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1/4 digestive system structures

1/4 digestive system structures






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    1/4 digestive system structures 1/4 digestive system structures Presentation Transcript

    • Do Now1. Which nutrient did we get most of our energy from?2. Which nutrient was most important?3. What was the “ignition” for our body?4. What inorganic substance do we need in small amounts?5. What nutrient is found in milk, cheese, bacon?6. What nutrient is essential for muscle growth and repair?
    • Do Now1. Carbohydrates – get most of our energy2. Water – many reactions take place in it or use it3. Vitamins – they help with starting our enzymes4. Minerals – need them in small amounts5. Fats – found in cheeses, milk, bacon6. Proteins – need for muscle repair and growht
    • Ojbective: How do we start to breakdown the food we eat?
    • What is the purpose of the digestive system? To breakdown food into a usable form  As food passes through the digestive tract, the food is disassembled and taken apart along the way Think of like the stored money in a piggy bank – we have to break it opened to get it! All organs function to convert foods into smaller molecules the body can 1. Absorb 2. Transport 3. Use
    • Types of digestion Mechanical Digestion  Physically breaking down food into smaller pieces  Ex: chewing, stomach contracting Chemical Digestion  Digestive enzymes break bonds in food  Ex: enzymes in your stomach, mouth
    • Human Digestive System One-way canal  One way in  mouth  One way out butt…or anus because We’re in science class
    • Human Digestive System Food passes through:1. Mouth2. Pharynx3. Esophagus4. Stomach5. Small intestine6. Large intestineFood touches all of thesestructures!
    • Human Digestive System Accessory Structures1. Salivary glands2. Pancreas3. LiverAll of these aid in digest.by adding secretions*enzymes, pHFood does not touch thesestructures!
    • Regents ReviewWhich process requires hydrolytic enzymes?1. ingestion2. egestion3. digestion4. excretion
    • Mouth Starts digestion for all food! Has both mechanical and chemical digestion  Mechanical by the teeth, chewing  Chemical by the salivary glands secreting saliva
    • Mouth Saliva  Secreted by salivary glands  moisten the food  Chemical digestion via AMYLASE  Breaks down sugars/starches  Digestion of carbs starts in the mouth!!
    • Esophagus Connects your mouth to your stomach Chewed clump of food is a BOLUS in the esophagus Gravity does NOT push food down  Goes to stomach by PERISTALSIS  contractions of smooth muscle in your esophagus
    • PeristalsisMuscular contractions that push BOLUS of food into stomachNOTE: no digestion takes place in the esophagus; only connection
    • Regents ReviewThe diagram represents a portion of the esophagus. Which is a correctstatement about the process shown in the diagram?1. It transports nutrients within the digestive tract.2. It must occur prior the mechanical digestion of food in the oral cavity.3. It emulsifies fats for hydrolysis in the small intestine4. It increases water absorption by the esophagus.
    • Stomach Large mucus sac  Both mechanical and chemical digestion Starts protein digestion Stomach
    • Stomach Mechanical Digestion  Stomach muscles contract to mix food  Goes from a bolus of food to “CHYME” – food/enzymes/liquid
    • Stomach Chemical Digestion - Lining of stomach secretes:  mucus to protect, moisten  enzyme PEPSIN – starts protein digestion!  HCl to make stomach acidic (pepsin only works at pH of 2) Stomach empties after about an hour or two
    • Regents ReviewThe passage of the end products of digestion into thecells of an organism is an example of1. absorption2. digestion3. circulation4. regulation
    • Regents ReviewWhen most proteins, fats, and carbohydrates aredigested completely, they are converted to endproducts that1. are soluble and can easily pass through cell membranes2. contain long chains of amino acids and fatty acids3. contain atoms of carbon, hydrogen, oxygen and nitrogen4. are a direct result of dehydration synthesis
    • Regents ReviewThe digestion of carbohydrates starts in the_________ with the enzyme _______________1. Mouth; pepsin2. Mouth; amylase3. Stomach; pepsin4. Stomach; amylase
    • Regents ReviewThe digestion of proteins starts in the _________with the enzyme _______________1. Mouth; pepsin2. Mouth; amylase3. Stomach; pepsin4. Stomach; amylase
    • Do Now Where would the chemical digestion of meat start? Where would the chemical digestion of starch start? Which nutrients do you think could be absorbed without being digested in the gastrointestinal tract? Where does the physical digestion of all food start?
    • Do Now Fruit is a complex carbohydrate  Digestion of sugars start in the mouth Starch is a complex carbohydrate  Digestion of sugars start in the mouth Vitamins, Minerals, and Water  No building blocks, right?  Vitamins, Minerals, and Water
    • Objective: What happens to foodafter it moves out of the stomach?
    • A trip through the Gastrointestinal Tract… Food enters through the mouth Become a bolus as we move through the esophagus Become CHYME when we enter the stomach
    • After the stomach… CHYME enters the small intestines
    • Small Intestines Digestion is finished here No digestion after small intestines Absorption of nutrients occurs here!  The surface of small intestines are covered with VILLI  The surfaces of the villi are covered by MICROVILLI
    • Small Intestines Villi and Microvilli (villus and microvillus)  Make the small intestine have HUGE SURFACE AREA…why?  So the most possible absorption of nutrients can take place! Microvilli are like small fingers on finger! Huge surface area!
    • Which set of paper towels can absorb more?
    • After the small intestine…Large Intestine Chyme enters large intestine (colon) After the SI, much of the nutrients have been absorbed out of the chyme already  water, cellulose, undigested material is all that’s left!
    • Large Intestine (Colon) Main function of the colon: Absorbing Water If water cannot be absorbed – Diarrhea  Think: if you don’t absorb the water, where does it go? To help food move better – Roughage  Complex carbs, fiber, vegetables good sources of roughage
    • Enzymes of the Gastrointestinal System Mouth – salivary amylase  Breaks down starches into smaller sugars  Where carbohydrate digestion starts Stomach – pepsin  Breaks down polypeptides into amino acids  Where protein digestion starts
    • Enzymes in the Digestive System Small intestine gets enzymes from two places:  1. the pancreas releases enzymes into the SI  2. the small intestine lining secretes enzymes
    • Enzymes in the Digestive System Small intestine from pancreas  Amylase – continues breakdown of carbohydrate, starch  Trypsin – continues breakdown of protein  Lipase – STARTS break down of fat NOTICE: lipase (lipid); fat digestion starts in the small intestine Small intestine from lining secretions  Maltase, sucrase, lactase – breaks down carbs to sugars  Peptidase – breaks down peptides into amino acids
    • Digestive System – lets go structure by structure and describe it’s role in digestion
    • Citations All pictures taken from PowerPoint clipart and Google Pictures
    • Citations All pictures taken from PowerPoint clipart and Google Pictures All animations taken from Google Pictures