human digestive system Flashcards
why must most food be digested
- to breakdown food into small and soluble molecules
- can be absorbed into the blood quickly
- can be transported to other parts of the body/ used for various purposes
what is the sequence of the digestive system
- mouth
- gullet
- stomach
- small intestine
- large intestine
- rectum
- anus
what do we not need to digest
Some substances in food, for example glucose (simple sugar) in fruit, are already soluble and small, and so can be absorbed into the wall of the intestine without being digested.
what are things that we cannot digest (indigestable)
- cellulose(cell wall of plant cells, supplies fibre) remains undigested in the human alimentary canal.
- We don’t have the enzymes to digest fibre
what are the types of digestion
(2 types)
- chemical
- physical
what are enzymes
- Biological molecules produced by cells of the digestive system
- Specific to a particular substance
what are the different types of enzymes
(3 types)
- Carbohydrase
- Protease
- Lipase
what is carbohydrase
an enzyme that digests carbohydrates
what is the end product of carbohydrates
after being digested by carbohyrase
simple sugars
what is protease
an enzymes that digests proteins
what is the end product of proteins
after being digested by protease
amino acids
what is lipase
an enzyme that digests lipids / fats
what is the end product of lipids
after being digested by lipase
fatty acid and glycerol
why is it important to break down food physically
increase surface area for enzyme action
what types of digestive happens in the mouth
- chemical
- physical
what is the chemical digestion that happens in the mouth
saliva contains enzymes that digest carbohydrates
what is the physical digestion that happens in the mouth
teeth: breaks food down into smaller, simpler, soluble
what digestion happens in the gullet/esophagus
no digestion(technically) but the enzymes from the mouth are still digesting carbohydrates
what does the gullet/esophagus do
When the ball of food is swallowed, it travels along a short, narrow muscular tube (gullet) which is connected to the stomach.
what digestion happens in the stomach
- physical
- chemical
what is the physical digestion that happens in the stomach
the muscular walls of the stomach continue physical digestion through the churning action.
what is the chemical digestion that happens in the stomach
The walls of the stomach secrete gastric juices, which contains a mixture of hydrochloric acid and protease (an enzyme that digests proteins).
what does the hydrochloric acid in the stomach do
- lowers the pH in the stomach
- kills bacteria and micro-organisms which might be present in our food.
what does the the mucus layer in the stomach do
protects stomach tissues from the hydrochloric acid and enzymes
where are the muscles in the stomach located at
start and end (both ends of the stomach)
why are there muscles at the ends of your stomach
control the entry and leaving of food into the stomach
what digestion happens in the small intestine
chemical
what is the chemical digestion that happens in the small intestine
produces digestive juices that contain all enzymes that digest carbohydrates, protein and fats
what is the type of digestion that happens in the large intestine
none
what happens in the large intestine
- the remaining water, vitamins and minerals are absorbed.
- As the undigested food travels along the large intestine, it starts to harden due to the loss of water, until it reaches the rectum.
what happens in the rectum
undigested food substances are stored until it is egested through the anus.
what is egested
the passing out of food that has not been digested or absorbed, as faeces, through the anus.
what are simple sugars used for
cellular respiration to release energy
what are amino acids used for
make proteins in the human body
(e.g. collagen)
what are fatty acids and glycerol used for
makes fats in the body
(e.g. for cell membrane)
Will drinking collagen drinks increase collagen production in the body?
not necessarily
why would drinking collagen not necessarily increase collagen production in the body
Digestion, absorption and building new proteins
what is the process after drinking collagen
- digested in the stomach and small intestine
- amino acids → peptide → protein
- absorbed at the small intestine
- New proteins are made in the cells of the body (not necessarily collagen)
what is the effect of excessive sugar in your diet
Diabetes
what is diabetes
inability to regulate blood glucose level / blood sugar level tends to be too high
what is the cause of diabetes
- the inability to produce insulin (a hormone)
- body’s cells are insensitive to insulin
diabetes is also linked to
- Obesity
- Kidney problems
- High blood pressure
- Higher risk of stroke and heart attacks
sympotoms of diabetes
- slow healing of wounds
- constant hunger
- frequent urination
- tingling or numbness in the hands and feet
- unexplained weight loss
- blurred vision
what are the common types of diabetes
- type 1 diabetes
- type 2 diabetes
- gestational diabetes
information about type 1 diaetes
- often hereditary
- usually associated with insuffecient insulin produced by the prancreas
- regular insulin injections are recommended for control
information about type 2 diabetes
- can arise due to genetic and environmental factors
- most common typr of diabetes
risk factors of type 2 diabetes
- 40 and above
- being overweight
- lack of regular physical activity
information about gestational diabetes
- hormonal changes during pregnancy may cause some women to have high blood glucose level
- levels return to normal after delivery
- these women may be at risk of developing type 2 diabetes later in life
how to reduce the risk of diabetes
- Regular health screenings
- Adopt a healthy diet with more wholegrains, lean meat, fruits and vegetables
- Avoid foods that are high in sugars, salt and saturated fats
- Regular exercise (30 minutes per day, 5 days per week)
- Avoid smoking and drinking alcohol in excess
what is the healthy plate
- half plate with vegetables and fruit
- quater with wholegrains
- quater with meat and others
what is constipation
Faeces become hard and dry and the person has trouble passing motion (egestion)
what is the cause of constipation
- insufficient fibre in diet
- stress
- not enough water
- certain medications
what is the consequences of constipation
faeces move through the large intestine at a slower rate, hence more water is absorbed
what is gastric pain cause by
gastritis
what is the cause of gastric pain
- bacterial infection
- skipping meals
- excessive consumption of oily food or alcohol
- too much caffeine
what is the consequences of gastric pain
Painful swelling or inflammation of the stomach lining
what does gastric pain result in
- upper abdominal pain
- nausea
- bloating
what is the cause of food poisoning
bacterial infection
(e.g. cholera or salmonella infection)
what is the consequences of food poisoning
- diarrhoea
- vomiting
how to prevent food poinsoning
- practice handling food in a safe manner
- choosing food carefully
what are the safe food handling methods
(when cooking)
- clean
- separate (uncooked and cooked)
- cook
- chill
why do you need to separate the cooked and uncooked food
Bacterial contamination can occur if raw and cooked foods are not separated properly
what are the safe food handling methods
(buying food)
- bottled milk/drinks are tightly sealed
- food that hasn’t passed expiry date
- do not consume food from cans that are badly dented or bloated
- don’t buy chilled or frozen food that is not stored at the appropriate temperature
- do not consume food that has turned mouldy
what temperature should chilled food be stored at
0° to 4°
what temperature should frozen food be stored at
below -18°
what fermentation can bacteria be used for
- aspergillus
- lactobacillus
- saccharomyces
example of aspergillus
soy sauce
uses lactic acid
example of lactobicillus
- cheese
- yogurt
uses lactic acid
example of saccharomyces
- beer
- wine
- bread
beer - ethanol + CO₂ | wine - ethanol | bread - CO₂
what are stomach ulcers
an open sore in your stomach lining
why the digestion of fats will result in change of pH
fates are broken down into fatty acids and glycerol, fatty acid is acidic
