1. Purpose Of The Gut Flashcards
What are all the sections of the alimentary canal from mouth to anus?
Mouth, tongue, pharynx, oesophagus, stomach, duodenum, jejenum, ileum, caecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anus.
Name the accessory organs of the GI tract
Salivary glands, liver, gallbladder, pancreas.
What is the main purpose of the gut?
To digest food into monosaccharides, small peptides and amino acids, fatty acids and glycerol, absorb water and vitamins/minerals. But without absorbing too many toxins, and expelling waste products that were not ingested such as bilirubin and cholesterol.
What areas of the GI tract carry out mechanical disruption?
Mouth/teeth.
Stomach.
What type of mechanical disruption does the upper area of the stomach cause, and what does the lower area cause?
Upper area - basal tone (slow sustained contractions).
Lower area - powerful peristaltic contractions to grind food.
What does the stomach contain to help mechanical disruption?
Inner oblique layer of muscle
What sphincter controls the movement of chyme from the stomach to the duodenum?
Pyloric sphincter.
What 2 areas of the GI tract act as storage facilities and how?
Stomach - due to rugae and receptive relaxation.
Colon - acts as temporary storage with contents only evacuated several times a day.
What enzymes are present in saliva?
Amylase and lipase
What chemicals are present in the stomach for digestion?
Acid and pepsin
What chemicals are present in the duodenum and jejunum for digestion?
Bile and protease, lipase, amylase (from exocrine pancreas)
What are the main defences in the GI tract against pathogens?
Saliva.
HCl.
Kupffer cells in the liver.
Peyers patches for immune surveillance.
By what 4 mechanisms does the GI tract move food along?
Peristalsis.
Segmentation.
Haustral shuttling.
Mass movements.
What 3 features/structures of the GI tract aid absorption by increasing surface area?
Length of the gut.
Folds.
Villi/microvilli.
Where is most water absorbed in the GI tract?
Ileum
