1.1 Purpose Of The Gut Flashcards
Name some accessory organs of the GI tract
Salivary glands
Liver
Gallbladder
Pancreas
What are some examples of waste products that the gut needs to expel?
Bilirubin
Cholesterol
What are the roles of the gut?
Port of entry Mechanically disrupts food Temporarily store food Chemically digest food Kill pathogens in food Move food along tract Absorb nutrients Eliminate residual waste material
Where does mechanical disruption occur?
Mouth/teeth
Stomach
What does muscle in the upper area of the stomach do?
Creates basal tone by slow, sustained contractions
What does the muscle of the lower stomach do?
Powerful peristaltic contractions that grind the food
Why are the contractions of the lower stomach more powerful than the upper stomach?
Has a thicker muscle layer
An additional inner oblique layer of muscle of the muscularis externa
How is the stomach a storage facility?
Has temporary folds called rugae
Why is it important that receptive relaxation occurs in the stomach?
So intraluminal pressures dont increase
Where in the GI tract are there storage facilities?
Stomach
Colon
How is the colon evacuated?
Through mass movement
What enzymes are present in saliva?
Amylase - starch
Lipase - fats
What in the stomach allows chemical digestion?
Acid
Pepsin - protein
What allows chemical digestion in the duodenum/jejunum?
Bile
Exocrine pancreas
Describe some of the defences of the GI tract against bacteria
Saliva
HCl
Kupffer cells in the liver
Peyers patches for immune surveillance
What four types of movement are there in the GI tract?
Peristalsis
Segmentation
Haustral shuttling
Mass movements
What structural features of the gut aid absorption?
Length of gut
Folds
Villi and microvilli
What are the functions of the mouth?
Physical breakdown of food
Initial digestive enzymes released
Infection control
What are the functions of the oesophagus?
Rapid transport of bolus to stomach through thorax
UOS prevents air from entering the GI tract
LOS helps prevent reflux into oesophagus
What are the functions of the stomach?
Storage facility Product chyme - physical and chemical breakdown, digestion started Infection control - HCl Secrete IF from parietal calls
What are the functions of the duodenum?
Neutralisation of chyme
Where does the majority of nutrient absorption occur?
Jejunum
Where does the majority of water/electrolyte absorption occur?
Mainly ileum
Where does bile recirculating occur?
Ileum
Where does B12 absorption occur?
Terminal ileum
What are the functions of the large bowel?
Final water absorption
Final electrolyte absorption
What is the function of the rectum/anus?
Defaecation
