DIGESTION Flashcards
4 stages of processing nutirents
ingestion
digestion
absorption
eleimination
ingestion
eating
digestion
sequential process of breaking down into smaller pieces/parts at the end of digestion, left with small absorbable molecules.
absorption
cells take up amino acids, sugars, fatty acids
elimination
undigested material passes out of digestive system
Intracellular digestion
particles taken in by phagocytosis or pinocytosis (small organisms)
extracellular digestion
occurs in specialized compartments that are contiguous with outside of the body.
ex. gizzard, Gastric ceca.
first 10 seconds
oral cavity, pharynx and esophagus food triggers saliva mucin coats/protects oral cavity antibacterial agents peristalisis-waves of coordinated muscular contractions move the food bolus to the stomach in an involuntary fashion
Stomach 2-6 hours
stores food and begins the chemical digestive process
protein digestion
can hold about 2L of food
contents are mixed with gastric juice about every 30 sec. to digest food.
both exit and entry closed off by sphincters
Ulcers
when the protection beaks down in the lining of the stomach
digestion
life in the proximal small intestine
duodenum
jejunum
lleum
duodenum (25-30cm)
most of enzymatic hydrolysis and nutrient absorption is here
pH~6
jejunum (2.5m)
contributes to the nutrient and water absorption
pH~7-8
lleum (2-4m)
primarily absorbs vitamin B12, bile salts and anything the jejunum missed.
pH~7-8
Villi
large number of folds in the lining of the intestine
epithelial cells have microvilli
nutrients absorbed goes straight to the circulatory system
