The Accessory OrgansThe Accessory Organsof Digestionof Digestion

What is an “Accessory” Organ?What is an “Accessory” Organ?The digestive system has several accessory The digestive system has several accessory organs that aid in the process of digestion. An organs that aid in the process of digestion. An accessory organaccessory organ is one that helps with the is one that helps with the breakdown of food without the food ever breakdown of food without the food ever traveling through them – they are not part of traveling through them – they are not part of the digestive tract or tube.the digestive tract or tube.

The accessory organs of digestion include:The accessory organs of digestion include:1.1. Salivary GlandsSalivary Glands

2.2. LiverLiver

3.3. Gall BladderGall Bladder

4.4. PancreasPancreas

The Salivary GlandsThe Salivary GlandsThe The salivary glandssalivary glands are are small organs found both small organs found both above and below the oral above and below the oral cavity. The secrete a watery cavity. The secrete a watery substance, called substance, called salivasaliva, , that contains both amylase that contains both amylase and mucus.and mucus.AmylaseAmylase is an enzyme that is an enzyme that digests starch – a digests starch – a polysaccharide made of polysaccharide made of many glucose molecules many glucose molecules linked together.linked together.The The mucusmucus is a thicker fluid is a thicker fluid that lubricates the food so it that lubricates the food so it can pass through the can pass through the digestive tube more easily.digestive tube more easily.

The Liver & Gall BladderThe Liver & Gall BladderThe The liverliver is the second largest organ on the body and is the second largest organ on the body and it’s located just below the ribs and to the right. The main it’s located just below the ribs and to the right. The main role of the liver is to produce role of the liver is to produce bilebile – a fluid that aids in the – a fluid that aids in the breakdown of fats.breakdown of fats.The liver also The liver also detoxifiesdetoxifies the blood while leaving the the blood while leaving the nutrients in active circulation.nutrients in active circulation.Alcohol is a toxic substance that the liver breaks apart Alcohol is a toxic substance that the liver breaks apart into less harmful molecules. If too much alcohol is into less harmful molecules. If too much alcohol is consumed on an ongoing basis, the hepatocytes (liver consumed on an ongoing basis, the hepatocytes (liver cells) can die.cells) can die.The The gall bladdergall bladder is a small sac, found just under the is a small sac, found just under the liver, that stores bile.liver, that stores bile.The liver and gall bladder connect to the digestive tract The liver and gall bladder connect to the digestive tract using the using the common bile ductcommon bile duct – a tube that extends down – a tube that extends down into the duodenum - the first part of the small intestine. into the duodenum - the first part of the small intestine.

The Liver & Gall BladderThe Liver & Gall Bladder

The PancreasThe PancreasThe The pancreaspancreas is a bubbly, leaf-shaped organ that lies is a bubbly, leaf-shaped organ that lies just below the stomach. It secretes a great deal of just below the stomach. It secretes a great deal of digestive enzymes – more than any other organ.digestive enzymes – more than any other organ.The pancreas has the pancreatic duct which is a small The pancreas has the pancreatic duct which is a small tube that leads to the first section of the small intestine – tube that leads to the first section of the small intestine – the duodenum. This tube delivers enzymes directly to the duodenum. This tube delivers enzymes directly to the chyme as it travels in the small intestine.the chyme as it travels in the small intestine.The pancreas is responsible for such enzymes as The pancreas is responsible for such enzymes as lipases, carbohydrases and proteases.lipases, carbohydrases and proteases.The pancreas is also an acid-fighting super hero. It The pancreas is also an acid-fighting super hero. It releases a releases a basic solutionbasic solution ( (bicarbonatebicarbonate) into the ) into the duodenum as chyme enters it from the stomach.duodenum as chyme enters it from the stomach.ChymeChyme is the mixture of food and acid that exits the is the mixture of food and acid that exits the stomach. The small intestine and other organs can’t stomach. The small intestine and other organs can’t handle the acidic content in chyme so its acidic handle the acidic content in chyme so its acidic properties are neutralized by the bicarbonate solution.properties are neutralized by the bicarbonate solution.

