digestive system Flashcards
what does digestion do
food is broken down into small simple and soluble substances that can be absorbed and used by our body cells through digestion
processes of human nutrition
• ingestion (happens in mouth)
food is taken into the alimentary canal
• digestion (starts in mouth)
food is broken down into simple + soluble molecules
• absorption (large + small intestines)
absorbed food molecules enter the circulatory system (eg. glucose is absorbed into the bloodstream)
• assimilation
absorbed food molecules are taken up by body cells for metabolism (eg. glucose converts into glycogen stored in muscle cells)
• egestion
undigested + in absorbed materials are removed
what happens after we take in food
after we take in food, it is digested and travels through the alimentary canal. the digestive glands produce digestive juices to help digest food
if nitrogen is used as an index of proteins, express the following in terms of nitrogen intake (i) nitrogen in faeces (f) and nitrogen in urine (u)
• amount of proteins digested and absorbed:
• amount of proteins used in growth:
• amount of proteins digested and absorbed: i - p [urine is the amino groups from excess proteins hence is not absorbed]
• amount of proteins used in growth: i - p - u
what does the pancreas do
produces pancreatic juice containing enzymes to help digest food
produces insulin
what does the liver do
produces bile, helps to physically break down fat
what does the gallbladder do
stores bile from liver temporarily, doesn’t produce anything
what does the small intestine do
absorb digested foods
why is the small intestine so long
the length of the small intestine increases the surface area and time for the nutrients in the food to be digested and absorbed
