Intro , Purpose Of Gut Flashcards
What is the purpose of the GI system ?
- entry for food
- mechanically disrupt food
- temporarily store
- chemically digest
- kill pathogens
- move food
- absorb water and nutrients
- expel waste product
Name the different parts of the GI tract
Mouth,Oesophagus,Stomach,Duodenum,Jejunum,Ileum,Caecum,Ascending,Transverse,Descending,Sigmoid,Rectum,Anal canal
What are the areas involved in mechanical disruption ?
Mouth
Stomach
What are the storage areas of the GI ?
Stomach :distend (rugae) and relax
Colon (transverse and descending)
State the areas involved in chemical digestion and how ?
Saliva : amylase , lipase
Stomach : acids , pepsin
Duodenum/jejunum : Bile, exocrine section from pancreas
How does the GI system prevent entry of pathogens ?
Epithelium Saliva has IgA Acid Kupffer cells from liver Peyers patches : lymphoid follicles in mucosa in intestines
What structural features of the gut aid absorption ?
Length
Folds (rugae and plicae circulares )
Villi/microvilli
What are the broad functions of the mouth ?
Physical disruption, digestion,infection control
What are the broad functions of oesophagus ?
Rapid transport of bolus to stomach,
Upper sphincter prevents air in GI
Lower sphincter prevents reflux
What are the broad functions of the stomach ?
Storage, infection control
Produce chyme : physical ,chemical breakdown,digestion
Secretion of Intrinsic Factor
What are the broad functions of the duodenum ?
Neutralisation and osmotic stabilisation of chyme : HCO3 secretions
Digestion : pancreatic secretion, bile
What are the broad functions of the Jejunum ?
Final digestion
Nutrient absorption
What are the broad function of the ileum ?
Final digestion
Water and electrolytes absorption
B12 absorption
Bile recirculating
What are the broad functions of the large bowel ?
Water reabsorption ( Aquaporines , not paracellularly due to tight junction ) Electrolyte reabsorption
What is the peritoneal cavity ?
Space between parietal and visceral peritoneum
What are the embryonic origins of the peritoneal layers ?
Parietal : somatic
Visceral : splanchnic
What is the mesentery ?
Double fold of peritoneum that supports the intra peritoneal viscera and attaches it to the posterior abdo wall and allows conduit for vessels
What lies behind the root of the mesentery ?
Peritoneum
What are peritoneal recesses ? Name 4
Areas of peritoneal cavity where pathological fluids can collect or channels that allow fluid to move
- Vesicouterine pouch
- Rectouterine pouch (of Douglas )
- Rectovesical pouch
- Paracolic gutters
What is the greater omentum ?
Double folds of peritoneum (attached to stomach ) connecting structures together or to the abdominal wall and covering the bowels
What is the lesser omentum ?
Double layer of peritoneum extending from lesser curvature of stomach to liver
What are the layers of the abdominal wall ?
Skin Superficial fascia Investing fascia Abdominal muscles : external oblique, internal oblique , transversus abdominis , rectus abdominis Transversalis fascia Peritoneum
