12 8 digestion start
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12 8 digestion start






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    12 8 digestion start 12 8 digestion start Presentation Transcript

    • Do Now1. Identify the nutrient that is the main source of energy.2. Identify the nutrient that is considered 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
    • Objective: How do we start to breakdown the food we eat?
    • Define Digestion To breakdown food into a smaller, usable form Main function of the digestive system  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!
    • 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
    • Types of digestion Mechanical Digestion  Physically breaking down food into smaller pieces  Moistens the food  Ex: chewing, stomach contracting Chemical Digestion  Digestive enzymes break bonds in food  Break food apart without physical parts of your body  Ex: enzymes in your stomach, mouth
    • Human Digestive System One-way canal  One way in  mouth  One way out butt…or anus because were in science class
    • Human Digestive System Food passes through:1. Mouth2. Pharynx3. Esophagus4. Stomach5. Small intestine6. Large intestine
    • Human Digestive System Accessory Structures1. Salivary glands2. Pancreas3. LiverAll of these aid in digest.by adding secretions*enzymes, pH
    • Key Idea The function of the digestive system is to convert foods into smaller molecules the body can 1. Absorb 2. Transport 3. Use
    • Mouth Starts digestion; both mechanical and chemical digestion  Mechanical by the teeth, chewing  Chemical by the salivary glands secreting saliva
    • Mouth Saliva - Secreted by salivary glands  Moistens the food  Chemical digestion via AMYLASE  Breaks down sugars/starches  Digestion of carbs starts in the mouth!!
    • Regents ReviewWhich process requires hydrolytic enzymes?1. ingestion2. egestion3. digestion4. excretion
    • Esophagus Connects your moth to your stomach Chewed clump of food is a BOLUS in the esophagus Gravity does NOT push food down  Can swallow upside 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 types of 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  Secretes enzyme PEPSIN – starts protein digestion!  Lining of stomach secretes HCl to make stomach acidic  Enzyme PEPSIN only works at low pH – about 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 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
    • Citations All pictures taken from PowerPoint clipart and Google Pictures All animations taken from Google Pictures