B3 Digestive system Flashcards
What is the function of the digestive system?
Large insoluble molecules are broken down into small soluble molecules which can be absorbed.
Name the two types of digestion that takes place
Mechanical digestion
Chemical digestion
Name the enzyme found in saliva
Salivary amylase
What is the function of saliva?
Catalyses the hydrolysis of starch
Moistens the food to make it easy to swollow
Where is amylase made in the body?
Salivary glands
Pancreas
Describe the reaction catalysed by amylase
Hydrolysis
Starch –> maltose
Glycogen –> maltose
Name three disaccharides
Lactose
Sucrose
Maltose
Describe the reaction catalysed by maltase
Hydrolysis
Maltose broken down into alpha glucose
Describe the reaction catalysed by lactase
Hydrolysis
Lactose broken down into glucose and galactose
Describe the reaction catalysed by sucrase
Hydrolysis
Sucrose broken down into glucose and fructose
Where are disaccharidases found?
Membrane bound on epithelium of small intestine
Name the structures labelled A-D
A = oesophagus
B = Liver
C = Large intestine
D = Small intestine
Name the structures labelled A-C
A = Gall bladder
B = Stomach
C = Pancreas
Name the parts of the digestive system wall labelled A-C
A = Serosa
B = Layer of muscle
C = Mucosa
Why does the stomach wall produce mucus?
Reduce self digestion
Name the type of cell that produces mucus
Goblet cell
Name the acid produced in the stomach
Hydrochloric acid
Name the type of cell that produces hydrochloric acid
Oxyntic cell
Why does the stomach wall produce hydrochloric acid?
- Activates pepsinogen
- Provides optimum pH for pepsin
- Kills pathogen in food and drink
Name the type of bond broken down by endopeptidases and exopeptidases
Peptide bonds
Name the endopeptidase secreted by gastric glands
Pepsin
Name the exopeptidase secreted by the pancreas
Trypsin
How is pepsinogen activated?
Hydrochloric acid
How is trypsinogen activated?
Enterokinase
The stomach has a pH of ……
pH 1-2
The small intestine has a pH of …….
pH 7
How is the hydrochloric acid neutralised in the small intestine?
Bile and pancreatic juice is alkaline
What effect do bile salts have on lipids?
Emulsifies them to create a large surface area for enzyme action
Where is bile made?
Liver
Where is bile stored?
Gall baldder
Name the enzyme used to hydrolyse lipids
Lipase
The hydrolysis of proteins releases ……..
Amino acids
The hydrolysis of lipids produces …
Fatty acids and monoglycerides
The hydrolysis of starch releases ….
Glucose
Name the structure seen in the diagram
Villus
How is the villus adapted for absorption?
- Large surface area
- Thin walls
- Steep concentration gradient
- Rich blood supply
What is the function of the oesophagus?
Transports food from the mouth to the stomach
Name the process used to push food along the digestive system?
Peristalsis
What is the function of the stomach?
Hydrolysis of protein
By pepsin
What is the function of the small intestine?
Digestion of food
Absorption of digested food
What is the function of the large intestine?
Absorbs water
