http://www.youtube.com/watch?http://www.youtube.com/watch?v=N2diPZOtty0v=N2diPZOtty0 Recap of supersize meRecap of supersize me

http://www.oprah.com/health/Inside-Dr-Ozs-http://www.oprah.com/health/Inside-Dr-Ozs-Digestive-System-VideoDigestive-System-Video

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PeristalsisPeristalsis Define and Draw a pictureDefine and Draw a picture

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The Digestive SystemThe Digestive System

Anatomy of the Digestive Anatomy of the Digestive SystemSystem

A.A. The organs of the digestive system The organs of the digestive system can be separated into two main can be separated into two main groups: the groups: the alimentary canal alimentary canal (also (also called the gastrointestinal tract) called the gastrointestinal tract) and the and the accessory digestive accessory digestive organsorgans..

B.B. The alimentary canal consists of The alimentary canal consists of the following organs: Mouth, the following organs: Mouth, Pharynx, Esophagus, Stomach, Pharynx, Esophagus, Stomach, Small intestine, Large intestine, Small intestine, Large intestine, and Anusand Anus

Digestive SystemDigestive System

II. Overview of Gastrointestinal ProcessesII. Overview of Gastrointestinal ProcessesA.A. Ingestion- putting the food into your mouth! Then, Ingestion- putting the food into your mouth! Then,

mechanical digestion and chemical digestion mechanical digestion and chemical digestion begins. begins.

Food Propulsion- The processes that Food Propulsion- The processes that move food to the next digestive organmove food to the next digestive organ. .

This includes swallowing, peristalsis and This includes swallowing, peristalsis and segmentation. segmentation.

Howstuffworks "Peristalsis"Howstuffworks "Peristalsis" Peristalsis- Peristalsis- involuntary alternating contractioninvoluntary alternating contraction

and relaxation of muscles to squeeze the food and relaxation of muscles to squeeze the food through the digestive tract. through the digestive tract.

Segmentation- single Segmentation- single segments of the segments of the intestine alternately contractintestine alternately contract and relax. and relax. Because active segments are separated the Because active segments are separated the food is moved forward and then backward. food is moved forward and then backward. This This mixes the foodmixes the food rather than simply rather than simply propelling through the tract.propelling through the tract.

Digestive ProcessDigestive Process

Food Breakdown:Food Breakdown: Mechanical digestion is mixing of food in the Mechanical digestion is mixing of food in the

mouth by the tongue, churning of food in the mouth by the tongue, churning of food in the stomach, and segmentation in the small stomach, and segmentation in the small intestine. This intestine. This prepares the food for chemical prepares the food for chemical digestiondigestion..

Chemical Digestion- Enzymes Chemical Digestion- Enzymes break down food break down food products into their building blocksproducts into their building blocks. Enzymes are . Enzymes are located in saliva, stomach, and the located in saliva, stomach, and the pancreas pancreas releases enzymes into the intestines that help break releases enzymes into the intestines that help break down the food. The down the food. The pancreas enzymes are totally pancreas enzymes are totally responsible for fat digestion responsible for fat digestion with the enzyme lipase.with the enzyme lipase.

Carbohydrates are broken into Carbohydrates are broken into monosaccharidesmonosaccharides (simple sugars) by amylase and maltase.(simple sugars) by amylase and maltase.

2. Proteins are broken down into 2. Proteins are broken down into amino acids amino acids by PEPSIN and TRYPSINby PEPSIN and TRYPSIN. .

3. Lipids are broken down into 3. Lipids are broken down into fatty acids and fatty acids and glycerol by LIPASEglycerol 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 Absorption- The small intestine is the small intestine is the main site where food is absorbedmain site where food is absorbed into into the blood or lymph. The the blood or lymph. The villi play a villi play a huge rolehuge role in the absorption of food. in the absorption of food.

