digestive system

what is the function of proteins?

for growth and repair of cells and tissues

what is the function of carbohydrates?

the fuel for respiration, the process by which energy is released

what is the function of lipids?

a store of energy and a fuel for respiration

what is the function of water?

used in the blood for plasma for transporting substances

what is the function of vitamins?

Vitamin A : needed for the pigment in eyes and protects the surface

Vitamin C : for healthy skin teeth and gums

Vitamin D : to absorb calcium

what is the function of minerals?

iron forms the haemoglobin which binds to oxygen

calcium is needed to form healthy bones and teeth

what is the function of fibre?

e.g. cellulose → assists the movement of food through the intestine and helps prevent bowel cancer

what is protein broken into?

protease breaks it down into amino acids

what is carbohydrates broken into?

amylase or other carbohydrases breaks it down into glucose

what is lipids broken into?

lipase breaks it down into fatty acids and glycerol

what is water broken into?

doesn’t need to be broken down

what is vitamins broken into?

doesn’t need to be broken down

what is minerals broken into?

doesn’t need to be broken down

what is fibre broken into?

can’t be broken down by enzymes or be digested

what are the functions of bile?

bile emulsifies lipids and neutralises stomach acid

where is amylase made?

salivary glands and pancreas

where does amylase work?

the mouth and the small intestine

what does amylase break down?

carbohydrates

where is protease made?

the stomach and pancreas

where does protease work?

the stomach and small intestine

what does protease break down?

protein

where is lipase made?

pancreas

where does lipase work?

the small intestine

what does lipase break down?

lipids

what are the adaptions of villi?

• its lined with microvilli which provides a large surface area

• villi are one cell thick which provides a short distance for diffusion

• each villus has its own capillary network

in the digestive system, what is the function of the mouth?

by begins digestion by mechanically breaking down food (increases surface area) and mixing it with saliva containing amylase to initiate the digestion of starch.

in the digestive system, what is the function of the oesophagus?

transports food form the mouth to the stomach using muscular contractions called peristalsis

in the digestive system, what is the function of the stomach?

secretes gastric juices containing pepsin, which breaks down proteins into peptides

in the digestive system, what is the function of the small intestine?

enzymes from the pancreas and the lining of the intestine further digest carbohydrates, proteins and lipids. its also where most of the nutrient absorption happens with the help of villi

in the digestive system, what is the function of the large intestine?

absorbs water and minerals forming solid waste to be expelled from the body

in the digestive system, what is the function of the pancreas?

produces digestive enzymes such as amylase, lipase and trypsin, which are released into the small intestine to aid digestion

in the digestive system, what is the function of the liver?

produces bile, which is stored in the gall bladder and released into the small intestine to help emulsify lipids

how is starch broken down?

starch → maltose → glucose

amylase maltase

how is proteins broken down?

proteins → peptides → amino acids

protease (pepsin) trypsin

how is lipids broken down?

lipids → fatty acids + glycerol

lipase