GI Flashcards
What is the name of the muscular wave-like movements that move food along the GI tract
Peristalsis
What are the functions of tight junctions?
Hold cells together They block the movement of molecules and ions between the cells They block the movement of integral proteins between the apical and basolateral surfaces
Give the 4 main layers of the GI wall
Mucosa Submucosa Muscularis externa Serosa
GI wall: give the name of the loose connective tissue just below the epithelium through which pass vessels, nerves and lymph vessels
Lamina propria
Give the 3 layers of the mucosa
Epithelium Lamina propria Muscularis mucosa (thin layer of smooth muscle)
Contraction of which muscle in the submucosa is responsible for the moving and mixing of luminal contents?
Muscularis externa
The muscularis external has 2 muscles except in one organ where it has 3. Which organ is this?
The stomach
What are the two plexuses found in the GI wall?
The submucosal plexus (superficial) and the myenteric plexus
What 3 features are present on the surface of the small intestine to increase the SA?
Circular folds (mucosa & submucosa) Villi Micro villi
Where in the small intestine do new epithelial cells arise from?
New cells arise from division of the cells at the base of the villi. They differentiate as they move up the villi and replace those that die and are discharged into the lumen
Roughly, how many epithelial cells are replaced each day? a) 5 million b) 5 billion c) 17 billion d)23 billion
c) 17 billion
Roughly, how many epithelial cells are replaced each day? a) 5 million b) 5 billion c) 17 billion d)23 billion
c) 17 billion
At the centre of each intestinal villus, is a blind ended lymphatic vessel. What is it called?
Lacteal
What type of epithelium is in the small intestine?
Simple columnar with microvilli
What is the name of the regions of immune tissue which can be found in the small intestine?
Peter’s factors - these secrete factors that alter intestinal motility and kill microorganisms
Give the 4 main functions of saliva
Moistens and lubricates food Initiates small amounts of digestion of polysaccharides by amylase Dissolves small amounts of food which facilitates taste Kills bacteria
What are the functions of the stomach?
Store, dissolve and partially digest the macromolecules in food. Regulate the rate at which food is released into the duodenum.
Give the main food components which are not broken down by the stomach acid
Polysaccharides and fat