(structure of the digestive tract and digestive processes) 5 main structures
(structure of the digestive tract and digestive processes) what are 3 accessory organs?
Oral cavity) Where does digestion begin?
in the mouth
Oral cavity) What provides mechanical digestion in the mouth?
Oral cavity) what are the 2 salivary enzymes?
Oral cavity) what does salivary amylase digest?
Oral cavity) What does lingual lipase digest?
Oral cavity) What type of digestion does salivary enzymes perform?
Oral cavity) what are the 3 salivary glands?
esophagus and swallowing) What is food called when it is mixed and chewed with saliva?
esophagus and swallowing) what are the 3 phases of swallowing?
esophagus and swallowing) Voluntary phase:
food is voluntarily swallowed and pushed backwards into the pharynx
esophagus and swallowing) Pharyngeal phase:
involuntary contractions move bolus into esophagus
esophagus and swallowing) Esophageal phase
involuntary contractions move bolus through esophagus, through the lower esophageal sphincter into the stomach
stomach) 4 main regions
-antrum or distal pyloric region
stomach) functions: (2)
-grinds and mixes foods in gastric region to form chyme
-provides strong peristalsis for gastric emptying
stomach) Where are cardiac glands?
stomach) where are oxyntic glands?
stomach)where are pyloric glands?
stomach) what are the 4 types of cells in the glands?
(gastric juice) what 2 things does HCl do?
-cleaves pepsinogen into pepsin
(gastric juice) what does pepsin do?
breaks down proteins into peptides
(gastric juice) what do enzymes form?
(gastric juice) what does gastric lipase do?
cleaves fatty acids from triacyleglycerols
(gastric juice) what does pepsinogen do?
zymogen precursor to pepsin
(gastric juice) what do mucus-glycolipids/glycoproteins do? (2)
-protect lining of stomach from HCl
how much absorption is there at stomach?
- *water, meds, alcohol, some minerals
stomach) what 2 things in stomach perform protein hydrolysis?
stomach)what 2 things perform Triacylglycerol breakdown: (2)
stomach)why is starch breakdown halted here?
low pH inactivates salivary amylase
stomach) what happens if the mucus that lines the stomach breaks down>
peptic ulcer can ensue
stomach) what 3 things can breakdown the mucus lining of stomach?
GERD) why does heartburn occur?
when HCl refluxes back into the esophagus bc of misalignments of stomach or excessive HCl
GERD) what does treatment focuses on.
blocks HCl production
small intestines) 3 things tht compose it
small intestines) where does most digestion and absorption occur?
small intestines) what does the pancreas secrete? (3)
-secretes bicarb, electrolytes, & 13 different digestive enzymes
small intestines) what does the liver produce and secrete/
bile for the emulsification of fats
small intestines) What does gallbladder store and secretes?
- *stores bile for high fat meals
small intestines) where do pancreas,liver, gallbaldder secrete their products?
structural aspects of small intestines) Lumen
the opening of the intestines which chyme passes through
structural aspects of small intestines) folds of kerckring
circular folds of mucosa that protude into the lumen
structural aspects of small intestines) Villi
structural aspects of small intestines) microvilli
hair-like extensions of the enterocytes plasma membrane
Colon-large intestines) what does its proximal colonic epithelia absorb?
-Na, Cl, and H2O
Colon-large intestines) what happens to materials in here?
they get dehydrated
constipation) what is infrequent defecation?
less than 3 times/ week
Gastric regulation and fight or flight response) what 2 thigns happen during sympathetic nervous system?
-stress hormones inhibit gastrin
-tends to inhibit gastric secretions, peristalsis, digestion
Gastric regulation and fight or flight response) what two things happen during parasympathetic nervous system?
-increase gastric secretions
-promote good digestion
intestinal bacteria(microflora), pre and probiotics, and disease) fermentation:
breakdown of CHO and protein anaerobically
intestinal bacteria(microflora), pre and probiotics, and disease) Probiotics
foods containing live bacterial cultures
intestinal bacteria(microflora), pre and probiotics, and disease) Prebiotics:
food ingredients that promote bacterial growth
intestinal bacteria(microflora), pre and probiotics, and disease) what are probiotics thought to do? (5)
-prevent colonization by pathogens
-lower pH of the colon
-transform/promote excretion of toxic substances
-enhance fecal bulk
IBS) what is the most common functional bowel disorder?
IBS) why is IBS called a functional GI disorder?
it is a problem caused by changes in how the GI tract works
IBS) does the GI tract become damaged?
IBD) what is IBD?
conditions with chronic or recurring immune response and inflammation of the GI tract
IBD) what is the cause for IBD?
IBD) Crohn's disease:
causes inflammation, swelling, and irritation of any part of the GI tract
IBD) Ulcerative colitis:
causes inflammation and ulcers in the inner lining of the large intestine
Do probiotics survive the digestive tract?
yes, specific strains of bacteria can survive digestion to affect the bacterial diversity in the colon
does fermented dairy help with constipation/
yes, yogurt has beneficial effect on constipation
Does fermented dairy help with micro/macro nutrient aborption?
no, it does not seem to increase absorption except in lactose intolerance
can fermented dairy help with IBS and IBD?
yes, probiotic and synbiotic supplementation has beneficial effect on IBS and IBD