Week 1.2 - General Structure of Alimentary Canal Flashcards
What is the length from the oesophagus to the rectum?
8 metres length
What is the general structural organisation throughout the GI tube wall?
- mucosa
- submucosa
- muscularis externa
- adventita/serosa
What are the 3 layers of the mucosa?
- innermost epithelium
- lamina propria
- muscularis mucosae
What is the lamina propria?
loose connective tissue with glands, blood and lymph
What is the muscularis mucosae?
thin, smooth muscle layer attached to lamina propria for motility
What is the submucosa made of?
thick, regular connective tissue to support mucosa
What does the submucosa contain?
- most of the blood vessels and neurons are here to support all layers.
- also glands in some parts
What is the purpose of the submucosal glands and where are they found?
oesophagus for lubrication
duodenum for neutralising acidity from stomach products
Which neurons are found in the submucosa?
submucosal plexus. mainly parasympathetic.
What is the submucosal plexus also known as?
Meissner’s Plexus
What are the 2 sets of nerve plexus in the GI system? What are the called colectively?
Enteric Nervous System.
Submucosal plexus and myenteric nerve plexus
What are the 2 parts of the muscularis externa?
inner circular msucle layer for constricting lumen
outer longitudinal muscle layer for shortening length
What nerve plexus is found in the muscularis externa and where?
between the circular muscle and the longitudinal muscle, the myenteric plexus is found
What is the serosa vs the adventita?
adventita is the outer layer of GI tract outside the peritoneal cavity - attaches oesophagus and rectum to surrounding surfaces
serosa is outer layer of GI tract inside the peritoneal cavity - surrounds stomach, SI and LI
What is the peritoneum?
serous membrane forming lining of abdominal cavity
Which type of epithelium are found in the GI tract?
simple cuboidal for digestion+absorption and acid protection in stomach, SI and LI
stratified squamous for protection from friction of large products in eosophagus and rectum
What is the parasympathetic control of alimentary function?
vagus from 10th cranial, except for salivary nerve (7th) and glossopharyngeal nerve (9th)
stimulatory effect - motility and secretion
What is the sympathetic control of alimentary function?
mainly splanchnic except for salivary.
inhibitory effect.. except salivary - increases salivation but decreases motility and secretion
What veins drain the stomach and pancreas?
stomach - gastric vein
pancreas - splenic vein
