Digestive SystemDigestive System

Overview of DigestionOverview of Digestion

2 main groups of organs in the 2 main groups of organs in the digestive system.digestive system.

1. Alimentary Canal (nutrition)1. Alimentary Canal (nutrition) a. Moutha. Mouth b. Pharynxb. Pharynx c. Esophagusc. Esophagus d. Stomachd. Stomach e. Small Intestinee. Small Intestine f. Large Intestinef. Large Intestine

2.2. Accessory Digestive OrgansAccessory Digestive Organs

a. Teetha. Teeth

b. Tongueb. Tongue

c. Gall bladderc. Gall bladder

d. Salivary glandsd. Salivary glands

e. Livere. Liver

f. pancreasf. pancreas

Pharynx and Oral CavityPharynx and Oral Cavity

Superior to the ORAL CAVITY is the Superior to the ORAL CAVITY is the HARD PALATE composed of the HARD PALATE composed of the MAXILLARY and PALATINE bones.MAXILLARY and PALATINE bones.

Superior and posterior to the oral Superior and posterior to the oral cavity are the INTERNAL NARES.cavity are the INTERNAL NARES.

From the internal nares, if we go From the internal nares, if we go anteriorly we will find the anteriorly we will find the EXTERNAL NARES or NOSTRILS.EXTERNAL NARES or NOSTRILS.

Posterior to the hard palate is the SOFT Posterior to the hard palate is the SOFT PALATE. This is muscular tissue that is PALATE. This is muscular tissue that is moved during swallowing.moved during swallowing.

Hanging from the soft palate is a conical Hanging from the soft palate is a conical structure called the UVULA.structure called the UVULA.

The two nasal cavities are separated by The two nasal cavities are separated by the NASAL SEPTUM which is formed by the NASAL SEPTUM which is formed by the union of the VOMER and the union of the VOMER and PERPENDICULAR PLATE of the PERPENDICULAR PLATE of the ETHMOID bones.ETHMOID bones.

3 Areas of the Oral Cavity3 Areas of the Oral Cavity

1.1. OROPHARYNX OROPHARYNX -soft palate to epiglottis-soft palate to epiglottis -two sets of TONSILS-two sets of TONSILS a. Palatinea. Palatine b. Lingualb. Lingual -the tonsils remove pathogens -the tonsils remove pathogens

that enter the pharynx. They that enter the pharynx. They contain lymphocytescontain lymphocytes

2. NASOPHARYNX2. NASOPHARYNX

-located superior and posterior to -located superior and posterior to the soft palate.the soft palate.

-contains the PHARYNGEAL -contains the PHARYNGEAL TONSILS and TUBAL TONSILSTONSILS and TUBAL TONSILS

3. LARYNGOPHARYNX3. LARYNGOPHARYNX

-inferior to the epiglottis and -inferior to the epiglottis and posterior to the larynx.posterior to the larynx.

- this division opens into the - this division opens into the esophagus and larynx.esophagus and larynx.

Sagital section of cadaver head

Notice the nasal conchae. They serve to expand the surface area to warm and moisten breathed air.

Also, notice the position of the spinal cord within the vertebral canal.

How does “Digestion” How does “Digestion” occur?occur?

6 step process:6 step process:

1.1. IngestionIngestion

2.2. PropulsionPropulsion

Peristalsis – alternate waves of Peristalsis – alternate waves of muscular contraction and relaxation muscular contraction and relaxation in the primary digestive organs. The in the primary digestive organs. The end result is to squeeze food from end result is to squeeze food from one part of the system to the next.one part of the system to the next.

3.3. Mechanical DigestionMechanical Digestion

- physical preparation of food for - physical preparation of food for digestion.digestion.

- Segmentation – mixing of food in - Segmentation – mixing of food in the intestines with digestive juices.the intestines with digestive juices.

4.4. Chemical DigestionChemical Digestion

- Carbohydrates, Fat, and Proteins - Carbohydrates, Fat, and Proteins are broken down by enzymes.are broken down by enzymes.

5.5. AbsorptionAbsorption

- transfer of the digested portion - transfer of the digested portion of food into the blood from the of food into the blood from the digestive canal.digestive canal.

6.6. DefecationDefecation

- removal/elimination of the waste - removal/elimination of the waste products from the body. products from the body.

Histology of the Histology of the Digestive SystemDigestive System

All alimentary canal organs have the All alimentary canal organs have the same 4 layers.same 4 layers.