Defecation- The Defecation- The elimination of elimination of indigestible substancesindigestible substances from the from the body. This is the job of the large body. This is the job of the large intestines. The “residue” spends intestines. The “residue” spends about about 12 to 14 hours12 to 14 hours in the large in the large intestine as bacteria work to intestine as bacteria work to metabolize some of the remaining metabolize some of the remaining nutrients, releasing gases that nutrients, releasing gases that contribute to the odor of feces. You contribute to the odor of feces. You produce about 500 mL of gas per day!produce about 500 mL of gas per day!

Organs of the Digestive system Organs of the Digestive system Accessory digestive organs include the salivary Accessory digestive organs include the salivary

glands, teeth, pancreas, liver and gallbladder.glands, teeth, pancreas, liver and gallbladder.

Salivary glands- contain an Salivary glands- contain an enzyme, salivary amylase that enzyme, salivary amylase that begins the process of starch begins the process of starch digestiondigestion. The saliva also . The saliva also helps bind food together into a helps bind food together into a mass called a mass called a bolusbolus which which makes chewing and makes chewing and swallowing easier.swallowing easier.

Teeth- aid in mastication, or Teeth- aid in mastication, or chewingchewing. This tears and grinds . This tears and grinds the food breaking it down into the food breaking it down into smaller pieces. smaller pieces.

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

Liver- The Liver- The largest organ in your bodylargest organ in your body!! It is !! It is located under the diaphragm more to the right located under the diaphragm more to the right side of the body. The liver is connected to the side of the body. The liver is connected to the gall bladder via the common hepatic duct. The gall bladder via the common hepatic duct. The liver has over 500 known functions!!! Three liver has over 500 known functions!!! Three three important functions are to produce bile, three important functions are to produce bile, clean your blood, and stores energy in the clean your blood, and stores energy in the form of a sugar called form of a sugar called glycogen.glycogen.

Bile is a Bile is a yellow to green watery solutionyellow to green watery solution that that contains bile salts, bile pigments (bilirubin a contains bile salts, bile pigments (bilirubin a breakdown product of hemoglobin), breakdown product of hemoglobin), cholesterol, phospholipids, and a variety of cholesterol, phospholipids, and a variety of electrolytes. The bile salts electrolytes. The bile salts help to emulsify help to emulsify fatsfats by physically breaking large fat globules by physically breaking large fat globules into smaller ones. into smaller ones.

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

The Alimentary CanalThe Alimentary Canal• Mouth-Mouth- where the food enters the body. The where the food enters the body. The

hard palate forms the anterior roofhard palate forms the anterior roof, while the , while the soft palate forms the posterior roof of the soft palate forms the posterior roof of the mouth. mouth. Swallowing or deglutitionSwallowing or deglutition is is completed by the muscular completed by the muscular tongue.tongue.

Mechanical digestion and chemical digestion Mechanical digestion and chemical digestion begins. Once food is placed in the mouth the begins. Once food is placed in the mouth the physical breakdown begins by chewingphysical breakdown begins by chewing. . Salivary amylase starts the chemical Salivary amylase starts the chemical breakdown of starchesbreakdown of starches and to moisten the food and to moisten the food to make swallowing and digestion an easier to make swallowing and digestion an easier process. No food absorption occurs in the process. No food absorption occurs in the mouth.mouth.

• Pharynx- serves as Pharynx- serves as passageway passageway for food and airfor food and air. Food movement is . Food movement is by by alternating contractions of the alternating contractions of the muscle layers (peristalsis).muscle layers (peristalsis).

The The epiglottis closes off the tracheaepiglottis closes off the trachea to to ensure we do not choke on our food.ensure we do not choke on our food.

• Esophagus- the Esophagus- the passageway for food passageway for food onlyonly that runs from pharynx to stomach that runs from pharynx to stomach through the diaphragmthrough the diaphragm

Conducts food by Conducts food by peristalsis (slow rhythmic peristalsis (slow rhythmic squeezing)squeezing)- - involuntary alternating involuntary alternating contractioncontraction and relaxation of muscles to and relaxation of muscles to squeeze the food through the digestive tractsqueeze the food through the digestive tract

4) Stomach- located on the 4) Stomach- located on the left side left side of the abdominal cavityof the abdominal cavity. Acts . Acts as a storage tank for food, a as a storage tank for food, a site of food breakdown, site of food breakdown, chemical breakdown of protein chemical breakdown of protein begins, begins, delivers chyme delivers chyme (processed food) to the small (processed food) to the small intestine.intestine.

