youtube/watch?v=N2diPZOtty0 Recap of supersize me

http://www.youtube.com/watch?v=N2diPZOtty0 • Recap of supersize me http://www.oprah.com/health/Inside-Dr-Ozs-Digestive-System-Video

Flashcard Warm-up May 22nd • Peristalsis • Define and Draw a picture

Flashcard Warm-up Jan. 2nd

The Digestive System

Anatomy of the Digestive System • The organs of the digestive system can be separated into two main groups: the alimentary canal (also called the gastrointestinal tract) and the accessory digestive organs. • The alimentary canal consists of the following organs: Mouth, Pharynx, Esophagus, Stomach, Small intestine, Large intestine, and Anus Digestive System

II. Overview of Gastrointestinal Processes • Ingestion- putting the food into your mouth! Then, mechanical digestion and chemical digestion begins.

Food Propulsion- The processes that move food to the next digestive organ. • This includes swallowing, peristalsis and segmentation. Howstuffworks "Peristalsis" • Peristalsis- involuntary alternating contraction and relaxation of muscles to squeeze the food through the digestive tract. • Segmentation- single segments of the intestine alternately contract and relax. Because active segments are separated the food is moved forward and then backward. This mixes the food rather than simply propelling through the tract. Digestive Process

Food Breakdown: • Mechanical digestion is mixing of food in the mouth by the tongue, churning of food in the stomach, and segmentation in the small intestine. This prepares the food for chemical digestion.

Chemical Digestion- Enzymes break down food products into their building blocks. Enzymes are located in saliva, stomach, and the pancreas releases enzymes into the intestines that help break down the food. The pancreas enzymes are totally responsible for fat digestion with the enzyme lipase. • Carbohydrates are broken into monosaccharides • (simple sugars) by amylase and maltase.

2. Proteins are broken down into amino acids by PEPSIN and TRYPSIN. 3. Lipids are broken down into fatty acids and glycerol by LIPASE Omega-3 fatty acids have been found to be beneficial for the heart. Positive effects include anti-inflammatory and anti-blood clotting actions, lowering cholesterol and triglyceride levels, and reducing blood pressure. These fatty acids may also reduce the risks and symptoms for other disorders including diabetes, stroke, rheumatoid arthritis, asthma, inflammatory bowel disease, ulcerative colitis, some cancers, and mental decline.

Absorption- The small intestine is the main site where food is absorbed into the blood or lymph. The villi play a huge role in the absorption of food. • Defecation- The elimination of indigestible substances from the body. This is the job of the large intestines. The “residue” spends about 12 to 14 hours in the large intestine as bacteria work to metabolize some of the remaining nutrients, releasing gases that contribute to the odor of feces. You produce about 500 mL of gas per day!

Organs of the Digestive system Accessory digestive organs include the salivary glands, teeth, pancreas, liver and gallbladder. • Salivary glands- contain an enzyme, salivary amylase that begins the process of starch digestion. The saliva also helps bind food together into a mass called a bolus which makes chewing and swallowing easier. • Teeth- aid in mastication, or chewing. This tears and grinds the food breaking it down into smaller pieces.

Pancreas- produces a wide variety of enzymes to help break down food. The enzymes are secreted into the duodenum in an alkaline fluid, which neutralizes the acidic chyme coming in from the stomach. The pancreas also produces the hormones insulin and glucagon.

Liver- The largest organ in your body!! It is located under the diaphragm more to the right side of the body. The liver is connected to the gall bladder via the common hepatic duct. The liver has over 500 known functions!!! Three three important functions are to produce bile, clean your blood, and stores energy in the form of a sugar called glycogen. • Bile is a yellow to green watery solution that contains bile salts, bile pigments (bilirubin a breakdown product of hemoglobin), cholesterol, phospholipids, and a variety of electrolytes. The bile salts help to emulsify fats by physically breaking large fat globules into smaller ones.

Gall Bladder- a thin-walled green sac that sits in the inferior surface of the liver. When food digestion is not occurring bile backs up in the cystic duct and enters the gall bladder where it is stored. If bile is stored for too long or too much water is removed, the cholesterol it contains crystallize to form gallstones

The Alimentary Canal • Mouth- where the food enters the body. The hard palate forms the anterior roof, while the soft palate forms the posterior roof of the mouth. Swallowing or deglutition is completed by the muscular tongue. • Mechanical digestion and chemical digestion begins. Once food is placed in the mouth the physical breakdown begins by chewing. Salivary amylase starts the chemical breakdown of starches and to moisten the food to make swallowing and digestion an easier process. No food absorption occurs in the mouth.

Pharynx- serves as passageway for food and air. Food movement is by alternating contractions of the muscle layers (peristalsis). • The epiglottis closes off the trachea to ensure we do not choke on our food. • Esophagus- the passageway for food only that runs from pharynx to stomach through the diaphragm • Conducts food by peristalsis (slow rhythmic squeezing)- involuntary alternating contraction and relaxation of muscles to squeeze the food through the digestive tract

4) Stomach- located on the left side of the abdominal cavity. Acts as a storage tank for food, a site of food breakdown, chemical breakdown of protein begins, delivers chyme (processed food) to the small intestine. • The internal folds of the stomach mucosa are called rugaethis allows for expansion of the stomach.

Food enters at the cardioesophageal sphincter then enters regions of the stomach. Food empties into the small intestine at the pyloric sphincter.

As the food enters the stomach the walls begins to stretch and the secretion of gastric juices begins. In addition, the presence of food and falling pH levels in the stomach stimulate the stomach cells to secrete the hormone gastrin, prodding the stomach to produce more of the protein-digesting enzymes, mucus and hydrochloric acid. 2 to 3 liters of gastric juice are secreted everyday.

