Gastrointestinal System

salivary amylase breaks down starch into di and tri- saccharides

pancreatic a-amylase breaks down remaining complex CHO

they convert disaccharides to monosaccharides

absorbed into the bloodstream by facilitated diffusion and cotransport mechanisms

co-linked with Na transport

• does not require ATP 
• will not occur against the conc. gradient

more then one molecule can move through the membrane; can occur against a conc. gradient - ATP required

lingual lipase and pancreatic lipase

bile salts improve digestion by emulsifying the lipid into tiny droplets

micelles are tiny droplets of emulsified lipids (fatty acids + monoglycerides)

chylomicrons are lipoprotein particles that consist of triglycerides, phospholipids, cholesterol and proteins

they transport dietary lipids from the intestines to other locations in the body

only occurs after food has been processed

• trypsin 
• chymotrypsin
• elastase
• carboxypeptidase

inactive process occurring along an osmotic gradient

continuously absorb nutrients and ions

absorbed by diffusion, co-transport or active transport

active transport

absorbed from micelles with dietary lipids

absorbed by diffusion across epithelium

absorbed by active transport when bound to intrinsic factor

produced by parietal cells of stomach

• rate of proliferation of epithelial stem cells declines 
• smooth muscle tone decreases 
• cumulative damage to GIT 
• cancer rates increase 
• dehydration