The internal folds of the The internal folds of the stomach mucosa are called stomach mucosa are called rugae rugae this allows for this allows for expansion of the stomach. expansion of the stomach.

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

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

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

The The stomach works to compress and stomach works to compress and pummel the foodpummel the food breaking it apart breaking it apart physically. The chemical digestion of physically. The chemical digestion of proteins also begins in the stomach proteins also begins in the stomach using using enzymes called pepsinenzymes called pepsin..

Once the food is well mixed a Once the food is well mixed a rippling rippling peristalsis begins inperistalsis begins in the lower half of the the lower half of the stomach. The stomach. The pylorus holds about 30 pylorus holds about 30 mLmL of chyme, and each contraction of chyme, and each contraction squirts only 3 mL through the pyloric squirts only 3 mL through the pyloric sphincter into the small intestine. The sphincter into the small intestine. The emptying of the stomach takes about emptying of the stomach takes about 4 4 hours after a well-balanced mealhours after a well-balanced meal, and , and 6 6 after a high fat after a high fat meal to empty.meal to empty.

5) Small Intestine- The body’s major 5) Small Intestine- The body’s major digestive organ, because nearly digestive organ, because nearly allall nutrient absorptionnutrient absorption from food occurs in from food occurs in the small intestine. This muscular tube the small intestine. This muscular tube can extend 6-13 feet in a living person. can extend 6-13 feet in a living person. There are three subdivision of the small There are three subdivision of the small intestine:intestine:

DuodenumDuodenum- Attached to the stomach - Attached to the stomach and curves around the head of the and curves around the head of the pancreaspancreas

JejunumJejunum- attaches anteriorly to the - attaches anteriorly to the duodenumduodenum

Ileum-Ileum- extends from jejenum to the extends from jejenum to the large intestinelarge intestine

..

Once food reaches the small intestine it Once food reaches the small intestine it is only partially digested. Carbohydrate is only partially digested. Carbohydrate and protein digestion has begun but and protein digestion has begun but no no fatfat has been digested at this pointhas been digested at this point. The . The journey through the small intestine will journey through the small intestine will take about take about 3 to 6 hours to complete3 to 6 hours to complete. . Food will be moved through the small Food will be moved through the small intestine using intestine using peristaltic contractions peristaltic contractions and segmented movementsand segmented movements to mix the to mix the chyme and propel through.chyme and propel through.

The microvilli of the small intestine have The microvilli of the small intestine have important enzymes, known as important enzymes, known as brush brush border enzymesborder enzymes that break down double that break down double sugars into simple sugars and sugars into simple sugars and complete complete protein digestionprotein digestion. .

Pancreatic juices are also enzyme Pancreatic juices are also enzyme richrich and delivered to the small and delivered to the small intestine to complete the digestion of intestine to complete the digestion of starch, protein, and are starch, protein, and are totally totally responsible for fat digestion using responsible for fat digestion using lipaseslipases, and digest nucleic acids. , and digest nucleic acids. The pancreatic juice also contains The pancreatic juice also contains bicarbonate which neutralizes bicarbonate which neutralizes the the acidity of the chyme.acidity of the chyme.

The two hormones that regulate the The two hormones that regulate the release of pancreatic juice into the release of pancreatic juice into the small intestine are small intestine are secretin and secretin and cholecystokinincholecystokinin. .

Bile also plays a role in fat digestionBile also plays a role in fat digestion but is not an enzyme. It acts to but is not an enzyme. It acts to emulsify or help break downemulsify or help break down large fat large fat globules.globules.

The small intestine also contains The small intestine also contains absorptive cells called villiabsorptive cells called villi. These are . These are fingerlike projections that has a fingerlike projections that has a rich rich capillary bed where the digested capillary bed where the digested foodstuffs are absorbedfoodstuffs are absorbed. .

