Flashcard Warm-up 31 Digestive system : made of the alimentary canal (a.k.a, the gastrointestinal tract) and the accessory digestive organs. The alimentary.

Flashcard Warm-up 31Flashcard Warm-up 31Digestive system Digestive system : made of the : made of the alimentary alimentary

canal canal (a.k.a, the gastrointestinal tract) (a.k.a, the gastrointestinal tract) and the and the accessory digestive organsaccessory digestive organs..

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

Accessory digestive organs: (organs that help in the Accessory digestive organs: (organs that help in the digestive process are) : salivary glands, teeth, pancreas, digestive process are) : salivary glands, teeth, pancreas, liver and gallbladder.liver and gallbladder.

The Digestive SystemThe Digestive System

Anatomy of the Digestive SystemAnatomy of the Digestive SystemA.A. The organs of the digestive system can be separated into two The organs of the digestive system can be separated into two

main groups: the main groups: the alimentary canal alimentary canal (also called the (also called the gastrointestinal tract) and the gastrointestinal tract) and the accessory digestive organsaccessory digestive organs..

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

1)1) Mouth-Mouth- where the food enters the body. The where the food enters the body. The hard palate hard palate forms the anterior roofforms the anterior roof, while the soft palate forms the , while the soft palate forms the posterior roof of the mouth. The muscular posterior roof of the mouth. The muscular tongue aids in tongue aids in swallowing foodsswallowing foods..

2)2) Pharynx- serves as Pharynx- serves as passageway for food and airpassageway for food and air. Food . Food movement is by movement is by alternating contractions of the muscle alternating contractions of the muscle layers (peristalsis).layers (peristalsis).

3)3) Esophagus- the Esophagus- the passageway for food onlypassageway for food only that runs from that runs from pharynx to stomach through the diaphragm, Conducts food pharynx to stomach through the diaphragm, Conducts food by by peristalsis (slow rhythmic squeezing)peristalsis (slow rhythmic squeezing)

Digestive System

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

a)a) Food enters at the Food enters at the cardioesophageal sphinctercardioesophageal sphincter then enters then enters regions of the stomach. Food empties into the small intestine regions of the stomach. Food empties into the small intestine at the at the pyloric sphincterpyloric sphincter. The internal folds of the stomach . The internal folds of the stomach

mucosa are called mucosa are called rugae.rugae.

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

a)a) DuodenumDuodenum- Attached to the stomach and curves around the - Attached to the stomach and curves around the head of the pancreashead of the pancreas

b)b) JejunumJejunum- attaches anteriorly to the duodenum- attaches anteriorly to the duodenum

c)c) Ileum-Ileum- extends from jejenum to the large intestine extends from jejenum to the large intestine d)d) The small intestine also contains The small intestine also contains absorptive cells called villiabsorptive cells called villi. .

These are fingerlike projections that has a These are fingerlike projections that has a rich capillary bed rich capillary bed

where the digested foodstuffs are absorbedwhere the digested foodstuffs are absorbed..

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

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

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

c)c) ColonColon- includes the ascending, transverse, descending and - includes the ascending, transverse, descending and

sigmoid regions.sigmoid regions. d)d) Rectum and the anal canal (Rectum and the anal canal (external openingexternal opening) )

C. Accessory digestive organs include the salivary glands, teeth, C. Accessory digestive organs include the salivary glands, teeth, pancreas, liver and gallbladder.pancreas, liver and gallbladder.

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

2.2. Teeth- aid in mastication, or chewingTeeth- aid in mastication, or chewing. This tears and grinds . This tears and grinds

the food breaking it down into smaller pieces.the food breaking it down into smaller pieces. 3.3. Pancreas- Pancreas- produces a wide variety of enzymesproduces a wide variety of enzymes to help break to help break

down food. The enzymes are secreted into the duodenum in down food. The enzymes are secreted into the duodenum in an alkaline fluid, which an alkaline fluid, which neutralizes the acidic chymeneutralizes the acidic chyme coming in coming in from the stomach. The pancreas also produces the hormones from the stomach. The pancreas also produces the hormones insulin and glucagoninsulin and glucagon. .

4.4. Liver- The Liver- The largest organ in your bodylargest organ in your body!! It is located under the !! It is located under the diaphragm more to the right side of the body. The liver is diaphragm more to the right side of the body. The liver is connected to the gall bladder via the common hepatic duct. connected to the gall bladder via the common hepatic duct. This large organ has many metabolic and regulatory roles, This large organ has many metabolic and regulatory roles, however, its digestive function is to however, its digestive function is to produce bileproduce bile. .

