of aorta crosses esophagus, creating an indentation

Peristalsis in the esophagus is responsible for moving food from the mouth to the stomach.

The medulla controls the swallow reflex via vagus and glossopharyngeal nerves.
The cricopharyngeus forms the upper sphincter.
The nasopharynx closes, inhibiting breathing.
Laryngeal muscles contract to close the glottis and elevate the larynx.
Peristalsis begins in the pharynx to propel bolus down.
Lower sphincter contraction releases to allow the bolus to enter. It relaxes as the swallowing reflex begins and contracts again as the peristaltic waves passes by

The esophageal pH should normally be ~7. It should be >4 over 95% of the time; if it is acidic more than this, it suggests