Abdomen 1 - Viscera

Question 1

what is an anatomical sphincter?

Answer 1

visible, thickened ring of circular muscle that physically constricts to regulate the passage of contents

Question 2

what is a physiological sphincter?

Answer 2

functional sphincter without a distinct thickening of muscle, relying on surrounding structures

Question 3

what type of sphincter is the lower oesophageal sphincter - anatomical or physiological?

Answer 3

physiological

Question 4

what does the Z-line in the oesophagus signify? when is this clinically significant?

Answer 4

Z-line marks a distinct change between oesophageal and gastric mucosa

clinical: blurry Z-line suggests chronic GERD (acid reflux) = risk of Barrett’s oesophagus & oesophageal cancer

Question 5

describe the change in muscle composition o the oesophagus from upper to lower 1/3s

Answer 5

upper 1/3 = purely skeletal muscle (under voluntary control)

middle 1/3 = mixed skeletal & smooth muscle (transition zone)

lower 1/3 = smooth muscle (involuntary control)

Question 6

course of the oesophagus?

Answer 6

starts at C6 (where the laryngopharynx ends) - travels through posterior mediastinum & through diaphragm at T10

ends at cardiac orifice of the stomach

Question 7

what passes through the oesophageal hiatus at T10 along with the oesophagus?

Answer 7

right & left vagus nerves
- right vagus nerve becomes posterior vagal trunk
- left vagus nerve becomes anterior vagal trunk

Question 8

what arteries supply the upper, middle & lower 1/3s of the oesophagus?

Answer 8

upper = inferior thyroid artery (branch of external carotid)
middle = oesophageal branches (directly from thoracic aorta)
lower = left gastric artery (from coeliac trunk)