Human Nutrition/digestive system Flashcards
What is the function of fats in a balanced diet?
Energy storage; electrical insulation around the nerves; thermal insulation; protects organs
What is the function of carbs in a balanced diet?
Sugars used in respiration to release energy; starch and glycogen are insoluble and store glucose without affecting water potential of cells
Deficient disease of vitamin A?
Night blindness
Which Enzyme digests starch to maltose?
Amylase
How is the ileum specialised for absorption?
Villi on the ileum wall - increase surface area
Microvilli on the surface of the villi - increase surface area
Villi wall once cell thick - short diffusion distance
Capillaries in villi maintain a high concentration gradient.
Lacteal in villi - absorption of fats
Which enzyme digests proteins to amino acids?
Proteases eg pepsin and trypsin
How do you test the energy content of a food sample?
Measure out 25cm3 of water into a boiling tube.
Measure mass of food.
Measure starting temperature of food.
Set light to food using a Bunsen burner and hold under a boiling tube of water until it goes out.
Relight and repeat until it wont catch on fire.
Measure finishing temperature of water and calculate temperature change.
Energy content= volume of water X temperature change X 4.2 divided/ mass of food
Function of pancreas in digestive system?
Produces the enzymes trypsin (protease), lipase and amylase
What is the function of the oesophagus in the digestive system?
Moves food from mouth to stomach using waves of muscular contraction (peristalsis)
Function of rectum in digestive system?
Stores the faces before egestion
Function of vitamin A in a balanced diet?
Used to make rod cells in the retina
Deficiency disease caused by lack of calcium?
Osteoporosis
Function of stomach in digestive system?
Produces protease (pepsin) which digests protein. Produces hydrochloric acid which provides optimum conditions for the enzyme to kill bacteria
Deficiency disease caused by lack of vitamin C?
Scurvy
What enzyme digests maltose to glucose?
Maltase
Function of protein in a balanced diet?
Enzymes; antibodies in immune system; hormones; transport proteins e.g. haemoglobin; muscle
Function of calcium in a balanced diet?
Used to make bones (as calcium phosphate)
Deficient disease caused by lack of iron?
Anaemia
Function of bile?
emulsifys fats - breaks large droplets into smaller droplets, increasing surface area and rate of digestion by lipase. Neutralises stomach acid
Function of vitamin D in a balanced diet?
Helps with absorption of calcium
Function of duodenum in digestive system?
Final site of digestion of carbs, fats, proteins - produces the enzyme maltase
Where is maltase produced?
Ileum
Which enzymes digest fats to fatty acids and glycerol?
Lipase
Function of vitamin C?
Helps form connective tissue, holding organs together
Where is amylase produced?
Pancreas and salivary glands
Where is protease produced
Stomach lining and pancreas
Function of mouth?
Chews food to break it into smaller pieces.
Produces saliva which makes it easier to swallow food. Saliva contains amylase
Where is lipase produced?
Pancreas
What is digestion?
Breakdown of large, insoluble molecules into small, soluble molecules
Function of ileum?
Absorption of small, soluble molecules from the small intestine into the blood
Egestion?
Removal of undigested food via the anus
Function of iron?
Used to make haemoglobin
Function of dietary fibre?
Keeps food moving through digestive system and prevents constipation
Deficiency disease caused by lack of vitamin D?
Ricketts
Function of colon?
Absorbs water into the blood
Whee is bile made and stored?
Made in liver and stored in the gall bladder
