Presentation on theme: "The Human Body 35-1. Body Organization Body Tissues 1) Connective – provides body support and connections 2) Epithelial – line exterior body and internal."— Presentation transcript:
Body Tissues 1) Connective – provides body support and connections 2) Epithelial – line exterior body and internal glands and organs 3) Nervous – transmits electrical impulses 4) Muscle – allows the body to move inside and out
By the end of this digestion lesson you should be able to: 1) Explain why your body needs food 2) Explain how the digestive system allows you to use your food 3) Describe the path that food takes through your digestive system 4) Explain the functions of the major structures in the digestive system
Why is eating such a vital part of your day? Your body needs the fuel (energy) that is can extract from your food Your body cells convert the chemical energy stored in your food (calories) into ATP So why not just eat these all day???
Our body needs nutrients like Water Carbohydrates Fats Proteins Vitamins Minerals
Vitamins: Organic molecules that work with enzymes to regulate body processes Diets lacking certain vitamins can have serious consequences 2 Types: Fat-soluble - A, D, E & K; can be stored for future use Water-soluble - B varieties, C, Niacin, Pantothenic acid; can’t be stored in the body
Minerals: Inorganic nutrients needed by the body in small amounts Ex: Calcium, Iron, Magnesium, Sodium, Potassium What are they needed for?
Digestion Breaks down food into small molecules that can be used by our cells Includes the mouth, pharynx, esophagus, stomach, small intestine, large intestine Other helpful structures are the salivary glands, pancreas, and the liver
The Mouth Mechanical digestion - the teeth tear and crush food Chemical digestion - enzymes break down carbohydrates (amylase) and microorganisms (lysozyme) THINK ABOUT IT: Where do the enzymes come from?
The Esophagus The food tube that the bolus travels through to reach the stomach Peristalsis draws the food down The cardiac sphincter prevents food from leaving the stomach
The Stomach Large muscular sac Mechanical Digestion - muscle contractions produce a fluid and food mixture called chyme Chemical Digestion - gastric glands release lubricating mucus, hydrochloric acid, and pepsin What does pepsin do?
The Small Intestine Food enters through the pyloric valve Most chemical digestion and absorption occur here Enzymes from the pancreas, liver and intestine lining continue to break down food Divided into three parts: Duodenum, jejunum, and the ileum
Digestion in the Small Intestine 1) Liver - produces bile to digest fats 2) Pancreas - 1)Produces enzymes that break down carbohydrates (amylase), proteins(trypsin), nucleic acids and fats (lipase) 2)Produces the base, sodium bicarbonate that allows the other enzymes to be effective 3)What else does it do?
Absorption in the Small Intestine Made of folded surfaces covered with villi that increase the surface area for absorption Capillaries line the villi in order to absorb small carbohydrates and proteins Lymph vessels absorb some fats Water, cellulose and undigestible substances leave the small intestine
The Large Intestine Colon Removes the water by absorbing it from the remaining chyme Bacterial colonies produce compounds for the body like vitamin K Wastes are eliminated through the rectum
Food for thought…. 1) Write down on a scrap piece of paper the complete meal you ate for dinner last night. List out each part of your meal. 2) Did you consume a balanced diet? Show what nutrients, vitamins and minerals you ate by writing them next to the food they came from. Use pgs. 974-975 3) What enzymes were hard at work in your stomach???