Digestive System & Diet SBI 3U Ms. Raper

All organisms need to obtain energy from essential nutrients. Heterotrophs get energy from other organisms.

Plants are Autotrophs, they make food from simple substances They use the process of photosynthesis to make food.

What is Diet? Diet is everything you eat and drink

Different food groups Carbohydrates Proteins Fats & lipids Starches Sugars Fiber Proteins Fats & lipids Vitamins & Minerals Water

Healthy Diet http://www.hpb.gov.sg/data/hpb.home/media/images/haz/healthy_diet_pyramid.jpg

Canada’s Food Guide

U.S. Food Pyramid http://www.udoerasmus.com/pyramid/pyr_usda.htm

http://www.colorado.edu/studentgroups/wellness/NewFiles/MedFoodPyramid.gif

Vegetarian Food Pyramid http://www.vegetarian-diet.info/images/vegetarian-food-pyramid.jpg http://www.ariseandshine.com/templates/user/default/images/Vegetarian-Food-Pyramid1.jpg

Heart Healthy Pyramid http://www.ariseandshine.com/templates/user/default/images/Vegetarian-Food-Pyramid1.jpg

Indian Food pyramid http://www.diabetesindia.com/diabetes/images/nonveg_triangle.jpg

Want some fun? Check this out….. http://www.beaconlearningcenter.com/WebLessons/RightTrack/food02a.htm

How much do you need? Food provides nutrients for Energy Material for growth and repair Health Energy is measured in Joules (J) Number of joules/day depends on: Age Gender Occupation/activity level

The 5 processes.... Ingestion: taking in food (eating) Digestion: breaking down food into simpler substances. Absorption: digested food passes into the blood. Assimilation: Digested food is used by cells of the body. Egestion: Elimination of waste undigested food.

What happens to the food you eat? Food is made of complex insoluble macro-molecules. Has to be broken down into small soluble micro-molecules (glucose, amino acids, fatty acids and glycerol) Breaking down food into small soluble molecules is called DIGESTION.

Digestion Two types Mechanical Chemical Teeth Muscular contractions Enzymes

http://www.sara-jordan.com/img/a-canal2.jpg

Digestive system A long tube starting at the mouth and ending at the anus

The digestive system consists of A tube lined with glandular cells that secrete digestive juices and enzymes Associated organs Liver Pancreas Gall bladder Salivary glands

Mouth Mechanical digestion Chemical digestion Teeth break food into smaller pieces that increases the surface area for digestion Saliva creates a basic pH of about 8 & moistens food allowing soluble chemicals to dissolve. Chemical digestion 3 pairs of Salivary glands produce the enzyme AMYLASE – this begins the breakdown of STARCH

Salivary Glands Chewed food is mixed with saliva from 3 pairs of salivary glands, the food is now called a BOLUS http://www.orthop.washington.edu/_Rainbow/Album/10357m30355344-9190-45c7-9cdc-c591f8b17bb5.gif

Swallowing… http://www.sghhealth4u.com.sg/Health4U/otolaryngology/Tour_images/swallowing.gif

http://www.dysphagiaonline.com/en/images/Swallowing_Mechanism.jpg

Food is pushed down the esophagus by muscular waves called PERISTALSIS http://www.innerbody.com/anim/mouth.html http://www.phon.ucl.ac.uk/home/shl10/firmfour/img00003.gif

Peristalsis http://www.biotech.um.edu.mt/home_pages/chris/GIT/GITimages/Peristalsis.jpg

The Stomach Food enters the stomach through a valve known as the CARDIAC SPHINCTER The stomach churns the food like a blender. Food is liquefied and now is known as CHYME Food stays in the stomach for several hours http://www.yourdictionary.com/images/ahd/jpg/A4stomac.jpg

The stomach “Epithelial cells line inner surface of the stomach, and secrete about 2 liters of gastric juices per day. Gastric juice contains hydrochloric acid, pepsinogen, and mucus; ingredients important in digestion. Secretions are controlled by nervous (smells, thoughts, and caffeine) and endocrine signals. The stomach secretes hydrochloric acid and pepsin. Hydrochloric acid (HCl) lowers pH of the stomach so pepsin is activated. Pepsin is an enzyme that controls the hydrolysis of proteins into peptides. The stomach also mechanically churns the food. Chyme, the mix of acid and food in the stomach, leaves the stomach and enters the small intestine.” http://www.emc.maricopa.edu/faculty/farabee/biobk/BioBookDIGEST.html

The Pancreas Produces digestive juices through the pancreatic duct. Produces enzymes that digest carbohydrates, proteins and fats. Produces bicarbonate salts to neutralize the stomach acid. The pancreas is also an endocrine organ that produces insulin and glycogen to help in the metabolism of sugar http://www.yourdictionary.com/images/ahd/jpg/A4pancre.jpg