Chemical DigestionChemical DigestionAmylaseAmylase

PepsinPepsin

TrypsinTrypsin

LipaseLipase

CarbohydraseCarbohydrase

Hydrochloric Acid Hydrochloric Acid (HCl)(HCl)

BileBile

BicarbonateBicarbonate

Starch in mouth and after.Starch in mouth and after.

Proteins in Stomach.Proteins in Stomach.

Proteins in Duodenum (SI).Proteins in Duodenum (SI).

Fats in Duodenum (SI).Fats in Duodenum (SI).

Carbs in Duodenum (SI).Carbs in Duodenum (SI).

All biomolecules in stomach.All biomolecules in stomach.

Emulisfy Fats in Duodenum.Emulisfy Fats in Duodenum.

Neutralize stomach acid found Neutralize stomach acid found in chyme – acts in duodenum.in chyme – acts in duodenum.

Homeostasis & Blood SugarHomeostasis & Blood SugarHomeostasisHomeostasis is the process of maintaining a is the process of maintaining a stable internal environment despite changes in stable internal environment despite changes in the external environment.the external environment.Your body operates under a set of Your body operates under a set of normal normal levelslevels and and rangesranges. These levels and ranges . These levels and ranges apply to everything from body temperature, to apply to everything from body temperature, to heart rate, blood pH and blood sugar. (These heart rate, blood pH and blood sugar. (These are only a few!)are only a few!)If the one of these normal levels strays to far If the one of these normal levels strays to far above or below the normal range – a health above or below the normal range – a health problem (or death!) may ensue.problem (or death!) may ensue.This is why the body uses a system called This is why the body uses a system called negative feedbacknegative feedback to assist in homeostasis. to assist in homeostasis.

Negative FeedbackNegative Feedback

Negative feedbackNegative feedback is a method of maintaining is a method of maintaining homeostasis whereby the system on acts when homeostasis whereby the system on acts when there is a perceived threat to normal body function. there is a perceived threat to normal body function. (“If it ain’t broke – don’t fix it & (“If it ain’t broke – don’t fix it & save energysave energy.”).”)A negative feedback system has three parts:A negative feedback system has three parts:– Monitor Monitor – checks normal levels in body – looks for – checks normal levels in body – looks for

things to be out of the ordinary. (Usually nerve of brain.)things to be out of the ordinary. (Usually nerve of brain.)– Coordinating CentreCoordinating Centre – evaluates threat and brings – evaluates threat and brings

about corrective response. (Usually brain.)about corrective response. (Usually brain.)– RegulatorRegulator – Acts to correct the problem as per direction – Acts to correct the problem as per direction

from coordinating centre. (Organs & Muscles.)from coordinating centre. (Organs & Muscles.)

Your home’s temperature is regulated this way!Your home’s temperature is regulated this way!

Regulating Blood SugarRegulating Blood SugarThe body’s normal level for glucose in the blood The body’s normal level for glucose in the blood (blood sugar) is 4-6mmol/L.(blood sugar) is 4-6mmol/L.If the blood sugar gets too high…If the blood sugar gets too high…– PancreasPancreas produces and secretes produces and secretes insulininsulin into the blood into the blood

stream. This causes cells to adopt glucose from the blood stream. This causes cells to adopt glucose from the blood and helps to lower blood sugar levels.and helps to lower blood sugar levels.

– The The liverliver is told to remove glucose from the blood and is told to remove glucose from the blood and make make glycogenglycogen from it. Again, more sugar withdrawn from it. Again, more sugar withdrawn from the blood and levels go down.from the blood and levels go down.

If the blood sugar gets too low…If the blood sugar gets too low…– The The pancreaspancreas produces and secretes produces and secretes glucagonglucagon which which

goes to the liver and begins the goes to the liver and begins the breakdown of glycogen breakdown of glycogen into glucoseinto glucose which is released into the blood. which is released into the blood.

That’s All I Got…That’s All I Got…