3.3.3 Digestion and Absorption Flashcards
Oesophagus
transports food from mouth to stomach
Stomach
muscular sac, inner layer produces enzymes, stores and digests food (particularly protein)
ileum (small intestine)
where further enzyme digestion occurs
Large Intestine
mostly absorbs water and nutrients
Salivary glands
a duct in the mouth containing amylase
Pancreas
contains pancreatic juices which contain various enzymes
What are the exchange features in the ileum? (5)
- Villi and microvilli increase surface area
- Villi lining and capillary endothelium are one cell thick
- Ileum contain muscle which contracts.
- Well supplied with blood vessels.
- Epithelial cells are dense with carrier proteins for amino acids and glucose
How is many villi and microvilli in the ileum beneficial?
creates a large SA:V ratio
How is the villi lining and capillary endothelium of the ileum being one cell thick beneficial?
Shorter diffusion distance
How is the ileum containing muscles that contract beneficial?
This movement mixes the contents of the ileum and so maintains concentration gradients.
How is the ileum being supplied with blood vessel beneficial?
Blood circulates to maintain concentration gradient
How is the epithelial cells being dense in the ileum with carrier proteins for amino acids and glucose beneficial?
selectively permeable
Role of carbohydrases
Hydrolyses polysaccharides to disaccharides
Role of disaccharidases
Hydrolyse disaccharides to monosaccharides
Role of Lipases
Hydrolyses lipids into monoglycerides and fatty acids
Role of Proteases/ Peptidases (2)
Hydrolyses polypeptides to dipeptides
Hydrolyses dipeptides to amino acids
Where are all these digestive enzymes found?
in the epithelial surface membrane