At the end of the ileum all that remains At the end of the ileum all that remains is the indigestible food materials and is the indigestible food materials and large amounts of bacteria. large amounts of bacteria.

6)6) Large Intestine- Larger in diameter, but Large Intestine- Larger in diameter, but shorter than the small intestine this shorter than the small intestine this tube extends only 5 feet. Its tube extends only 5 feet. Its major major functions are to dry out the functions are to dry out the indigestible food residue by absorbing indigestible food residue by absorbing waterwater and to eliminate these residues and to eliminate these residues from the body as feces. Structures of from the body as feces. Structures of the large intestine include:the large intestine include:

a)a) CecumCecum – saclike first part of the – saclike first part of the large intestinelarge intestine

b)b) AppendixAppendix- Accumulation of - Accumulation of lymphatic tissue that sometimes lymphatic tissue that sometimes becomes inflamed (appendicitis) becomes inflamed (appendicitis) and and hangs from the cecumhangs from the cecum

a)a) ColonColon- includes the - includes the ascending, transverse, ascending, transverse, descending and sigmoid descending and sigmoid regions.regions.

b)b) Rectum and the anal Rectum and the anal canal (canal (external openingexternal opening) )

Peristalsis and mass movementsPeristalsis and mass movements (slow-moving powerful (slow-moving powerful contractile waves that move over the colon three to four times a contractile waves that move over the colon three to four times a day) are the two propulsive movements occurring in the large day) are the two propulsive movements occurring in the large intestine. Bulk, or intestine. Bulk, or fiber, increases the strength of colonfiber, increases the strength of colon contractions softening the stool and allowing the colon to contractions softening the stool and allowing the colon to function properly.function properly.

Watery stools or diarrhea results when Watery stools or diarrhea results when food passes through the food passes through the large intestine before water can be absorbedlarge intestine before water can be absorbed. If food remains . If food remains in the large intestine for extended periods too much water is in the large intestine for extended periods too much water is absorbed and the stool becomes difficult to pass. This is called absorbed and the stool becomes difficult to pass. This is called constipation, usually due to low fiber diets, “failing to heed the constipation, usually due to low fiber diets, “failing to heed the call”, and laxative abuse.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 VideoDiscovery education Video

Digestion is the process of breaking down Digestion is the process of breaking down food into a form that can be used by the food into a form that can be used by the body’s tissues. Explain the functions of each body’s tissues. Explain the functions of each part of the digestive system. part of the digestive system.

• • What is the role of each part in aiding What is the role of each part in aiding digestion? digestion?

• • Why is digestion described as both a Why is digestion described as both a mechanical and a chemical process? mechanical and a chemical process?

Digestive System PosterDigestive System Poster Follow directions on 14 A, labels for structures Follow directions on 14 A, labels for structures

are on 14Bare on 14B ADD to your poster the FUNCTION of each ADD to your poster the FUNCTION of each

labeled part labeled part LABEL visible structures of each organ: example- LABEL visible structures of each organ: example-

small intestines should have duodenum, jejunum, small intestines should have duodenum, jejunum, and ileum labeledand ileum labeled

Complete questions on 14 C and D if time, you Complete questions on 14 C and D if time, you will have SOME time tomorrow to complete thesewill have SOME time tomorrow to complete these

Flashcard Warm-up May 23Flashcard Warm-up May 23rdrd

CHEMICAL DIGESTIONCHEMICAL DIGESTION

List the enzymes discussed in yesterday’s List the enzymes discussed in yesterday’s notes notes Amylase, maltase, pepsin, trypsin, lipaseAmylase, maltase, pepsin, trypsin, lipase Indicate what macromolecule they break Indicate what macromolecule they break

down and WHERE this digestion takes place down and WHERE this digestion takes place in the body. in the body.

III. Activities occurring through the digestive tractIII. Activities occurring through the digestive tractDigestion animationDigestion animation

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