Ch. 1. Intake: GI Digestion, Absorption, & Excretion of Nutrients Flashcards
A hormone that stimulates the pancreas to secrete water and bicarbonate and inhibit gastrin secretion
Secretin
The semifluid, gruel-like material produced by the gastric digestion of food
Chyme
Non-digestible food ingredients that have a specific stimulatory effect on GIT bacteria
Prebiotic
Large cells that are scattered along the walls of the stomach and secrete hydrochloric acid in gastric juice
Parietal cells
Hormone that stimulates the pancreas to secrete enzymes, stimulate gallbladder contraction, slows gastric emptying, stimulates colonic activity, and may regulate appetite
Cholecystokinin (CCK)
The movement of particles by a carrier protein across cell membranes that require energy (ATP)
Active transport
Polypeptide gastrointestinal hormone that promotes gastric emptying and intestinal motility
Motilin
A complex of primarily free fatty acids, monoglycerides, and bile salts that allows lipids to be absorbed into intestinal mucosal cells
Micelle
An enzyme secreted by the pancreas that catalyzes the hydrolysis of starch
Amylase
Minute cylindrical processes that are found on the surface of the intestinal cells and greatly increase their absorptive surface area
Microvilli
An enzyme in pancreatic juice that hydrolyzes the ester linkages between fatty acids and glycerol
Pancreatic lipase
Movement by which the alimentary canal propels its contents
Peristalsis
Microvilli that greatly increase the surface area of intestinal mucosal cells
Brush-border
Numerous finger-like projections that cover the surface of the small intestine mucosa
Villi
A polypeptide hormone secreted from the stomach, small intestine, and pancreas that tends to inhibit other gastrointestinal secretions and motility
Somatostatin
Hormone that is produced by the antral mucosa of the stomach and stimulates gastric secretions and motility
Gastrin
A protease active only in the acid environment of the stomach serves to change the shape and size of some proteins in a meal
Pepsin
The process of fermenting and absorbing end products of dietary carbohydrates, fiber, and amino acids in the large intestine
Colonic salvage
Food or concentrate of living organisms that contributes to a healthy microbial environment and suppresses potential harmful microbes
Probiotic
Movement of particles via a transport or carrier protein
Facilitated diffusion
About what percentage of the mixed American diet is digested and absorbed?
90-97%
The mixing of chyme and digestive secretion is
Segmentation
The pH of the lumen is too low, gastrin secretion is
Inhibited
What inhibits gastrin secretion?
1) Impulse from vagus nerve: smell or sight of food
2) Distention of antrum after eating
3) Presence of secretagogues in antrum: partial digested proteins, fermented alcohol drinks, caffeine, or food extracts (bouillon)
Which of the following enzymes is secreted by the stomach? Motilin CCK Gastrin Secretin
Gastrin
Bile is important for the digestion of
Fats
What are the 3 proteolytic enzymes?
Trypsin, Chymotrypsin, Pepsin
Where are most nutrients absorbed?
Small intestine
Carbohydrate digestion begins in the
Mouth
What are some good sources of Prebiotics?
Veg: Onions, garlic, asparagus
Fruit: Bananas, apples, stone fruits, mangos
Grains, legumes, chicory, Jerusalem artichokes, soybeans, and wheat bran
What are some good sources of Probiotics?
Fermented food products such as yogurt, miso, sauerkraut, kimchi, and kefir
Approximately what volume of colon contents are bacteria?
35-50%
Where is bile stored?
The gallbladder
What is the current recommendation for fiber consumption?
14g per 1000kcal
Where does bacterial fermentation occur?
The large intestine
Incretin hormones act to
Lower blood sugar
Enzymatic fat digestion begins in the
Mouth
