Digestion Flashcards
What part of the digestive system is responsible for the secretion of bile?
The liver
What is the pancreas’ function in the digestive system?
secretion of enzymes into the duodenum
Secretes pancreatic juices
What is the function of the colon in the digestive system
Reabsorption of water
What is the function of the rectum in the digestive system?
Storages of undigested food prior to removal
What is the function of the stomach in the digestive system?
Mechanical and chemical digestion of proteins in low pH
Where is bile stored?
The gall bladder
How does bile enter the duodenum?
Via the bile duct
How do bile salts help in the digestion of lipids?
Emulsification of the lipids turns them into micelles which makes them more soluble so they are easier to transport and increases SA for chemical digestion with lipase
Why are hydrogen Carbonate ions secreted into the duodenum?
They neutralise the stomach acids
Where would the villus be found in the human gut?
On the epithelial cells in the ileum
What body system is the lacteals part of?
Lymphatic system
Why is is more efficient for the endopeptidases to act before the exopeptidases?
Endopeps break down pepride bonds that are in the middle of the polypeptide chain
Breakd done the chain before the exopeps can break down the external end chain peptide bonds
There is a larger SA for the exopeps to act on and increasing the no. Of external bonds
What are the two types of digestion?
Mechanical
Chemical
Where does mechanical digestion take place?
Teeth and stomach
What does mechanical digestion do?
Breaks down large pieces of food into smaller pieces to increases the SA for chemical digestion which overall increases the rate of digestion
Where does chemical digestion take place?
Enzymes breaking bonds in foods
What does chemical digestion do?
Speeds up the hydrolysis reactions of bonds breaking
Breaks down large insoluble molecules into smaller soluble ones
Why is it necessary that food needs to be digested to be absorbed?
Makes the food smaller and soluble so it can be transported across membrane to be blurbed into the blood plasma
What do glands do in the digestive system?
Produce enzymes
What does the oesophagus do?
Caries food from the mouth to the stomach
What is the function of the ileum in the digestive system?
Food is further digested by enzymes
Absorbs the products of digestion into the bloodstream
What is the function of the salivary glands?
Secretes saliva that contains amylase do break down starch
How does the stomach break down food?
Churns it by using its muscles in the stomach wall
Where are all the places that extracellular enzymes act in the digestive system?
Pancreas into duodenum
Salivary glands into mouth
Gastric glands into stomach
Liver into duodenum (digestive chemicals)
Where does intracellular digestion take place?
In the epithelial cells of the ileum
What are the 3 functions of mucus?
Neutralises acid
Provides lubrication
Protects gut wall from acid erosion
Where is amylase produced?
The salivary glands and the pancreatic juices
What is the optimum pH of amylase?
pH 8
What part of carbohydrate digestion takes place in the mouth and duodenum?
Hydrolysis of starch into maltose
What part of carbohydrate digestion takes place in the ileum?
Maltese hydrolysing maltose into alpha glucose
Describe carbohydrate digestion
Starch is broken down my amylase to produce maltose in the mouth and the duodenum
The amylase hydrolysis the glycosidic bonds
Then in the ileum
Maltase hydrolysis the glycosidic bonds in maltose to alpha glucose
What is the membrane-bound disaccharide?
Maltase = to released into the lumen of the ileum, part of the membranes of the epithelial cells that line the ileum
What is an endopeptidase?
Hydrolyses the peptide bonds between amino acids in the central region of the protein forming smaller polypeptide chains
What is the endopeptidases in digestion called?
Pepsin and trypsin
What is the optimum pH for endopeptidase Pepsi in the stomach?
pH 2
What part of protein digestion takes place in the stomach?
Endopeptidases hydrolysing proteins into smaller polypeptide chains
What are exopeptidases?
Hydrolyses peptide bonds on the terminal amino acids on the end of the polypeptide chain
They release single amino acids and dipeptides
What part of protein digestion takes place in the duodenum?
Exopeptidases hydrolysing polypeptide chains into amino acids and dipeptides
What are the 3 types of exopeptidases?
Carboxypeptidase
Aminopeptidase
Dipeptidase
What is the optimum pH of the endopeptidase trypsin in the duodenum?
pH 8
Why are peptidases secrete in an inactive form?
To protect the gut from harm as they would breakdown the gut
What are dipeptidases?
Hydrolyses the bond between two amino acids in a dipeptide
Membrane-bound part of the epithelial cells of the ileum