chapter 3 breaking down food Flashcards
what are the types of teeth
incisors
canines
pre - molars
molars
what are the structure of the teeth
pulp cavity enamel - hard put can dissolve in acid dentine nerve endings gum covers the jaw bone blood vessels and nerves cement
what are dentists
dentists are health professionals whi advise on tooth care but also repair the damage caused by poor diet and poor tooth cleaning
what is the function of saliva
it helps neutrailse the acids in the mouth as its alkaline
contains amylase which starts the digestion of starch
dissolves soluble foods without it it would be hard to swallow
what are the benefits of brushing teeth
removes bacteria, or afterwards to remove food particles
- bacteria digest sugar into the food to produce acid
how does tooth decay happen
acidic - dissolves enamel and then the softer sensitive, dentine will be damages and this will expose the pulp and then you would get a tooth ache as the nerve endings are stimulated
why is tooth decay not felt in till it reaches the pulp
because the nerve ending are not yet exposed
how do you reduce the effects of acid
do not eat or drink too much acidic food or drink acidic drinks
drink water with acidc foods to wash it away
clean teeth
how is food moved through the digestive system
the salivary glands, pancreas and gut lining contain specialised cells which produce digestive enzymes
the digestive juices containing these enzymes are passed into the gut where they are mixed with the food
the help the mixing process and push food along the muscular walls of the gut contract and relax this is called peristalsis
the squeezing action of peristalsis brings the enzymes in contact with the food molecules
once mixed the conditions have to be right for the enzymes to work
what is the function of teeth
large particles are broken down physically be teeth
what is peristalsis
a series of wave like muscle contractions that move food to different areas in the gut
process of swallowing
reflex action - this occurs when the tongue pushes the food to the back of your mouth, then the epiglottis covers the opening of the windpipe as you swallow, the slimy mucus in the oesophagus in salvia helps the food slip down
how do you break down carbohydrates
into sugars, by carbohydrase enzyme produced in the salivary glands, pancreas and small intestine. Amylase is a carbohydrase which cataylses the digestion of starch into sugars
how do you break down proteins
into amino acids by protease in acidic conditions in the stomach, the pancreas and small intestine
how do you break down fats
into fatty acids and glycerol by lipase enzymes produced in the pancreas and small intestine
what conditions do enzymes in the stomach work best in
acidic
where is bile produced, stored and how does it get into the small intestine
liver, gall bladder, bile duct
what does bile do
neutralises the stomach acid and emulsifies fat to optimise enzyme activity
where are soluble products of digestion absorbed
into the blood stream in the small intestine
what do the villi do
they increase the surface area for efficient absorption they have cells with microvilli rich blood supply one cell thick wall lymph system
what are amino acids used for
make proteins
what are fatty acids, glycerol and glucose used for
energy release
what happens to excess glucose
its converted to glycogen and fat for storage
what happens to excess amino acids
they are deaminated by the liver and the ammonia produced is converted to urea for excretion
what is water absorbed by
the large intestine
what happens to the indigestible food
the indigestible food and the bacteria make up the faeces which are egested
why do patients with cystic fibrosis have difficulty digesting and absorbing food
due to thick sticky mucus which blocks the pancreatic duct and absorbing surfaces
why do patients with coeliac disease have problems absorbing food
trigged by protein and gluten, this causes the immune system to attack the villi, this reduces the surface area of the villi preventing efficient absorption
