Small Intestine

Question 1

Villi suited for function

Answer 1

-1mm long and covered by single layer of cells
Easier and faster movement of nutrients across membrane
-Inside villi- lacteal and capillary
Nutrients easily diffused into blood/ lymph
-continual movement of villi by muscular contractions of small intestine
Bring villi in contact with new nutrients- enhancing absorption
-microvilli- increases surface area
Faster and more absorption

Question 2

How does absorption of nutrients occur in small intestine

Answer 2

Simple diffusion using concentration gradient
Active process going against gradient
Sugars, amino acids, water-soluble ions enter capillaries
Fatty acid and glycerol recombine in villi to from fat molecule= too large for capillary and therefore enter lacteal along with excess material! later empties into lymph system and blood

Question 3

Chemical digestion of small intestine

Answer 3

Mainly occurs in duodenum
Pancreatic amylase- polysaccharide into monosaccharide (simple sugar)
Trypsin (pancreatic protease)- polypeptide into amino acid
Pancreatic lipase- lipase into fatty acid and glycerol

Question 4

Mechanical digestion of small intestine

Answer 4

Bile- containing bile salts
Crated in pancreas
Emulsifies fat into smaller droplets
Increase lipids surface area which allows pancreatic lipase to break it down further

Question 5

How does Small intestine achieve large surface area

Answer 5

• 6 metres long
• Mucosa (inner lining) has folds
• Villi- finger-like projections on mucosa
• micro villi- smaller projections on villi