1.1. Mucosa (innermost layer)Mucosa (innermost layer)

2.2. Submucosa (CT containing Submucosa (CT containing neurovascular bundles)neurovascular bundles)

3.3. Muscularis Externa (2 layers of Muscularis Externa (2 layers of smooth muscle)smooth muscle)

4.4. Serosa (outermost layer, visceral Serosa (outermost layer, visceral peritoneum)peritoneum)

Diagram of GI wall to show various kinds of glands -- some within the wall and some without (like the liver). These glands have ducts that empty into the lumen of the gut. In all cases, the epithelium lining the ducts and glands is continuous with the epithelium lining the lumen (cavity) of the gut.

The image above shows a section of colon from a dog. Note the crypts extending from the lumen, and the numerous, foamy goblet cells that populate the epithelium of the crypts.

Secretion of mucus from goblet cells is elicited primarily by irritating stimuli rather than in response to hormones

Mouth and Associated Mouth and Associated OrgansOrgans

Food enters the GI tract at the mouth. Food enters the GI tract at the mouth. It is chewed, manipulated by the It is chewed, manipulated by the tongue, and moistened with saliva.tongue, and moistened with saliva.

Mouth has two parts:Mouth has two parts:

1. vestibule – space between cheek 1. vestibule – space between cheek and teeth.and teeth.

2. oral cavity proper – space 2. oral cavity proper – space internal to the teeth.internal to the teeth.

TongueTongue

- skeletal muscle- skeletal muscle

- mixes food with saliva into a - mixes food with saliva into a compact mass known as a BOLUS.compact mass known as a BOLUS.

- LINGUAL FRENULUM attaches - LINGUAL FRENULUM attaches the tongue to the floor of the mouth the tongue to the floor of the mouth and prevents posterior movement of and prevents posterior movement of the tongue.the tongue.

Salivary GlandsSalivary Glands

When you dissect your cat, you will When you dissect your cat, you will notice two muscles on the inside of notice two muscles on the inside of the cheek.the cheek.

The DIGASTRIC MUSCLE opens the The DIGASTRIC MUSCLE opens the jaw.jaw.

The MASSETER MUSCLE closes the The MASSETER MUSCLE closes the jaw.jaw.

The masseter inserts on the The masseter inserts on the mandible.mandible.

Superficial to part of the masseter Superficial to part of the masseter and anterior to the ear is the large and anterior to the ear is the large PAROTID GLAND. This gland PAROTID GLAND. This gland produces SALIVARY AMYLASE produces SALIVARY AMYLASE (ptyalin), a digestive enzyme.(ptyalin), a digestive enzyme.

The parotid gland is GRANULAR, it The parotid gland is GRANULAR, it is attached by fascia. It is also the is attached by fascia. It is also the largest of the salivary glands.largest of the salivary glands.

The parotid empties into the PAROTID The parotid empties into the PAROTID DUCT which empties between the last two DUCT which empties between the last two molars at the angle of the jaw.molars at the angle of the jaw.

The parotid gland is an EXOCRINE The parotid gland is an EXOCRINE GLAND. Exocrine glands empty via a GLAND. Exocrine glands empty via a duct to a specific location. The other type duct to a specific location. The other type of gland is an ENDOCRINE GLAND that of gland is an ENDOCRINE GLAND that empties directly into the bloodstream.empties directly into the bloodstream.

Caudal and ventral to the parotid Caudal and ventral to the parotid gland is the SUBMANDIBULAR gland is the SUBMANDIBULAR GLAND (SUBMAXILLARY).GLAND (SUBMAXILLARY).

The SUBMAXILLARY DUCT empties The SUBMAXILLARY DUCT empties this gland. It runs on the lateral this gland. It runs on the lateral aspect of the digastric muscle.aspect of the digastric muscle.

This gland carries saliva into the This gland carries saliva into the angle of the lower jaw.angle of the lower jaw.

The SUBLINGUAL GLAND is on the The SUBLINGUAL GLAND is on the submaxillary duct. It is wedge shaped submaxillary duct. It is wedge shaped and it is lateral to the digastric muscle.and it is lateral to the digastric muscle.

The DORSAL and VENTRAL FACIAL The DORSAL and VENTRAL FACIAL NERVES run around the outline of the NERVES run around the outline of the masseter muscle. These nerves come out masseter muscle. These nerves come out in front of the ear from the in front of the ear from the STYLOMASTOID FORAMEN and branch STYLOMASTOID FORAMEN and branch across the face.across the face.