Occasionally the cardioesophageal sphincter fails to close tightly and gastric juice backs up in the esophagus. This is commonly called heartburn. If the acids in the stomach begin digesting the stomach itself this is called a peptic ulcer. Helicobacter pylori (H. pylori) is a bacteria that is the major cause of peptic ulcers. Excessive use of NSAIDs—such as aspirin and ibuprofen—is another common cause.

The stomach works to compress and pummel the food breaking it apart physically. The chemical digestion of proteins also begins in the stomach using enzymes called pepsin. • Once the food is well mixed a rippling peristalsis begins in the lower half of the stomach. The pylorus holds about 30 mL of chyme, and each contraction squirts only 3 mL through the pyloric sphincter into the small intestine. The emptying of the stomach takes about 4 hours after a well-balanced meal, and 6 after a high fat meal to empty.

5) Small Intestine- The body’s major digestive organ, because nearly allnutrient absorption from food occurs in the small intestine. This muscular tube can extend 6-13 feet in a living person. There are three subdivision of the small intestine: • Duodenum- Attached to the stomach and curves around the head of the pancreas • Jejunum- attaches anteriorly to the duodenum • Ileum- extends from jejenum to the large intestine .

Once food reaches the small intestine it is only partially digested. Carbohydrate and protein digestion has begun but no fathas been digested at this point. The journey through the small intestine will take about 3 to 6 hours to complete. Food will be moved through the small intestine using peristaltic contractions and segmented movements to mix the chyme and propel through. • The microvilli of the small intestine have important enzymes, known as brush border enzymes that break down double sugars into simple sugars and complete protein digestion.

Pancreatic juices are also enzyme rich and delivered to the small intestine to complete the digestion of starch, protein, and are totally responsible for fat digestion using lipases, and digest nucleic acids. The pancreatic juice also contains bicarbonate which neutralizes the acidity of the chyme. • The two hormones that regulate the release of pancreatic juice into the small intestine are secretin and cholecystokinin.

Bile also plays a role in fat digestion but is not an enzyme. It acts to emulsify or help break down large fat globules. • The small intestine also contains absorptive cells called villi. These are fingerlike projections that has a rich capillary bed where the digested foodstuffs are absorbed. • At the end of the ileum all that remains is the indigestible food materials and large amounts of bacteria.

6)Large Intestine- Larger in diameter, but shorter than the small intestine this tube extends only 5 feet. Its major functions are to dry out the indigestible food residue by absorbing water and to eliminate these residues from the body as feces. Structures of the large intestine include: • Cecum – saclike first part of the large intestine • Appendix- Accumulation of lymphatic tissue that sometimes becomes inflamed (appendicitis) and hangs from the cecum

Colon- includes the ascending, transverse, descending and sigmoid regions. • Rectum and the anal canal (external opening)

Peristalsis and mass movements (slow-moving powerful contractile waves that move over the colon three to four times a day) are the two propulsive movements occurring in the large intestine. Bulk, or fiber, increases the strength of colon contractions softening the stool and allowing the colon to function properly. • Watery stools or diarrhea results when food passes through the large intestine before water can be absorbed. If food remains in the large intestine for extended periods too much water is absorbed and the stool becomes difficult to pass. This is called constipation, usually due to low fiber diets, “failing to heed the call”, and laxative abuse.

More than 500 vital functions have been identified with the liver. Some of the more well-known functions include the following: • Production of bile, which helps carry away waste and break down fats in the small intestine during digestion • Production of certain proteins for blood plasma • Production of cholesterol and special proteins to help carry fats through the body • Conversion of excess glucose into glycogen for storage (glycogen can later be converted back to glucose for energy) • Regulation of blood levels of amino acids, which form the building blocks of proteins • Processing of hemoglobin for use of its iron content (the liver stores iron) • Conversion of poisonous ammonia to urea (urea is an end product of protein metabolism and is excreted in the urine) • Clearing the blood of drugs and other poisonous substances • Regulating blood clotting • Resisting infections by producing immune factors and removing bacteria from the bloodstream

Discovery education Video • Digestion is the process of breaking down food into a form that can be used by the body’s tissues. Explain the functions of each part of the digestive system. • • What is the role of each part in aiding digestion? • • Why is digestion described as both a mechanical and a chemical process?

Digestive System Poster • Follow directions on 14 A, labels for structures are on 14B • ADD to your poster the FUNCTION of each labeled part • LABEL visible structures of each organ: example- small intestines should have duodenum, jejunum, and ileum labeled • Complete questions on 14 C and D if time, you will have SOME time tomorrow to complete these

Flashcard Warm-up May 23rd • CHEMICAL DIGESTION • List the enzymes discussed in yesterday’s notes • Amylase, maltase, pepsin, trypsin, lipase • Indicate what macromolecule they break down and WHERE this digestion takes place in the body.

III. Activities occurring through the digestive tract Digestion animation • Activities occurring in the mouth, Pharynx, and esophagus 1. Once food is placed in the mouth the physical breakdown begins by chewing. Salivary amylase also contributes to the breakdown of starches and to moisten the food to make swallowing and digestion an easier process. 2. Swallowing or deglutition is aided by the tongue, soft palate, pharynx and esophagus. Once the bolus is forced into the pharynx by the tongue we no longer have conscious control and are into the realm of our reflex activity. 3. The epiglottis closes off the trachea to ensure we do not choke on our food. 4. Food is moved down through the esophagus through peristaltic contractions.

youtube/watch?v=N2diPZOtty0 Recap of supersize me