2 DIGESTION There are four stages to digestion: INGESTION: eat or taking in foodDEGESTION: breaking down food into nutrientsABSORPTION: the uptake of nutrients into the bodyEGESTION: elimination of waste from the body
3 DIGESTION MECHANICAL: tearing, ripping and beating down of food There are two kinds of digestion:MECHANICAL: tearing, ripping and beating down of foodCHEMICAL: using digestive enzymes to break down food
5 ORAL CAVITYThe oral cavity also contains two kinds of SALIVARY GLANDS:PAROTID: secretes a fluid containing an enzyme that breaks down carbohydratesBUCCAL: secretes mucus which coats the food to prevent it from damaging the digestive tract
6 ESOPHAGUS A long tube that travels from the mouth to the stomach BOLUS: moisten ball of foodFood travels down to the stomach by a process called PERISTALSIS, which is a series of muscle contractions and relaxations.
7 STOMACH Can hold about 1 L of food Does both mechanical and chemical digestionContains a chemical called HYDROCHLORIC ACIDThe acid kills any microbes that may be in the food.The acid also activates enzymes which aid in the breakdown of proteins
8 STOMACHAlso has mucus secreting cells that coat the stomach protecting it from the affects of the acidThe food exits the stomach as a thick liquid called CHYME
9 SMALL INTESTINE Location of the bulk of digestion in the body It is also the location of ABSORPTION in the bodyContains millions VILLI which maximizes the surface area of the small intestine for absorption
10 SMALL INTESTINEThe chyme is acted on by three types of digestive juices:BILE: helps the body absorb fatsPANCREATIC: contains enzymes that break down nutrientsINTESTINAL: works with the other fluids to break down food
11 LARGE INTESTINEThe location of the absorption of water and any other nutrients that the body may need.Produces waste product (poo).
12 ACCESSORY ORGANSThere are organs that help the digestive system, but are not actively involved in digestion.LIVER: produces bileGALL BLADDER: stores bilePANCREAS: produces pancreatic juices
13 DIGESTIVE SYSTEM AND NUTRTRIENTS Carbohydrates are broken down into GLUCOSEFats are broken down into FATTY ACIDSProteins are broken down into AMINO ACIDSVitamins, minerals and water are not broken down; they are used as is
14 ABSORPTION OF NUTRIENTS After digestion, the nutrients are absorbed into the bloodstreamThe nutrients travel to the liver to be processed into forms that the body can useExample: Amino acids can be converted to many different types of proteinsNutrients that are not immediately needed can be stored for future useExample: Excess glucose is converted into glycogen and stored in the liver.
15 HOW NUTRIENTS ARE USEDNutrients are carried throughout the bloodstream to individual cellsThey are used for specialized purposesExample: Glucose is combined with oxygen to produce energyEnergy is used for AUTOMAIC PROCESSES (breathing, digestion, etc.) and PHYSICAL ACTIVITIES (exercise)
16 WASTE REMOVALAfter absorption some waste material and fibre is left in the small intestineThe waste is moved to the large intestine where water, potassium and sodium are removedThe waste is stored in the rectum until it is eliminated