Digestion Flashcards
What happens in Ingestion
This is when food enters your mouth
What occurs in digestion
Hydrolysis of large insoluble molecules into small soluble ones, using enzymes
What happens in absorption
Molecules pass through the epithelium of the small intestine to enter the blood or lacteal
What happens in Egestion
Faeces (undigested food, bacteria, enzymes, cells) is removed at the anus
What is the salivary glands
Produces saliva (with amylase)
What is the function of the large Intenstine
This is where water is absorbed
What does the liver do
It is the large organ that produces bile
What does the pancreas do
Produces lipase and amylase
What is the role of the gall bladder
This is where bile is stored
What does the stomach contain?
HCl and Protease
Explain how Carbohydrate Digestion works
The products are monosaccharides and absorbed by a co transport mechanism with Na+ into epithelial cells
Explain the process of Absorption
Takes place in ileum (small intestine). Lining is folded into villi and epithelial cells have microvilli to increase available surface area for absorption. Monosaccharides and Amino acids enter blood in capillary
What are the roles of bile?
Where is it produced and stored?
Produced in liver
Stored in gall bladder
Flows down bile duct to duodenum
Neutralises acidic contents in stomach. It contains Bile salts which emulsify fats
What is emulsification
Breaking large fat globules into smaller droplets, increasing available surface area for lipase to work on.
What are micelles
They are made of fatty acids, monoglyerides and bile salts. They transport lipid soluble fatty acids and monoglyerides to the surface of the microvilli where absorption occurs. Monoglyerides and fatty acids diffuse through as they are lipid soluble
What happens in the epithelial cell for lipid digestion
Triglycerides are resynthesised into S.E.R
They combine with cholesterol, protein + phopholipids to form chylomicrons in golgi body. They leave via exocytosis and enter blood system via lymph vessel (lacteal)
What is a chylomicron
Water soluble droplets made of triglycerides, cholesterol, protein +, phospholipid
What are endopeptidases
Protein digestin enzyme which break peptide bonds in the middle of polypeptide chain to form smaller polypeptides. Examples are pepsin + trypsin. It is efficient to do this so more end for exopeptidases to work on
What are exopeptidases
Protein digestin enzyme which breaks the peptide bonds at the end of the chains releasing single amino acids or dipeptides
Describe how proteins are digested
Hydrolysis of peptide bonds
Endopeptidases break polypeptides into smaller peptide chains
Exopeptidases releases single amino acids
Dipeptides break down into amino acids
How is alpha glucose assimilated?
It is absorbed by co-transport with Na+
Where is amylase secreted?
The salivary glands and the pancreas
Where is maltase secreted?
In the small intestine
How are large lipid droplets broken down?
Bile salts are added in the process of emulsification
How are small lipid droplets broken down?
Two ester bonds between fatty acid molecules and glycerol are broken and a monoglyceride and two fatty acids are present as micelles
How are amino acids absorbed?
By co-transport with Na+
