Upper GI

1. GASTRO INTESTINAL
SYSTEM

2. The Gastro intestinal tract of an adult is about 9m long and
extends from the oral cavity to the mouth.
 Regions of GI tract can be broadly classified into
1. Oral cavity
2. Pharynx
3. Oesophagus
4. Stomach
5. Small intestine and
6. Large intestine
Image source: Kent, M. V. , Ward. R., & Sidney, L.P. (2013), Schaum’s Outline of Human Anatomy and
Physiology. (4th ed.). Retrieved from http://accessengineeringlibrary.com.ezproxy.cdu.edu.au/browse/
schaums-outline-of-human-anatomy-and-physiology-fourth-edition

3.  Accessory digestive organs include teeth,
tongue, salivary glands, liver, gallbladder and
pancreas

4. Area of the digestive tract extending from the
pharynx upto stomach is called oesophagus
Resting length of adult oesophagus ranges from
18 to 26cm.
At the T10 vertebral level, the oesophagus
passes through the diaphragmatic hiatus and
enters into the cardia of the stomach at an
oblique angle.

5. Stomach
Cardia is the upper narrow region
immediately (1-2cm segment)
below the gastro-oesophageal
sphincter. Fundus is the superior portion
of the stomach lying above and slightly
posterior to the rest of the stomach.
Body is the large central portion.
Pylorus is the funnel-shaped terminal
portion that contains pyloric sphincter.
Image source: Kent, M. V. , Ward. R., & Sidney, L.P. (2013), Schaum’s Outline
of Human Anatomy and
Physiology. (4th ed.). Retrieved from
http://accessengineeringlibrary.com.ezproxy.cdu.edu.au/browse/
schaums-outline-of-human-anatomy-and-physiology-fourth-edition

7. Stomach and duodenum have 4 tissue layers
1. Mucosa – secretion and absorption
2. Submucosa – absorption of nutrients and
fluids in to capillaries
3. Muscularis propria – segmental contractions
and peristalsis
4. Serosa – binding and protection

8. Gastric mucosa is divided into epithelium, lamina propria
and muscularis mucosae.
When the stomach is empty the mucosa and submucosa
contract
into thick folds called rugae. As the stomach distends the
rugae
flattens.

9. Blood supply
 Gastric and duodenal blood supply are derived
from the celiac artery and superior mesenteric
artery (SMA) .
 Celiac artery and SMA are derived from the
abdominal aorta.

10. Celiac artery branches to form splenic, left
gastric and common hepatic arteries. Vessels
that branches from these arteries form a dense
anastomotic network that encircles the stomach.
Because of these extensive network gastric
ischaemia is uncommon.

12.  Inferior pancreaticoduodenal branch of the
SMA supplies distal stomach, pylorus and
duodenum.

13.  Stomach and duodenum are innervated by
sympathetic and parasympathetic neurons of
the autonomic nervous system

14.  Reference list
 Kent, M. V. , Ward. R., & Sidney, L.P. (2013), Schaum’s Outline of Human Anatomy and Physiology. (4th ed.)
 Alpers, D. H., & Yamada, T. (2009). Textbook of Gastroenterology. Chichester, West Sussex: Wiley