The gut and its derivatives Flashcards
What is the arterial, venous and lymphatic drainage of the oesophagus?
Arterial: Oesophageal arteries (from the thoracic aorta, bronchial arteries, gastric artery)
Venous: azygos vein, hemiazygos vein and oesophageal branches to the left gastric vein in the abdomen
Lymphatic: posterior mediastinal and left gastric nodes.
What is the innervation of the oesophagus?
Thoracic part:
-Oesophageal plexus, which receives parasympathetic supply from the vagus nerve and sympathetic innervation from the cervical sympathetic trunk
Abdominal part:
-Parasympathetic innervation: arises from the
thoracic oesophagal nervous plexus, while its sympathetic component originates from the fifth to twelfth thoracic spinal nerves T5-T12
Afferent:
Travel via vagus nerves. Can sense osmo-, chemo-, thermo-, and mechanical stimulus
Oesophagus can feel temperature and mechanical pressure but not pain
What are the layers of the stomach?
Layers:
- Mucosa: innermost layer, releases stomach acid
- Submucosa: second layer, contains nerve endings and blood vessels
- Muscles
- Serosa: inner lining of GI tube
Stomach muscle has 3 layers: circular, longitudinal and oblique
What is the internal anatomy of the stomach?
Gastric folds or gastric rugae: ridges of mucosal and submucosal layers, that allow the stomach to expand
Sphincter: a ring of smooth muscle that can relax to allow the passage of some contents
Cardiac sphincter: prevents the acidic contents of the stomach from moving upward into the oesophagus (acid reflux)
Pyloric sphincter: separates the stomach from the small intestine
When sphincters contract = they prevent the movement
When sphincters relax = they allow movement
What is a hiatal hernia?
Stomach protruding through oesophageal hiatus (T10) into the thorax
What are the functions of the different parts of the small intestines?
Duodenum: shortest. is where preparation for absorption through villi begin. Has Brunner’s glands that produce alkaline mucus. Secondarily retroperitoneal
Jejunum: specialized for the absorption of nutrients. Intraperitoneal.
Ileum: absorbs vitamin B12, bile salts, and remaining products of digestion.
Intraperitoneal
What are the different parts of the duodenum?
Superior, descending, horizontal, ascending
What is the blood supply to the gut?
Coeliac Trunk (T12) - supplies foregut
Superior Mesenteric artery (L1) - supplies midgut
Inferior Mesenteric artery (L3) - supplies hindgut
What is the blood supply to the stomach?
Coeliac trunk forms the right and left gastric artery and the splenic artery.
The splenic artery zigzags the stomach and goes to the spleen.
The common hepatic artery forms the gastroduodenal artery. This forms the right gastro-omental artery.
The splenic artery forms the left gastro-omental artery.
The left and right gastro-omental arteries anastomose
The supply to the stomach:
- Right and left Gastro-omental arteries
- Right and left Gastric arteries
What are the branches of the coeliac trunk?
Coeliac trunk forms:
- Gastric arteries
- Splenic artery –> left gastroomental artery
- Commo hepatic artery –> hepatic artery proper and gastroduodenal artery
The gastroduodenal artery forms the right gastroomental artery
What are the branches of the superior mesenteric artery?
- Jejunal and ileal arteries
- Ileocolic artery
- Right colic artery
- Middle colic artery
What does the superior mesenteric artery supply?
Supplies the distal part of the duodenum, all of the jejunum and ileum, the ascending colon, and the proximal 2/3 of the transverse colon
The proximal part of the duodenum is supplied by the gastroduodenal artery and superior pancreaticoduodenal artery (which comes from the gastroduodenal artery)
The distal duodenum is supplied by the inferior pancreaticoduodenal artery from the superior mesenteric artery.
What is the blood supply to the appendix?
Appendicular artery is a branch of ileocolic artery
What are the branches of the inferior mesenteric artery?
- Marginal artery
- Left colic artery
- Sigmoid arteries
What does the inferior mesenteric artery supply?
Supplies distal 1/3 of transverse colon, descending colon, sigmoid colon, proximal rectum