Gall bladder Lies under the liver Stores bile – a greenish liquid Bile emulsifies fats. Has a common duct with the pancreas http://gensurg.co.uk/images/Biliary%20anatomy%20-%20hsk.jpg

http://www. emc. maricopa. edu/faculty/farabee/biobk/BioBookDIGEST http://www.emc.maricopa.edu/faculty/farabee/biobk/BioBookDIGEST.html

Small Intestine The small intestine is where final digestion and absorption occur. The small intestine is a coiled tube over 3 meters long. Coils and folding plus villi give this 3m tube the surface area of a 500-600m long tube. Final digestion of proteins and carbohydrates must occur, and fats have not yet been digested. Villi have cells that produce intestinal enzymes which complete the digestion of peptides and sugars. The absorption process also occurs in the small intestine. Food has been broken down into particles small enough to pass into the small intestine. Sugars and amino acids go into the bloodstream via capillaries in each villus. Glycerol and fatty acids go into the lymphatic system. Absorption is an active transport, requiring cellular energy. http://www.emc.maricopa.edu/faculty/farabee/biobk/BioBookDIGEST.html

Small intestine continued Has an increased surface area due to fingerlike projections called VILLI Produces enzymes that complete the digestion of carbohydrates, proteins and fats. Consists of 3 areas Duodenum Jejunum Ileum

Villi

Villus http://www.colorado.edu/kines/Class/IPHY3430-200/image/villi.jpg

Absorption in Villi

Liver http://www.liverdoctor.com/images/detox_pathways.jpg

Liver… Detoxifies poisons such as alcohol Stores glycogen Deanimates proteins (breaks them down into urea) Produces bile salts Recycles hemoglobin from red blood cells Produces heat

Large Intestine & Appendix Comprised of the ascending, transverse, descending and sigmoid colon Absorbs water, vitamins and minerals Stores waste (feces) Eliminates feces through the anus

http://www.mobyhealth.com/sub/graphics/colon.jpg

Appendix/caecum In humans the appendix has no known function. In herbivores such as rabbits the appendix or caecum is used to digest cellulose.

Conclusion: 5 steps of the process.. Ingestion - taking in food. Digestion – breaking down food. Absorption – digested food goes into the blood. Assimilation – digested food is used by the body. Egestion:- Elimination, waste is removed from the body.

Summary of Digestive Enzymes FOOD TYPE ENZYME SOURCE PRODUCTS CARBOHYDRATES Salivary amylase Pancreatic amylase Maltase Salivary glands Pancreas Small intestine Maltose Glucose PROTEINS Pepsin Trypsin Peptidases Stomach mucosa Intestinal mucosa Peptides Amino acids FATS Lipase Fatty acids and glycerol

Enzymes by source SOURCE ENZYME FOOD PRODUCT MOUTH (salivary glands) Salivary amylase Polysaccharides Maltose STOMACH Pepsin Proteins Peptides PANCREAS Pancreatic amylase Trypsin Lipase Fats Fatty acids and glycerol SMALL INTESTINE Maltase Peptidases Glucose Amino acids

Resources http://www.innerbody.com/htm/body.html http://health.howstuffworks.com/adam-200142.htm http://www.northarundel.com/aniplayer/ http://www.wiley.com/legacy/college/bio/tortora366927/resources/student/anatomydrill/ch24.html http://www.besthealth.com/besthealth/bodyguide/reftext/html/dige_sys_fin.htm l

Salivary gland Teeth Tongue Epiglottis Esophagus Liver Stomach Gall Bladder Duodenum Bile duct Pancreas Colon (Large Intestine) Small Intestine Appendix Rectum (Anus) http://www.lessontutor.com/digestive_system4.gif

Pancreas Gall Bladder Pancreatic Duct Bile duct Duodenum

Cells produce enzymes and Epithelial Lining Cells produce enzymes and absorb digested food Artery Lymph vessel Vein

Digestion of Starch “Carbohydrates are digested in the mouth, stomach and small intestine. The saliva in your mouth contains amylase. If you chew a piece of bread for long enough, the starch it contains is digested to sugar, and it begins to taste sweet.” BBC. Bitesize biology, http://www.bbc.co.uk/schools/ks3bitesize/science/biology/diet_4.shtml

Digestion of Proteins “Proteins are digested in the stomach and small intestine. Digestion of proteins in the stomach is helped by stomach acid, which is strong hydrochloric acid. This also kills harmful micro-organisms that may be in the food.” BBC; bitesize biology. http://www.bbc.co.uk/schools/ks3bitesize/science/biology/diet_4.shtml

Digestion of Fats (lipids) “Digestion of fat in the small intestine is helped by bile, made in the liver. Bile breaks the fat into small droplets that are easier for the lipase enzymes to work on.” BBC; bitesize Biology http://www.bbc.co.uk/schools/ks3bitesize/science/biology/diet_4.shtml

http://www. bbc. co. uk/schools/ks3bitesize/science/biology/diet_5 http://www.bbc.co.uk/schools/ks3bitesize/science/biology/diet_5.shtml http://www.bbc.co.uk/schools/ks3bitesize/science/