The Digestive System Nutrients and Digestion

Four Stages of Food Processing: ingestion digestion absorption elimination Digestion – process that breaks food down into smaller particles so it can be absorbed into the blood Once absorbed in blood, nutrients are used by cells Food particles not used are eliminated as waste Digestion Delete text and place photo here.

Mouth: Mechanical- chewing Chemical – Saliva production Stomach: Mechanical – Contracts, churns Chemical – Acid production Mechanical Digestion: When food is mixed, churned, or chewed Chemical Digestion: When food is broken down by chemical reactions Mechanical and Chemical Digestion Delete text and place photo here.Delete text and place photo here.v

Other roles of enzymes Pancreas creates enzymes to break down sugar Enzymes help create energy for your muscles to move Enzymes help your blood to clot An Enzyme is a type of protein that speeds up the rate of a chemical reaction in the body. Enzymes in digestion help digest protein, carbohydrates, and fats Enzymes

Digestive Tract Food passes through these organs mouth esophagus stomach small intestine large intestine Accessory Organs Food doesn’t actually touch these organs, but they are vital to the digestion process: Salivary Glands Liver Gall bladder pancreas Two parts of digestive system Delete text and place photo here.

The Mouth  Mechanical and Chemical Digestion Begin here  Mechanical – chewing  Chemical – saliva  Saliva is produced by three glands located near the mouth  Eating is called “ingestion”

Esophagus  Food leaves the mouth and enters the esophagus  The epiglottis covers opening to windpipe (only air can go through windpipe)  Esophagus is a muscular tube that pushes food into stomach  Waves of muscle contractions that push food through are called peristalsis

The Stomach Stomach is a muscular bag As food enters, stomach expands Mechanical digestion in stomach – food is churned by peristalsis Chemical digestion in stomach – enzymes and hydrochloric acid secreted to break down food Food stays in stomach for 2-4 hours Food turns into watery substance called chyme before it is released

Small Intestine 1 Inch in diameter feet long Chyme leaves stomach and enters duodenum (1 st part of sm. Intestine. Bile from liver is added – breaks up fat particles Most digestion takes place in duodenum Absorption of food takes place by villi Peristalsis forces undigested material to large intestine

Large Intestine Chyme enters large intestine as watery mixture Large intestine’s purpose is to absorb the water After excess water is absorbed, remaining materials become solid Materials may stay in large intestine for up to 3 days

Small Intestine

The Digestive System Nutrients and Digestion

Nutrients Nutrients – substances in food that provide energy and materials for cell development, growth, and repair Energy for your body to function comes from the foods you eat Calorie = a measurement of the amount of energy contained in food Six kinds of nutrients in foods: o Protein o Carbohydrates o Fats o Vitamins o Minerals o Water

Proteins Your body uses proteins for replacement and repair of body cells and for growth Proteins are large molecules made up of amino acids Some amino acids can only be found in foods you eat Foods that contain proteins: Eggs Milk Cheese Meat

Carbohydrates Carbohydrates are body’s main source of energy Three types of carbs: sugar, starch, and fiber Foods that contain carbohydrates: Sugar: fruits, honey, milk Starch: potatoes, anything made from grain Fiber: vegetables and fruits

Fats Also called lipids Necessary for your body to absorb vitamins Provide energy Cushions internal organs Body stores fat to use as energy

Two Types of Fats Unsaturated Fats: Liquid at room temperature, like oils “Good” Fats your body needs Saturated Fats: Solid at room temperature (think bacon grease) Found in animal meats Raises body’s cholesterol levels

Vitamins Nutrients needed in small quantities for growth, body functions, and preventing some diseases are called Vitamins. Two types: Water soluble – Dissolve in water, not stored in body, need to be eaten regularly Fat soluble – Dissolve in fat, stored by the body Vitamins D and K and B are unique – only vitamins your body makes

Minerals Inorganic nutrients that help regulate chemical reactions in your body Body needs about 14 minerals “Trace Mineral” – a mineral your body only needs a small amount of Minerals are found in pretty much all types of foods

Water Next to oxygen, water is the most important factor for survival Cells need water to carry out their processes Human body = about 60% water Why do you get thirsty? Your body sends messages to your brain that you need more water! Brain creates feeling of thirst

Food Pyramid Foods that contain similar nutrients are classified into “food groups.” You should eat a few things from each food group every day – balanced diet Fats, oils, sweets Milk, yogurt cheese Meat, poultry, fish, eggs, nuts, beans Vegetables Fruits Breads and Grains

Eating Healthy Daily Serving and Serving Size Each day you should eat a certain number of servings from each food group Serving size is different for each food Food Labels help you know what nutrients are in your food