S1 - Purpose Of The GUT Flashcards
What is digestion ?
Makes food into a sterile, neutral and isotonic solution of small sugars, amino acids and small peptides and this is now ready for absorption and excretion.
What does the mouth and oesophagus during digestion ?
Mastication
Release saliva - protects mouth and lubricates for mastication and swallowing
Swallowing - formation of bolus and rapid oesophageal transport to stomach
What does the stomach do during digestion ?
Storage Initial disruption - peristaltic contractions - secretes acid and proteolytic enzymes - creating chyme Delivers chyme slowly inton the duodenum Infection control (HCL)
What does the duodenum do during digestion ?
Dilution and neutralisation of Chyme (HCO3)
- alkali(bile) added from liver and pancreas
What does the small intestine do during digestion ?
Absorption of nutrients and electrolytes via epithelial cells
Absorbs majority of water
Bile recirculation
What does the large intestine do during digestion ?
Final absorption of water (0.15L) and electrolytes
Farces form and accumulate in the descending and sigmoid colon
What does the rectum do during digestion ?
Faeces propelled periodically into rectum
Controlled relaxation of sphincters and expulsion of faeces
What is the purpose of the gut ?
Port of entry for food Mechanically disrupt food Store food Digest food chemically Kill pathogens Move food along tracts Absorb nutrients Eliminate residual waste material
What are the enzymes released from Saliva ?
Amylase (starch) and Lipase (Fats)
Stomach - acid and pepsin (protein)
Duodenum and jejunum - bile and exocrine pancreas
What is the peritoneal cavity ?
Space between parietal and visceral peritoneum
Cavity is empty apart from the fluid it secretes
The entire abdominal wall is parietal and the small intestine is visceral
