Unit 7 - human nutrition Flashcards
Name the 7 major nutrients, main source & purpose
- Carbohydrates - provide energy. Pasta, bread, fruit.
- Fats - store energy, insulation. Avocado, nuts, olive oil.
- Proteins - growth and repair. Meat, fish, eggs.
- Vitamins - essential for healthy metabolic processes. Fruits, vegetables
- Mineral ions
- Fiber - helps digestion. Vegetables, cereals, fruits.
- Water
State 2 types of vitamins, uses and sources
- Vitamin C - helps wounds heal, maintains healthy blood vessels, skin, etc. Oranges, red pepper, broccoli.
- Vitamin D - helps regulate amount of calcium in body, which is vital for keeping teeth, bones and muscles healthy. Salmon, cheese, eggs.
State 2 types of mineral ions
- Calcium - strengthens bones and teeth, clotting of wounds. Milk, spinach, broccoli.
- Iron - production of hemoglobin (protein that carries oxygen) for red blood cells
What is a balanced diet?
The consummation of all nutrients needed by the body, in correct amounts to maintain health
What is a deficiency disease?
An illness caused by the lack of an essential nutrient in the diet
What disease is caused by the deficiency of vitamin D?
Rickets - symptoms include bone pain, weakness in muscles, bone loss, higher risk of fractures and skeletal deformities
What disease is caused by the deficiency of vitamin C?
Scurvy - symptoms include leg and joint pain, tiredness, weakness, swollen/bleeding gums
Define ingestion
Taking substances (food and drink) into the body through the mouth
Define digestion
Breaking food down into nutrients
Define absorption
The movement of small food molecules and ions through the wall of the intestine into the blood
Define assimilation
The movement of digested food molecules into the cells of the body where they are needed
Define egestion
The passing out food that has not been digested/absorbed
State the step by step processes of the alimentary canal (in depth)
- Food is ingested through the mouth, where through physical digestion it is broken into smaller pieces and turned into bolus (chewed mass). Chemical digestion also occurs here by the enzyme amylase.
- Muscles in the walls of the oesophagus contract and push the bolus into the stomach
- The bolus is chemically digested in the stomach by gastric juices (mix of hydrochloric acid and enzyme pepsin) which breaks down the protein; and lipase. By the time the food is ready to leave, it has turned to chyme (thick liquid)
- The chyme travels to the small intestine, where the nutrients and water inside it is absorbed into the blood stream ( the digested food molecules the assimilate from the blood into the cells of the body where they are used). The folds of the small intestine are covered with villi (finger like extensions) to increase its sa for absorbing nutrients
- The undigested food then travels to the large intestine, where water is removed from it and it is turned into solid waste (faeces). It waits there until it is ready to be released from the anus.
What is chemical digestion?
The break down of large insoluble molecules in food into small soluble molecules with the help of enzymes.
Occurs in: mouth, stomach, small intestine
What is physical digestion?
The breakdown of food into smaller pieces without any chemical changes. This is done to increase the surface area : volume ratio, so that the enzymes have more locations to break down the food further.
Occurs in: mouth
Which organs are in the alimentary canal, in order of how food passes through them?
- Mouth
- Oesaphagus
- Stomach
- Small intestine
- Large intestine
- Anus
What are the 3 parts of the small intestine?
- Duodenum - the first, c-shaped part where enzymes from the pancreases and bile from the liver is added to the chyme
- Jejunum
- Ileum - the final part which absorbs nutrients, vitamin B12 and bile acids. Leads to the large intestine
What are the 3 parts of the large intestine?
- Cecum
- Colon - part in which electrolytes, water and some nutrients are removed. Stool is formed here
- Rectum - collects and holds the stool until it is ready to be released from the anus.
State 4 organs vital to the digestive system that food does not pass through + purpose?
- Salivary glands - glands in the mouth which secrete saliva containing amylase (breaks down starch, makes ingested food soft and easy to swallow)
- Liver - organ which produces bile which helps the body absorb fat and neutralize acidic chyme; Converts extra glucose into glycogen; clears the blood from alcohol and drugs;
- Gall bladder - sac-like structure which stores bile before it is released into the duodenum
- Pancreas - glands located behind the stomach which produce enzymes to help digest nutrients; makes the hormone insulin to control blood sugar levels
Order of stages of digestion
- Ingestion
- Digestion
- Absorption
- Assimilation
- Egestion
What is the purpose of bile?
To emulsify fat into very small droplets. Fat is insoluble, which makes it difficult for lipase enzymes to breakdown. When the fat is emulsified, the sa increases. This allows lipase to digest the fats into fatty acids and glycerol quicker.
- Also can neutralize the acidic mixture of gastric juices and food because amylase and trypsin work nest in alkaline conditions
What is gastric juice + purpose?
- A mixture secreted in the stomach made from hydrochloric acid and pepsin (protease enzyme)
- Has a PH of 1.5 - 3.5 (acid) which is optimum for the enzymes there and it kills bacteria in food
