Human Nutrition Flashcards
(26 cards)
What are proteins?
- Broken down to make animo acids and are then used to form enzymes and other proteins needed by cells
- Protein sources include eggs, milk and milk products, meat, fish, legumes, nuts and seeds
What are carbohydrates?
- Needed to release energy in cells to enable all life processes to take place
- Good sources include rice, bread, potatoes, pasta and yams
What are lipids?
- Fat deposited just beneath the skin, these form insulation to maintain body temperature. Also used as a store of energy for times when the diet doesn’t contain enough energy
- Fat is present in meat and lipids can also come in oils, milk products, nuts, avocados and oily fish
What are vitamins and minerals?
- They are needed in tiny amounts for the correct functioning of the body. Cannot be produced by body and cooking food destroys some vitamins
What is dietary fibre?
- Made up of the cell walls of plants
- Good sources are leafy vegetables and unrefined grains.
- It adds bulk to food so that can be easily moved along the digestive system by peristalsis
Why is water important?
- The major constituent of the body of living organisms and is necessary for all life processes.
- Water is continually being lost by excretion and sweating and must be replaced regularly through food and drink to maintain health
Why is vitamin A important?
- Helps cells to grow and keeps skin healthy, helps eyes see in poor light
- In liver, red and orange vegetables, butter and fish oil
- Deficiency disease - night blindness
Why is vitamin C important?
- For healthy skin, teeth and gums and keeps lining of blood vessels healthy
- In citrus fruit and green vegetables, potatoes
- Deficiency disease - scurvy (bleeding gums, wounds don’t heal properly)
Why is vitamin D important?
- For strong bones and teeth
- Found in fish, eggs, liver, cheese and milk
- Deficiency disease - rickets (softening of bones)
Why is calcium important?
- Needed for strong teeth and bones and involved in clotting of blood
- In milk and cheese
- Deficiency disease - rickets (softening of the bones)
Why is iron important?
- Needed to make haemoglobin in RBCs
- In red meats, liver and kidneys, leafy green vegetables
- Deficiency disease - anaemia (reduction in RBCs, person becomes tired and short of breath)
How do energy requirements vary in people?
- Children need proportionately more protein than adults, for growth, because they are still growing rapidly
- Pregnant women need more iron than usual to supply what the baby needs for making blood cells
- Energy requirements also vary with age and activity levels e.g. an office worker will need less energy than a manual worker
What happens in the mouth?
Teeth and tongue break down food into smaller pieces. Saliva from salivary glands moistens food so it is easily swallowed and contains the enzyme amylase to begin breakdown of starch
What happens in the oesophagus?
Each lump of swallowed food, called a bolus, is moved from the mouth to the stomach by waves of a muscle contraction called peristalsis
What happens in the stomach?
Food enter through a ring of muscle. Acid and protease enzymes are secreted to start protein digestion. Movements of the muscular wall churn up food into a liquid and the partly digested food passes a little at a time into the small intestine
What happens in the liver?
Cells in liver make bile. Animo acids not used for making proteins are broken down and make urea. Excess glucose is removed from blood and stored as glycogen in liver cells
What happens in gall bladder?
Stores bile from liver, bile is passed along bile duct into small intestine where it neutralises the stomach acid and emulsifies lipids
What happens in the pancreas?
Secretes amylase, lipase and protease enzymes as well as sodium hydrogen-carbonate into small intestine
What happens in the small intestine?
Secretions from gall bladder and pancreas as well as further enzymes from wall of small intestine walls to complete digestion. The digested food is absorbed into blood through the villi
What happens in the large intestine?
In colon, water and some vitamins are absorbed from remaining material. In the rectum, the remaining material (faeces), made up of indigestible food is compactes and stored
What does amylase do and where is it found?
Amylase breaks starch down into maltose. Secreted by the salivary glands and pancreas
What does maltase do and where is it found?
Maltase breaks maltose down into glucose. It is secreted by the small intestine
What does protease do and where is it found?
Protease breaks proteins down into amino acids. It is secreted in the stomach, pancreas and small intestine
What does lipase do and where is it found?
Lipase breaks lipids down into glycerol and fatty acids. It is secreted by the pancreas and small intestine
