2 NutrientsNutrients: substances in food that supply energy and raw materials for growth, repair, and maintenanceNutrients needed by body are: water, carbohydrates, fats, proteins, vitamins, and minerals
3 Water Most important nutrient many body processes & chem rxns take place in waterComposes most body fluids
4 Carbohydrates main energy source Sugars broken down by digestive system and placed in blood streamSugars are stored in tissue to create ATP
5 Fats Mainly used for cell membranes Insulation and protection Also used for hormones and myelin sheaths
6 Proteins Raw materials for growth and repair structures Skin and muscleHormones and enzymesInsulinhemoglobin
7 Vitamins Vitamins: organic molecules that regulate body processes Work with enzymesFrom our food; We cannot make them (except vitamin D)
8 Minerals Minerals: inorganic nutrients needed in small amounts Calcium: bonesIron: hemoglobin
9 Gastrointestinal tract: long, winding tube which begins with the mouth and ends with the anus Digestion: process of breaking down food into molecules the body can use
10 Mechanical Digestion Teeth tear food into smaller pieces Tongue and palate form a small ball of food called a bolusEsophagus moves food to stomach by a series of wavelike contractions called peristalsisStomach mixes and churns the food
11 Chemical DigestionSalivary amylase in saliva starts to break down starch into smaller sugars (glucose)Pepsin in stomach starts to break down proteins-* Reason why diabetics have to inject insulin. If taken by mouth the peptide hormone insulin will be broken down into smaller subunits of proteins called amino acids.
12 Esophagus 10 inch tube that connects the pharynx with stomach Located between trachea and spinePeristalsis moves food from pharynx to stomachMucus is secreted in lining to moisten and aid in movement of food
14 Stomach Located between the esophagus and the small intestines sphincters at each end control movement of material in and outContains pepsinContains HCL(hydrochloric acid); acidic environment aids digestionLining secretes mucus to protect stomach wall against being burned by HCL
21 Gall Bladder-Accessory Organ Stores bileAfter eating a meal the gall bladder will contract and squirt bile into small intestine.
22 Pancreas – accessory organ Helps neutralize stomach acidPancreatic enzymes digest carbs, lipids, proteins, and nucleic acids
23 Small Intestines Located between the stomach and the large intestines About 23 ft. longAbout 1 inch in diameterSite of absorption of nutrientsContain villi and microvilli-fingerlike extensions that increase surface areaChemical digestion of lipids, proteins and carbohydratesReceives bile from gall bladder/liver, and enzymes from the pancreas