Digestion Flashcards
What is another name for the digestive system?
The Gastrointestinal Tract
What is the name of the food and enzyme mixture?
Chyme
How long is the gastrointestinal tract?
About 8 m long
What is the length of the mouth oesophagus and stomach?
150 cm
All of these are in the small intestine.
How long are they?
Duodenum
Jejunum
Illeum
Duodenum- 25 cm
Jejunum- 260 cm
Ileum - 260 cm
Name the 3 parts of the small intestine
Duodenum
Jejunum
Illeum
Name 7 parts of the large intestine
Caecum
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
AnusWhat is the roles of the oral cavity and oesophagus?
Digestion of carbs
No absorption
Chewing and swallowing
What is the roles of the stomach?
Digestion of proteins and fats
Absorption of lipid soluble substances
Peristaltic mixing and propulsion
What are the roles of the small intestine?
Digestion of polypetides,carbs,fats,nucleic acids
Wide range of adsoption
Mixing and propulsion
What are the roles of the large intestine?
No digestion
Absorption of ions, minerals, vitamins, water
What are sphincters?
These guard different sections and control movement through the digestive tract
What are the 5 main parts of the stomach?
Fundus Body Antrum Rougae Pylorus
What is the role of the rugae in the stomach?
Surface foldings increase surface area
Is the small intestine heavily muscular?
YES
What are the 4 layers of the gastrointestinal tract?
Mucose
Submucosa
Smooth Muscle
Serosa
What is the role of the mucosa?
Includes transporting epithelial cells, connective tissue and nerve fibres and blood vessels
What does the submuscosa contain?
Submuscosal plexis
Name the outer layer of the GI
Serosa
Name the 3 glands that make up the salivary glands
Parotid glands
Submandibular glands
Sublingual gland
What is the Sphincter of Oddi?
smooth muscle that surrounds the end portion of the common bile duct and pancreatic duct.
What are the role of the pancreas?
Releases enzymes and secretes hormones
Which cells in the pancreases secret digestive enzymes?
Acinar cells
What do duct cells in the pancreas secrete?
NaHCO3
What do the islet cells of the pancreases secrete?
Hormones
Which cells form the exocrine portion of the pancreas?
Pancreatic acini
Name 4 parts of the liver
Hepatic Artery
Hepatic portal Vein
Common bile duct
Gall bladder
What is the role of the hepatic Artery?
Brings oxygenated blood from the tissues to the liver
What is the role of the hepatic portal vein
Carries blood from the GI and Hb from the spleen
What is the role of the common bile duct?
Carries bile from the gall bladder to the intestine
What is the role of the gall bladder?
Stores and concentrates bile
Describe the structure of the veins
Hepatocytes arranged in lobules around a central vein
Triads of portal vein, bile duct and hepatic artery
Describe how bile is made
Hepatocytes produce bile which is transported to the bile canaliculi and to the bile duct
H2O and bicarbonate are added by duct epithelial cells
What happens to the bile once it has been made?
Secreted into the duodenum
Passed to gall bladder, concentrated up to 15 times and stored at a max volume of 60 mls
Name the 2 types of contraction
Phasic contraction
Tonic contractions
Describe phasic contractions
intestinal cells of Cajal generate slow wave potentials to produce cyclic relaxation contraction
Describe tonic contractions
Long term contractions
What is the role of hte migrating motor complex?
Contractions passing slowly from segment to segment
How long is a peristalsis wave?
2-25cm
What are the parts of the enteric nervous system and their roles?
Submucosal plexus- contains sensory neurons that receive signals from the lumen and control secretion
Myenteric plexus- controls motility
What are 3 types of reflexes?
Short
long
cephalic
