Gastro & Hepatic Systems Flashcards
What is function of mouth?
- To prepare food for swallowing
- Mixes food with amylase in the saliva to break down starch into sugars.
What are salivary glands called?
Submandibular
Parotid
Sublingual
How much saliva is produced daily in adults?
500ml
What is oesophagus wall made of?
Mucosa,
submucosa
muscularis mucosa
What is GOJ?
Gastro-oesphageal junction
physiological barrier which reduces reflux of gastric contents.
What is at base of oesophagus?
Intrinsic lower oesophageal sphincter
What causes food to move down oesophagus?
Peristalsis
What is peristalsis regulated by?
Smooth muscles controlled by:
Enteric Nervous System
Peptide Hormones
Inherent timing of monocytes
What does the stomach secrete to aid digestion?
Hydrochloric acid
Lipase
Pepsin
What regulates stomach fluid secretions?
Central and enteric nervous system
Neuroendocrine cell networks
How does mechanics of stomach work?
Very coordinated antropyloroduodenal contractions to titrate solid food
What is titration of food?
Breaking it down
What is purpose of gastric antrum?
Sieves liquid chyme through remaining solid matter in stomach and delivers slow rate of gastric contents into the duodenum.
What is function of small intestine?
To absorb water, electrolytes and nutrients
What is approximate length of duodenum?
30cm
What is length of jejunum
2.5metres
What is length of ileum?
4 metres
Where does common bile duct enter small intestine?
Duodenum - about half way down.
What is chyme?
Acidy pulpy fluid that passes from stomach to small intestine
What happens as food passes from stomach to small intestine?
Chyme passes into small intestine which stimulates release of hormones secretin & CCK (cholecystokinin).
The stimulates release of bicarbonate and pancreatic enzymes and causes gallbladder to release bile.
Where is CCK produced?
Cholecystokinin - produced in I cells in lining of duodenum
What foods are broken down into different things in the small intestine?
Proteins/peptides - amino acids
Lips - fatty acids and glycerol
Triglycerides - free fatty acids and monoglycerides
Carbs - oligosaccharides
What is water uptake driven by in s.intestine?
Absorption of Na and K
How much fluid passes through small bowel each day?
9litres. Mixture of water and secretions
What is function of large bowel?
- Propulsion of colonic contents towards rectum for expulsion
- Absorption of water and electrolytes from remaining chyme
- Absorption of short-chain fatty acids produced from microbiota
- Defacation
What is function of short chain fatty acids the large bowel?
To keep microbiota of gut wall healthy
To help with remaining absorption of sodium
How long is typical transit of chyme in adult?
12-30 hours
What does wall of colon do?
Has role in production of vit k, vit b7 and B3
What does the stomach absorb?
Alcohol
What does duodenum absorb?
Cl, SO4, Iron, calcium, magnesium
What does Jejunum/ileum absorb?
glucose vit c thiamin ribolfavin folic acid prtein fat cholesterol Vit A & D
What does colon absorb?
Na
K
Vit K
H20
What is peristalsis?
Contraction and relaxation above and below a bolus of food to push food through gut
How does peristalsis work?
Pre bolus: circular contracts
longitudinal muscle relaxes,
Post bolus: circular muscle relaxes
longitudinal muscle contracts
How many lobes are in the liver?
2 main lobes with 4 lobes within that, and 8 segments altogether
which ligament divides the liver?
falciform ligament
How much weight does the liver contribute in adults and infants?
2.5% in adults
5% in infants