1. Masseter Muscle

2. Parotid Gland

3. Parotid Duct

4. Submandibular Gland

5. Sublingual Gland

6. Lymph Nodes

7. Molar Gland

Parotid gland

Submandibular gland

Sublingual gland

Parotid Duct

Submandibular Duct

Masseter muscle

5 Openings into the 5 Openings into the PharynxPharynx

1.1. MouthMouth

2.2. Left and right nasal passagesLeft and right nasal passages

3.3. Eustachian tubes (connect middle Eustachian tubes (connect middle ear to the throat)ear to the throat)

4.4. LarynxLarynx

5.5. EsophagusEsophagus

SwallowingSwallowing Is a reflex.Is a reflex. When the mouth closes, the When the mouth closes, the

soft palate is pushed soft palate is pushed superiorly and closes the superiorly and closes the nasal passagesnasal passages

A sphincter valve closes off A sphincter valve closes off the eustachian tubesthe eustachian tubes

The glottis closes and The glottis closes and respiration stops. The respiration stops. The glottis also bends and closes glottis also bends and closes the entrance into the larynx.the entrance into the larynx.

The esophagus is opened by The esophagus is opened by pressure of the food. This pressure of the food. This allows the epiglottis to open.allows the epiglottis to open.

Food then enters the Food then enters the esophagus.esophagus.

TeethTeeth

Very similar to bone.Very similar to bone. Three major components:Three major components:

1. hydroxyapatite Ca1. hydroxyapatite Ca55(PO(PO44))33(OH)(OH)

2. bone collagen2. bone collagen

3. cells3. cells

The pH of the mouth is usually 7.2The pH of the mouth is usually 7.2 There are acids in the mouth that There are acids in the mouth that

come from three sources:come from three sources:

1. stomach acid during vomiting1. stomach acid during vomiting

2. foods2. foods

3. waste products of mouth 3. waste products of mouth bacteriabacteria

Tooth AnatomyTooth Anatomy Enamel: hardest substance in the bodyEnamel: hardest substance in the body Pulp Cavity: contains arteries, veins, and Pulp Cavity: contains arteries, veins, and

nerves.nerves. Alveolus: made of alveolar boneAlveolus: made of alveolar bone Root: made of dentinRoot: made of dentin Gingiva: gumGingiva: gum Periodontal membrane: periosteum found Periodontal membrane: periosteum found

around the tootharound the tooth Cementum: material that holds the tooth Cementum: material that holds the tooth

in the alveolus.in the alveolus.

INCISORS – chisel shaped for INCISORS – chisel shaped for nipping food.nipping food.

CANINES – cone shaped for tearingCANINES – cone shaped for tearing PREMOLARS – PREMOLARS – MOLARS - grinding foodMOLARS - grinding food

32 teeth in the Permanent Dentition32 teeth in the Permanent Dentition 20 teeth in the Deciduous Dentition20 teeth in the Deciduous Dentition

Identify the Following:

Incisors

Molar

Premolars

Canines

The Digestive SystemThe Digestive System

Function: physically and chemically Function: physically and chemically breakdown food products so that they can breakdown food products so that they can be absorbed and transported to cells.be absorbed and transported to cells.

CARBOHYDRATES are the major source CARBOHYDRATES are the major source of biochemical energy. They include of biochemical energy. They include sugars and starches. These are sugars and starches. These are eventually broken down into eventually broken down into MONOSACCHARIDES (simple sugars)MONOSACCHARIDES (simple sugars)

PROTEINS are broken down to amino acids. PROTEINS are broken down to amino acids. AMINO ACIDS are the chemical building blocks AMINO ACIDS are the chemical building blocks of proteins. Proteins are necessary parts of cell of proteins. Proteins are necessary parts of cell membranes and nucleic acids (DNA and RNA).membranes and nucleic acids (DNA and RNA).

LIPIDS are broken down to fatty acids and LIPIDS are broken down to fatty acids and glycerol. Lipids are very large molecules and glycerol. Lipids are very large molecules and cannot be directly absorbed. They are broken cannot be directly absorbed. They are broken down by ENZYMES which are organic down by ENZYMES which are organic CATALYSTS. They are very specific for each CATALYSTS. They are very specific for each chemical reaction and the function to speed up chemical reaction and the function to speed up the reaction.the reaction.

The name of an enzyme usually end The name of an enzyme usually end in “-ase” and can give a clue as to its in “-ase” and can give a clue as to its function.function.

