GI Flashcards
Purpose of the gut (8)
Port of entry for food Mechanically disrupt food Temporary food storage Chemically digest food Kill pathogens on food Move food along tract Absorb nutrients from food Egest waste products
Sphincters of the gut (6)
Upper oesophageal Lower oesophageal Pyloric Illeocaecal Internal/External anal
Which is longer the jejunum or the ileum?
Ileum (350cm) Jejunum (250cm)
Areas of mechanical disruption (2)
Mouth (teeth)
Stomach (antrum)
Sections of the stomach (5)
Cardia Fundus Body Pyloric Antrum Pylorus
Muscle layers of the stomach, from outside to inside (3)
Longitudinal
Circular
Oblique
How does the stomach allow for the storage of food (2)
Rugae of the stomach allow for its expansion
Receptive relaxation means intraluminal pressure does not increase when food is received
Areas of temporary food storage (2)
Stomach
Colon
GI Defences against pathogens (4)
Saliva
HCl
Kupffer cells (liver)
Peyer’s patches (terminal ileum)
What are Peyer’s patches?
Lympathtic tissue nodules that are not surrounded in a fibrous capsule. Recognise pathogenic antigens, which are presented to T and B Lymphocytes, resulting n the production of cytotoxic T cells
Types of movement (4)
Peristalsis
Segmentation
Haustral shuttling
Mass movements
What is the mixture of muscle in the GI tract? (2)
Some skeletal
Mostly smooth muscle
Structural features that aid absorption (3)
Length
Folds(plica circularis in the small bowel, haustra in the colon)
Villi/microvilli
Mass movement (4)
Colon temporary storage sight
Rectum normally empty
Internal/external anal sphincter
Gastrocolic reflex
Mouth fuction (3)
Mechanical disruption of food Initial digestive enzymes released Infection control (lysozymes, IgA, IgG)
Oesophagus function (3)
Fast transport of bolus to stomach
UOS prevents air entering GI tract
LOS prevents acid reflux
Stomach function (6)
Storage Physical breakdown Chemical breakdown Digestion starts Infection (HCl) Secreteintrinsic factor (Vit B12)
Duodenum function
Site of neutralisation of chyme (HCO3-)
Digestion (pancreatic enzymes and bile, sphincter of Oddi)
Jejunum/Ileum function (5)
Final digestion Nutrient absorption (mainly jejunum) Water/electrolyte absorption ( mainly ileum) Bile recirculation (ileum) B12 absorption (terminal ileum)
Colon function (3)
Final water absorption
Final electrolyte absorption
Storage
Rectum function (1)
Defaecation
Kupffer cells
Specialised macrophages lining the walls of the sinusoids in the liver
Peristalsis
Adjacent segments of the alimentary tract alternately contract and relax, which moves food along the tract distally
Segementation
Nonadjacent segments of the alimentary tract contract and relax, moving food forwards and then backwards, mixing the food and slowly propelling it distally
