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