Animal nutrition
- 1. NUTRITION IN HUMANS An interactive presentation by Fatima Salman
- 2. All living organisms need to take in nutrients into their bodies in order to be able to produce new cells, carry out metabolic reactions and provide energy. Plants only need to take in inorganic substances, that are carbon dioxide, water and mineral ions. From these inorganic substances, plants make organic ones; that are carbohydrates, proteins and fats. Animals cannot make their own organic substances from inorganic ones, so they have to take in carbohydrates, proteins and fats. All of these nutrients have originally been made by plants. We obtain these nutrients by eating plants, or by eating animals that have eaten plants.
- 3. CARBOHYDRATES The main function of carbohydrates is to provide us with energy, as they are the body’s main source of fuel; they are needed for respiration. Carbohydrates are also needed to form supporting structures, such as the cell walls in plants. They can also be converted into other organic compounds, such as amino acids and fats.
- 5. SOURCES OF CARBOHYDRATES Beans Fruits Milk Vegetables Legumes Nuts Yoghurt Wheat
- 6. FATS The main function of fats is the same as carbohydrates: to provide energy. They are often used as energy stores, and are especially good at this because a gram of fat contains twice the amount of energy as a gram of carbohydrate. Fats are also needed to build cells, because the cell membrane of every cell is made of mostly fats. Stores of fat beneath our skin are helpful for insulating our bodies in cold weather. Another function of fats is to reduce water loss from the skin surface. Glands in our skin secrete an oily substance, that forms a thin layer over our skin surface, reducing the rate of evaporation of water.
- 7. However, an excessive consumption of fats in our diet can be detrimental for our health. It can lead to being overweight or obese, and may lead to illnesses such as heart disease. Therefore, it is usually better to have a moderate amount of unsaturated fats in our diet.
- 8. SATURATED AND UNSATURATED FATS Saturated fats Solid at room temperature Found mainly in animal based foods Raise levels of cholesterol in your blood Unsaturated fats Liquid at room temperature Found in plant foods and fish Good for your body
- 9. SOURCES OF FATS Butter Cheese Fatty meat Olives Eggs Fatty fish Nuts
- 10. PROTEINS Like carbohydrates and fats, protein can also be broken down to release energy in respiration. However, protein has many other functions in living organisms as well. Protein is needed for forming new cells, and is thus very important for growth. All enzymes are proteins, which are needed to catalyse metabolic reactions. Some of our hormones are proteins as well, such as the hormone insulin, which is secreted into our blood by the pancreas to control our blood glucose level.
- 11. Haemoglobin is also a protein found inside red blood cells. It transports oxygen from our lungs to all other parts of our body. Blood plasma contains proteins as well, called plasma proteins. One of them is fibrinogen, which, if a blood vessel is damaged, forms a blood clot across the wound.
- 12. SOURCES OF PROTEIN Milk Meat Seeds Lentils Beans Eggs Seafood
- 13. VITAMINS Vitamins are organic substance, however, unlike the other three substances, they do not provide us with energy, and we need only small quantities of vitamins in our diet. There are several different vitamins, and each one has a particular function in our body. They usually help metabolic reactions take place in our bodies. If there is not a sufficient amount of any particular vitamin in our diet, it can lead to illnesses called deficiency diseases.
- 14. Vitamin C is needed to make collagen, an important protein used to form skin, cartilage, tendons, ligaments, and blood vessels. It is also needed for healing wounds, and repairing bones and teeth. A deficiency disease which results from a lack of Vitamin C in the diet called scurvy. Symptoms of scurvy include skin ulcers and swollen or badly damaged gums
- 15. Vitamin D is needed to absorb the calcium from our food, as calcium is needed to build strong bones and teeth. A shortage of Vitamin D in our diet can lead to the deficiency disease called ‘rickets’. Symptoms of rickets include pain in the bones, bone fractures, and teeth deformities.
- 16. Fresh fruits Vegetables Citrus fruits (lemons, limes and oranges) Dairy products Oily fish Egg yolks Sunlight Sources of Vitamin C Sources of Vitamin D
- 17. MINERAL SALTS Mineral salts are inorganic substances. Mineral salts are needed in our diet for healthy growth and maintenance. An important mineral salt that we should take in our diet is calcium. Calcium is needed for the formation of bones and teeth, and other essential functions like muscle contraction and blood clotting. Another important mineral salt we need is iron. Iron is needed for the formation of haemoglobin. Haemoglobin is a protein found in red blood cells, which transports oxygen around the body.
- 18. Dairy products Fish bones Red meat Dates Figs Pomegranates Spinach Sources of Calcium Sources of Iron
- 19. An insufficient amount of calcium in the diet can lead to the deficiency disease ‘rickets’, in which the bones become weak and brittle. A lack of iron in the diet means that your body cannot make enough healthy red blood cells. This can lead to the deficiency disease called ‘anaemia’. Symtoms of anaemia include feeling tired all the time, fatigue, and weakness.
- 20. FIBRE Fibre is not really a nutrient since we cannot digest it; thus it doesn’t enter our bloodstream at all. However, it is a very important component of a balanced diet because it allows our digestive system to work properly. It’s bulk makes the food keep moving throughout the alimentary canal. Taking a high fibre diet protects us from many diseases, including cancer.
- 21. WATER Water is an essential component of our diet. For humans, it makes up nearly 70% of their body weight. Water has many functions in the body. Substances are dissolved in water in the cytoplasm of cells, allowing them to react together. Blood plasma is mostly water; it transports nutrients dissolved in it. Water also helps us cool down in hot weather. Sweat is mostly water, and as it evaporates from the skin, it cools us down. We obtain most of the water from the fluids we drink, and some of it from fresh fruits and vegetables.
- 22. NOTES AND CREDITS All images have been taken from Google Images and I take no credits for them. Textbook: O Level Biology, by Mary Jones; Oxford Textbook: Biology Matters; Marshall Cavendish Education The internet