For example, Lipase is an enzyme For example, Lipase is an enzyme that catalyzes the breakdown of that catalyzes the breakdown of lipids (fats and oils)lipids (fats and oils)

Chewing (Mastication)Chewing (Mastication)

Helps the digestive process by:Helps the digestive process by:

a. Mixes food with digestive a. Mixes food with digestive enzymes in saliva.enzymes in saliva.

b. Increases surfaces area of food b. Increases surfaces area of food

c. Makes moving the food easierc. Makes moving the food easier

SalivaSaliva

Contains PTYALIN or SALIVARY Contains PTYALIN or SALIVARY AMYLASE. These are enzymes that AMYLASE. These are enzymes that break down starches. These break down starches. These enzymes are only active under enzymes are only active under certain pH conditions.certain pH conditions.

The pH of the mouth is about 7.2 The pH of the mouth is about 7.2 (slightly alkaline as 7 directly in the (slightly alkaline as 7 directly in the middle of the scale)middle of the scale)

When the swallowed food reaches When the swallowed food reaches the stomach, the pH drops to 3 (very the stomach, the pH drops to 3 (very acidic). The ptyalin is no longer acidic). The ptyalin is no longer active at that pH.active at that pH.

Once food is swallowed, smooth Once food is swallowed, smooth muscle in the esophagus carries the muscle in the esophagus carries the bolus by PERISTALSIS.bolus by PERISTALSIS.

Once food enters the esophagus, Once food enters the esophagus, peristalsis is automatic. In fact, food peristalsis is automatic. In fact, food can successfully reach the stomach can successfully reach the stomach while standing on your hands.while standing on your hands.

The bolus enters the stomach by The bolus enters the stomach by passing through the passing through the GASTROESOPHAGEAL SPHINCTER. GASTROESOPHAGEAL SPHINCTER. It is held shut by contraction of It is held shut by contraction of muscle.muscle.

1. Diaphragm 7. Right Medial Lobe of Liver

2. Round Ligament 8. Right Lateral Lobe of Liver

3. Falciform Ligament 9. Gall Bladder

4. Left Lateral Lobe of Liver 10. Spleen

5. Left Medial Lobe of Liver 11. Greater Omentum

6. Quadrate Lobe of Liver

esophagusGastroesophageal sphincter

Fundus

Body

Pylorus

Pyloric shpincter

esophagus GES

stomach

The LESSER CURVATURE of the The LESSER CURVATURE of the stomach is anchored to the liver with stomach is anchored to the liver with the LESSER OMENTUM. It cannot the LESSER OMENTUM. It cannot move.move.

The esophagus and duodenal ends The esophagus and duodenal ends are anchored. As food fills the are anchored. As food fills the stomach, it can sag on the left side.stomach, it can sag on the left side.

The walls of the stomach have 3 muscle The walls of the stomach have 3 muscle layerslayers

These muscles do not contract together-These muscles do not contract together-they contract out of sync. This enables they contract out of sync. This enables the muscles to mix and churn the food in the muscles to mix and churn the food in the body of the stomach.the body of the stomach.

The mixing is with water, hydrochloric The mixing is with water, hydrochloric acid (produced in the stomach), and acid (produced in the stomach), and pepsin. This mixture is known as CHYME.pepsin. This mixture is known as CHYME.

The release of the chyme is The release of the chyme is regulated by the pyloric sphincter.regulated by the pyloric sphincter.

The stomach also has longitudinal The stomach also has longitudinal folds within the lumen. These folds, folds within the lumen. These folds, called RUGAE, increase the surface called RUGAE, increase the surface area of the stomach.area of the stomach.

Small IntestineSmall Intestine

3 parts:3 parts: 1. Duodenum1. Duodenum - 10 inches long- 10 inches long 2. Jejunum2. Jejunum - 8 feet long- 8 feet long 3. Ileum3. Ileum - 11 feet long- 11 feet long

mesentery

The small intestine produces 7 The small intestine produces 7 enzymes. There are a total of 17 enzymes. There are a total of 17 enzymes that are dumped into the enzymes that are dumped into the duodenum for digestion.duodenum for digestion.

The small intestine is the area where The small intestine is the area where most digestion occurs.most digestion occurs.

It is also the place where 74% of the It is also the place where 74% of the absorption of nutrients occur.absorption of nutrients occur.

