6 Animal nutrition

A diet that includes all the nutrients our cells and tissues use.

Protein - broken down to make amino acids. These are used to form other proteins needed by cells. Carbohydrates - broken down to simple sugars for use in respiration. Fats - Helps maintain body temperature. Also a store of energy supply molecules for respiration. Vitamins and minerals - needed in small amounts for correct functioning of body. Fibre - made up of cell wall of plants. Sources - leafy vegetables, and unrefined grains. Important in preventing constipation. Water - necessary for all life processes.

For healthy skin, teeth, gums and lining of blood vessels. Food source - citrus fruits, green vegetables, potatoes. Deficiency disease - scurvy: bleeding gums, wounds not healing properly.

For strong bones and teeth. Food source - fish, egg, liver, cheese, and milk. Deficiency disease - rickets: softening of bone.

Needed for strong teeth and bones, involved in clotting of blood. Food source - milk and eggs. Deficiency disease - rickets: softening of bone.

Needed to make haemoglobin in red blood cells. Food source - red meats, liver and kidneys, leafy green vegetables. Deficiency disease - anaemia: reduction in number of red blood cells, makes you tired and short of breath.

Kwashiorkor. Causes: children were breast-fed and then weaned. Symptoms include: swelling of feet and abdomen, wasting muscles, thinning hair and loss of teeth.

Marasmus. Short for age, very low body fat and muscle. Can be fatal due to dehydration, leading to heart problems and infections.

The taking of substances, e.g. food and drink, into the body through the mouth.

The breakdown of large, insoluble food molecules into small, water soluble molecules using mechanical and chemical processes.

Movement of digested food molecules through the wall of the intestine into the blood.

The movement of digested food molecules into the cells of the body where they are used, becoming part of the cells.

Passing out of food that has not been digested, as faeces, through the anus.

Teeth and tongue break down food into smaller pieces.

Produces liquid saliva, moistens food so it can be easily swallowed and contains enzyme amylase to begin breakdown of starch.

Each lump of swallowed and chewed food, called a bolus, is moved from mouth to stomach via the oesophagus, by waves of, muscle called peristalsis.

Acid and protease enzymes are secreted to start protein digestion; movements of the muscular wall churn up food into a liquid.

Cells in the liver make bile; amino acids not used for making proteins are broken down to form urea, which passes to the kidneys for excretion; excess glucose is removed from the blood and stored as glycogen in liver cells.

Stores bile from the liver; the bile is passed along the bile duct into the small intestine, where it neutralises the stomach acid in the chyme.

Secretes digestive enzymes in an alkaline fluid into the small intestine.

Secretions from gallbladder and pancreas enter the first part of the small intestine to complete the process of digestion; digested food molecules and water are absorbed in the second part of the small intestine.

Water is absorbed from the remaining material.

Faeces are egested through a sphincter.

Mechanical digestion: occurs mainly in the mouth, food is broken down physically into smaller pieces without chemical change. Chemical digestion: breakdown of large insoluble molecules into smaller molecules using chemicals such as enzymes.