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