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B5 Animal nutrition - Coggle Diagram
B5 Animal nutrition
Dental decay
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Many bacteria live in the mouth and most are harmless, however some form a sticky film with saliva, called plaque, which coats teeth and the areas where they attach to gums
To begin with, plaque is soft and easy to remove, however if it hardens and forms tartar, it cannot be removed by brushing
Tartar around the edges of teeth and gums can allow bacteria to work their way into roots, causing gum disease and loss of teeth
If sugar is left in the mouth after eating, bacteria in plaque will feed on it
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The acids gradually dissolve the enamel coating of the teeth, working its way into the dentine
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This is tooth decay and if not dealt with, can cause painful infections and loss of teeth
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Types of teeth
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They are used for chewing to increase the surface area of the food so that it can be exposed to saliva and other digestive juices and broken down more quickly
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Mechanical digestion is the breakdown of food into smaller pieces without chemical change to the food molecules
It is mainly carried out by the chewing action of the teeth, the churning action of the stomach and the emulsification of fats by bile in the duodenum
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Dental health
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Brushing teeth regularly removes the buildup of plaque that can cause gum disease and removes the sugars in the mouth so bacteria cannot turn them into acids and cause tooth decay
Teeth should be brushed with a fluoride toothpaste as this helps to strengthen enamel and reduce damage from acids
Regular visits to a dentist ensures that any signs of gum disease or tooth decay can be dealt with promptly
The role of bile
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The enzymes in the small intestine have a higher (more alkaline) optimum pH than those in the stomach
It breaks down large drops of fat into smaller ones. This is known as emulsification. The larger surface area allows lipase to chemically break down the lipid into glycerol and fatty acids faster
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Proteases
Proteases are a group of enzymes that break down proteins into amino acids in the stomach and small intestine (with the enzymes in the small intestine having been produced in the pancreas)
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Absorption
Absorption is the movement of digested food molecules from the digestive system into the blood (glucose and amino acids) and lymph (fatty acids and glycerol)
Water is absorbed in both the small intestine and the colon, but most absorption of water also happens in the small intestine
Absorption takes place in the second section of the small intestine, the ileum
Carbohydrases
Amylase is secreted into the alimentary canal in the mouth and the duodenum (from the pancreas) and digests starch to maltose (a disaccharide)
Maltose is digested by the enzyme maltase into glucose on the membranes of the epithelium lining the small intestine
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The ileum
The ileum is adapted for absorption as it is very long and has a highly folded surface with millions of villi (tiny, finger like projections)
These adaptations massively increase the surface area of the ileum, allowing absorption to take place faster and more efficiently