GI Tract and Motility Flashcards
Accessory structures of the GI tract?
Pancreas
Salivary Gland
Liver and Gall Bladder
What muscle is mainly involved in the GI tract?
Smooth Muscle
Describe digestion of Carbohydrates?
Polysaccharides (Eg: Starch and Glycogen) go to Monosaccharides (Glucose, Galactose, Fructose)
Mediated by Amylases
Describe protein digestion?
Protein goes to amino acids, dipeptides and tripeptides
Mediated by proteases
Describe fat digestion?
Fat goes to Monoglyceride and Free Fatty Acids
Mediated by Lipase
What two liquids are the products of digestion transferred to?
Blood and Lymph
Protein and Carbohydrates go to blood
Fats go to lymph
What are the four basic processes of digestion?
Motility
Secretion
Digestion
Absorption
Describe the digestive tract wall?
How to remember this?
Mucosa: Epithelial Lamina Propria Muscularis Mucosae Submucosa Muscularis Externa Serosa
Mate: Every little person might make some meaty eaty sausages
Mum, every little person might make some meaty eaty sasuage
Mucosa - Epithelium, lamina propria, musclaris mucosa
Submucosa
Muscularis Externia
Serosa
What happens if circle muscle contracts?
Lumen becomes narrower and longer
What happens in longitudinal muscle contracts?
Intestine becomes shorter and fatter
What happens when the Muscularis Mucosa contacts?
Changes the absorptive and secretory area of the mucosa
How does electrical signals pass through smooth muscle?
Through gap junctions. There is a functional synctium which allows hundreds of cells to depolarise and contract at the same time
What drives slow wave activity?
Interstitial Cells of Cajal
In smooth muscle slow wave, what mediates upstroke? What mediates downstroke?
Voltage activated Ca2+ channels
Voltage activated K+ channels
What parts of the GI tract are skeletal muscle?
Mouth
Pharynx
Upper Oesophagus
External Anal Sphincter
Name all the sphincters?
Upper Oesophageal Sphincter Lower Oesophageal Sphincter Pyloric Sphincter Ileocaecal Sphincter Internal Anal Sphincter External Anal Sphincter
Sphincter of Oddi
Where is the swallowing centre?
medulla