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

5) Gall Bladder- a thin-walled green sac that 5) Gall Bladder- a thin-walled green sac that sits in the inferior surface sits in the inferior surface of the liverof the liver. When food digestion is not occurring bile backs up . When food digestion is not occurring bile backs up in the cystic duct and enters the gall bladder where it is stored. 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 If bile is stored for too long or too much water is removed, the cholesterol it contains crystallize to form gallstonescholesterol it contains crystallize to form gallstones. .

Digestion AnimationDigestion AnimationII. Overview of Gastrointestinal ProcessesII. Overview of Gastrointestinal ProcessesA.A. Ingestion- putting the food into your mouth! Then, mechanical Ingestion- putting the food into your mouth! Then, mechanical

digestion and chemical digestion begins. The digestion and chemical digestion begins. The enzyme salivary enzyme salivary amylaseamylase in your saliva in your saliva begins to break down begins to break down starchesstarches. No food . No food absorption occurs in the mouth. Food Propulsion- The absorption occurs in the mouth. Food Propulsion- The processes that processes that move food to the next digestive organmove food to the next digestive organ. .

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

Howstuffworks "Peristalsis"Howstuffworks "Peristalsis"

1. Peristalsis- 1. Peristalsis- involuntary alternating contractioninvoluntary alternating contraction and relaxation of and relaxation of muscles to squeeze the food through the digestive tract. The muscles to squeeze the food through the digestive tract. The stomach squirts stomach squirts 3 ml or less3 ml or less of chyme into the small intestine at a of chyme into the small intestine at a time.time.

2. Segmentation- single 2. Segmentation- single segments of the intestine alternately segments of the intestine alternately contractcontract and relax. Because active segments are separated the and relax. Because active segments are separated the food is moved forward and then backward. This food is moved forward and then backward. This mixes the foodmixes the food rather than simply propelling through the tract.rather than simply propelling through the tract.

Digestive ProcessDigestive Process

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

1. Activities of the stomach- 1. Activities of the stomach- secreting gastric juicesecreting gastric juice through through sight, smell or taste of food. Two to three liters or gastric juice are sight, smell or taste of food. Two to three liters or gastric juice are

produced a day. Hydrochloric acid is also released in the stomach.produced a day. Hydrochloric acid is also released in the stomach.

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

1. Carbohydrates are broken into 1. Carbohydrates are broken into monosaccharidesmonosaccharides (simple sugars).(simple sugars).

2. Proteins are broken down into 2. Proteins are broken down into amino acidsamino acids. . 3. Lipids are broken down into 3. Lipids are broken down into fatty acids and glycerolfatty acids and glycerol. .

a) Absorption- The a) Absorption- The small intestine is the main site small intestine is the main site where food is absorbedwhere food is absorbed into the blood or lymph. into the blood or lymph.

The The villi play a huge rolevilli play a huge role in the absorption of food. in the absorption of food.b) Defecation- The b) Defecation- The elimination of indigestible elimination of indigestible substancessubstances from the body. This is the job of the from the body. This is the job of the

large large intestines. The “residue” spends about intestines. The “residue” spends about 12 to 14 12 to 14 hourshours in the large intestine as bacteria work to in the large intestine as bacteria work to metabolize metabolize some of the remaining nutrients, some of the remaining nutrients, releasing gases that releasing gases that contribute to the odor of feces. contribute to the odor of feces. You produce about 500 You produce about 500 mL of gas per day!mL of gas per day!

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.

III. Activities occurring through the digestive tractIII. Activities occurring through the digestive tract

Digestion 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 the and to moisten the food to make swallowing and digestion an easier process.food to make swallowing and digestion an easier 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 conscious no longer have conscious controlcontrol and are into the realm of our reflex activity. and are into the realm of our reflex activity.

3. The 3. The epiglottis closes off the tracheaepiglottis closes off the trachea to ensure we do not to ensure we do not choke on our food.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.

B. Activities in the StomachB. Activities in the Stomach

1.1. The food then reaches the stomach The food then reaches the stomach passing through the passing through the cardioesophageal sphinctercardioesophageal sphincter. As the food enters the stomach the . As the food enters the stomach the walls begins to walls begins to stretch and the secretion of gastric juices beginsstretch and the secretion of gastric juices begins. . In addition, the presence of food and falling pH levels in the In addition, the presence of food and falling pH levels in the stomach stimulate the stomach cells to stomach stimulate the stomach cells to secrete the hormone secrete the hormone gastringastrin, prodding the stomach to produce more of the protein-, prodding the stomach to produce more of the protein-digesting enzymes, mucus and hydrochloric acid. digesting enzymes, mucus and hydrochloric acid. 2 to 3 liters2 to 3 liters of of gastric juice are secreted everyday.gastric juice are secreted everyday.

a. Occasionally the cardioesophageal sphincter fails to a. Occasionally the cardioesophageal sphincter fails to close tightly and close tightly and gastric juice backs up in the esophagusgastric juice backs up in the esophagus. This is . This is commonly called commonly called heartburnheartburn. If the acids in the stomach begin . If the acids in the stomach begin digesting the stomach itself this is called an digesting the stomach itself this is called an ulcerulcer. .

