Digestion. Final Products of Digestion Carbohydrates Disaccharides (sucrose, maltose) Proteins Short polypeptides Individual amino acids

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1 Digestion Process has three stages: 1. Physical Digestion: mechanical process of breaking down the food. Knives and forks, teeth grinding and tearing 2. Chemical Digestion: enzymes and stomach acid breaks these smaller pieces into molecules than can be used 3. Absorption: nutrients enter tiny capillaries in the small intestine. Molecules must be small enough to be absorbed. Are then distributed around the body by the blood. Major Food Components and Their Breakdown Products for Absorption Component of Food Intermediate Products of Digestion Final Products of Digestion Carbohydrates Disaccharides (sucrose, maltose) Monosaccharides (glucose, fructose) Fats Emulsification into smaller droplets Glycerol and fatty acids Proteins Short polypeptides Individual amino acids Minerals and Vitamins Require no digestion, absorbed directly Physical Digestion: The Teeth Teeth physically break down food by cutting and grinding Several different types of teeth Incisors Four in front top, four in front bottom Chisel-shaped for cutting 1

2 Canines Pointy One pair on top, one pair on bottom For tearing and shredding Vampire teeth but according to the book Dracula, the incisors were enlarged, not the canines! Was Dracula a rodent, or was Bram Stoker uninformed? Many herbivores lack these Premolars and Molars Flattened surface Premolars have fewer bumps (cusps) than molars For grinding in humans In carnivores, the top triangular tooth is P4 and the bottom triangular tooth is M1 together they act like a pair of scissors! Human Teeth Two sets in normal humans deciduous and permanent Permanent set has three extra teeth on each side of the jaw (only come in once) Two incisors, one canine, two premolars, three molars (including the wisdom teeth ) per side 2

3 Outside layer of the tooth is enamel the hardest substance in our bodies Enamel cannot be re-grown if chipped or worn Under the enamel is dentine, which is bone-like Sensitive to touch, temperature, acids, sugars Dentine is penetrated by minute tubes that send these sensations to the pulp, inside the tooth, where the nerve resides The root of the tooth connects the pulp to the nervous and circulatory system Root is connected to the jaw through a layer called cementum The Tongue Attached to the floor of the mouth (not the back) Helps move food onto the molars Mixes food with saliva Rolls food into a bolus for swallowing Rough surface is covered with papillae Taste buds are in the furrows around the papillae Some researchers now describe FIVE taste sensations, not four 3

4 Salt tip of tongue Sweet tip of tongue Sour sides of tongue Bitter back of tongue Umami ("meaty" or "savory") newly described, pronounced ooh mommy, location not mentioned in recent articles. Stick parmesan cheese on your tongue to taste it. Salivary Glands Saliva contains amylase, which helps to break down starches into their component sugars Slightly acidic, we make about 1 L per day Moistens food for lubrication Other Structures in the Mouth The Palates The hard palate is the front part of the roof of the mouth The soft palate is at the back of the roof of the mouth The soft palate closes the nasal pharynx so that the food does not go up your nose The Uvula Hangs down from the soft palate The Epiglottis A flap that closes the glottis during swallowing The glottis is the opening to the trachea The pharynx is the place where the tubes at the back of the nose and the back of the mouth meet 4

5 Digestion Process has three stages: 1. Physical Digestion: 2. Chemical Digestion: 3. Absorption: Major Food Components and Their Breakdown Products for Absorption Component of Food Intermediate Products of Digestion Final Products of Digestion Physical Digestion: The Teeth Teeth physically Several different types of teeth Incisors in front top, in front bottom 1

6 Canines on top, on bottom For but according to the book Dracula, the were enlarged, not the! Was Dracula a rodent, or was Bram Stoker uninformed? Many lack these Premolars and Molars surface Premolars have ( ) than molars For (in humans) In carnivores, the top is and the bottom triangular tooth is together they act like a! Human Teeth Two sets in normal humans and Permanent set has on each side of the jaw (only come in once) 2

7 Two, one, two, three (including the ) per side Outside layer of the tooth is the substance in our bodies Enamel cannot be Under the enamel is, which is Sensitive to, Dentine is penetrated by that send these sensations to the, inside the tooth, where the The of the tooth connects the pulp to the and systems is connected to the through a layer called The Tongue Attached to the of the mouth (not the ) Helps Mixes Rolls Rough surface is Taste buds are in the Some researchers now describe taste sensations, not 3

8 (" " or " y") newly described, pronounced ooh mommy, location not mentioned in recent articles. Stick parmesan cheese on your tongue to taste it. Salivary Glands Saliva contains, which helps to break down into their Slightly, we make about Moistens Other Structures in the Mouth The Palates The is the part of the of the mouth The is at the of the of the mouth The soft palate closes the so that the food does not go The Uvula The Epiglottis A that closes the during The is the opening to the The is the place where the at the back of the and the back of the meet 4

Biology 12 - The Digestive System - Chapter Notes

Biology 12 - The Digestive System - Chapter Notes In a nutshell... The body uses a variety of small molecules (amino acids, fatty acids, glucose) for its metabolic needs. Food is mechanically and chemically