GI System Flashcards
What are the 6 functional divisions of the GI tract?
- Ingestion
- Secretion
- Mixing and propulsion
- Digestion
- Absorption
- Defecation
Why can most food not be absorbed in the form we eat?
Physically too big
Chemically too complex
This enzyme breaks down carbohydrates while chewing
Salivary amylase
This enzyme breaks down triglycerides while chewing
Lingual lipase
Series of contractions that move bolus down GI tract
Peristalsis
Describe the muscle movements involved in peristalsis
Circular muscles behind bolus contract
Circular muscles in ahead of bolus relax
Longitudinal muscles contract (shortens the length of the tube)
Why is HCL in the stomach important?
> kills most microorganisms
> denatures proteins
> break down plant cell walls
>activates pepsinogen to form pepsin!!!!!*
> promotes flow of bile and pancreatic jooses
What does pepsin do
Breaks down proteins in the stomach
What does gastric lipase do and what is its required pH
Breaks down triglycerides; pH required is 5-6
Most materials are not absorbed in the stomach. Why?
Mucus lining
Cell structure
Limited time chyme spends in stomach
Although most materials are not absorbed in the stomach, what are two exceptions?
Alcahooool and aspirin
Name the three parts of the small intestine in order.
Duodenum
Jejunum
Ileum
How does the duodenum not disintegrate from the highly acidic chyme that is being pushed through it
It produces secretions to protect it from acid and enzymes in chyme
________ duct empties into duodenum
Pancreatic
Arrival of chyme into duodenum stimulates _______ secretions
Pancreatic
What’s the recipe for dat gud gud pancreatic joose?
Amylase, lipase, nucleases & proteases/peptidases
What does dat gud gud pancreatic joose do?
Helps digestion; raises pH of chyme
:)
True or false: this isn’t so bad and it all makes sense when you think about it
True :)
What 4 things do hepatocytes do?
- Metabolize carbs, lipids, proteins
- Process drugs and hormones
- Excrete bilirubin (makes your poops brown)
- Makes bile salts
Where is bile produced and what does it do?
Liver; emulsifies lipid droplets to make them smaller and easier to absorb
Where is bile stored?
Gall bladder
90% of nutrient absorption occurs where
Small intestine
Structure on intestinal cells where nutrients are absorbed into the blood
Villi
Starches must be broken down into ________ in order to enter bloodstream
Monosaccharides
Glucose and galactose enter intestinal cells via secondary ______ transport
Fructose enters intestinal cells by __________ diffusion
Active
Facilitated
Peptides must be broken down into _______ to be absorbed
Amino acids
What happens when lipids combine with bile salts
They become emulsified
What enzyme is needed to break down emulsified lipids into fatty acids
Pancreatic lipase
Which part of the GI tract absorbs hella water and makes you gassy
Large intestine
B and K vitamins are absorbed where
Large intestine