2. The 2. The stomach works to compress and pummel the foodstomach works to compress and pummel the food breaking it breaking it apart physically. The chemical digestion of proteins also begins apart physically. The chemical digestion of proteins also begins in the stomach using in the stomach using enzymes called pepsinenzymes called pepsin..

Flashcard Warm-upFlashcard Warm-up

Location of carbohydrate, protein, and Location of carbohydrate, protein, and lipid breakdown by enzymeslipid breakdown by enzymes

Use your notes and book to write down Use your notes and book to write down enzyme names and the location where enzyme names and the location where they are breaking down the food that we they are breaking down the food that we eateat

3.3. Once the food is well mixed a Once the food is well mixed a rippling peristalsis begins inrippling peristalsis begins in the the lower half of the stomach. The lower half of the stomach. The pylorus holds about 30 mLpylorus holds about 30 mL of of chyme, and each contraction squirts only 3 mL through the pyloric chyme, and each contraction squirts only 3 mL through the pyloric sphincter into the small intestine. The emptying of the stomach sphincter into the small intestine. The emptying of the stomach takes about takes about 4 hours after a well-balanced meal4 hours after a well-balanced meal, and , and 6 after a high 6 after a high fat fat meal to empty.meal to empty.

C.C. Activities of the small intestine Activities of the small intestine

1. Once food reaches the small intestine it is only 1. Once food reaches the small intestine it is only partially digested. Carbohydrate and protein digestion has begun partially digested. Carbohydrate and protein digestion has begun but but no fatno fat has been digested at this pointhas been digested at this point. The journey through . The journey through the small intestine will take about the small intestine will take about 3 to 6 hours to complete3 to 6 hours to complete. Food . Food will be moved through the small intestine using will be moved through the small intestine using peristaltic peristaltic contractions and segmented movementscontractions and segmented movements to mix the chyme and to mix the chyme and propel through.propel through.

2. The microvilli of the small intestine have important 2. The microvilli of the small intestine have important enzymes, known as enzymes, known as brush border enzymesbrush border enzymes that break down that break down double sugars into simple sugars and double sugars into simple sugars and complete protein digestioncomplete protein digestion. .

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

4. The two hormones that regulate the release of pancreatic juice into 4. The two hormones that regulate the release of pancreatic juice into the small intestine are the small intestine are secretin and cholecystokininsecretin and cholecystokinin. .

5. 5. 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 globules. large fat globules.

6.6. Absorption of some water and end productsAbsorption of some water and end products then occurs then occurs throughout the passage through the small intestine through the throughout the passage through the small intestine through the villi.villi. At the end of the ileum all that remains is the indigestible At the end of the ileum all that remains is the indigestible

food materials and large amounts of bacteria.food materials and large amounts of bacteria.

D. Activities of the Large IntestineD. Activities of the Large Intestine

1. The food enters the large intestine through the 1. The food enters the large intestine through the ileocecal ileocecal valvevalve. When the residue is delivered here it still has another . When the residue is delivered here it still has another 12-24 12-24 hours to spend therehours to spend there. .

2. The “resident” bacteria then metabolize some of the 2. The “resident” bacteria then metabolize some of the remaining nutrients and remaining nutrients and release gasesrelease gases. .

3. 3. Water is absorbed from the residueWater is absorbed from the residue. . 4. 4. 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 contractions softening the stool and allowing the colon to function properly.softening the stool and allowing the colon to function properly.

5. Watery stools or diarrhea results when 5. Watery stools or diarrhea results when food passes food passes through the large intestine before water can be absorbedthrough the large intestine before water can be absorbed. If food . If food remains in the large intestine for extended periods too much water remains in the large intestine for extended periods too much water is absorbed and the stool becomes difficult to pass. This is called is absorbed and the stool becomes difficult to pass. This is called constipation, usually due to low fiber diets, “failing to heed the call”, constipation, usually due to low fiber diets, “failing to heed the call”, and laxative abuse.and laxative abuse.