The absorptive area is increased by:The absorptive area is increased by: 1. circular folds called PLICAE 1. circular folds called PLICAE

CIRCULARIS.CIRCULARIS. 2. Microscopic VILLI2. Microscopic VILLI 3. MICROVILLI3. MICROVILLIThese structures increase the surface These structures increase the surface

area of the small intestine by 600xarea of the small intestine by 600x

Within the plicae circularis are arteries, Within the plicae circularis are arteries, capillaries, and veins. The veins drain capillaries, and veins. The veins drain into the HEPATIC PORTAL SYSTEM into the HEPATIC PORTAL SYSTEM which ultimately drain into the liver and which ultimately drain into the liver and INFERIOR VENA CAVA.INFERIOR VENA CAVA.

There is also lymphatic drainage via There is also lymphatic drainage via LACTEALS which drain into the LACTEALS which drain into the CISTERNA CHYLI. These drain into the CISTERNA CHYLI. These drain into the THORACIC DUCT.THORACIC DUCT.

SEGMENTAL PERISTLASIS occurs SEGMENTAL PERISTLASIS occurs in the small intestine. This in the small intestine. This segmenting results in a sausage segmenting results in a sausage appearing structure.appearing structure.

The ileocecal valve (sphincter) The ileocecal valve (sphincter) regulates flow into to large intestine. regulates flow into to large intestine. It also prevents backflow from the It also prevents backflow from the large intestine into the small large intestine into the small intestine.intestine.

Sources of Intestinal Sources of Intestinal SecretionsSecretions

Stomach

Spleen

pancreas

Duodenum

Jejunum

Esophagus

Cystic Duct Hepatic Ducts

Common Bile DuctGall

Bladder

villi

microvilli

1. Cardiac Stomach 8. Ascending Colon

2. Fundic Stomach 9. Ileum

3. Stomach Body 10. Jejunum

4. Pyloric Stomach 11. Sigmoid Colon

5. Lesser Omentum 12. Spleen

6. Duodenum 13. Gastrospleenic Ligament

7. Pancreas (Ventral) 14. Bladder

The Large IntestineThe Large Intestine

5 feet long5 feet long The CECUM extends as a 2.5 inch The CECUM extends as a 2.5 inch

blind sac caudally from the blind sac caudally from the sphincter.sphincter.

Off the cecum is the APPENDIX. Off the cecum is the APPENDIX. There is currently no purpose for the There is currently no purpose for the appendix. Some research is pointing appendix. Some research is pointing toward an immune function.toward an immune function.

From the cecum is the ASCENDING From the cecum is the ASCENDING COLON (5 inches). It is COLON (5 inches). It is retroperitoneal.retroperitoneal.

The RIGHT COLIC FLEXURE leads The RIGHT COLIC FLEXURE leads to the TRNASVERSE COLON (15 to the TRNASVERSE COLON (15 inches). inches).

The LEFT COLIC FLEXURE leads to The LEFT COLIC FLEXURE leads to the DESCENDING COLON (10 the DESCENDING COLON (10 inches) and it is also retroperitoneal.inches) and it is also retroperitoneal.

The descending colon leads to the The descending colon leads to the SIGMOID COLON. The name change SIGMOID COLON. The name change occurs at the SIGMOID FLEXURE.occurs at the SIGMOID FLEXURE.

The RECTUM (5 inches) leads to the The RECTUM (5 inches) leads to the ANAL CANAL (7 inches).ANAL CANAL (7 inches).

The final sphincter in the tract is the The final sphincter in the tract is the SPHINCTER ANI.SPHINCTER ANI.

The sigmoid and rectum are also The sigmoid and rectum are also retroperitoneal.retroperitoneal.

The transverse colon hands on a piece of The transverse colon hands on a piece of the MESOCOLIC LIGAMENT.the MESOCOLIC LIGAMENT.

It hangs into the umbilical region.It hangs into the umbilical region. The longitudinal bands of muscle in the The longitudinal bands of muscle in the

colon are three bands that do not colon are three bands that do not completely surround the structure.completely surround the structure.

The only part of the large intestine that The only part of the large intestine that have complete muscle coverage is the have complete muscle coverage is the rectum.rectum.

Liver esophagus

Fundus of Stomach

Gastroesophageal sphincter

Pylorus of stomach

Gall bladder

Parotid Gland

pancreas

cecum

The muscles act like a drawstring that The muscles act like a drawstring that contract the colon into little pouches. contract the colon into little pouches. These pouches are called HAUSTRA.These pouches are called HAUSTRA.

The material that reaches the colon is The material that reaches the colon is undigested and/or undigestable.undigested and/or undigestable.

Bacteria live in the colon. These are Bacteria live in the colon. These are important for the synthesis of Vit. B12 and important for the synthesis of Vit. B12 and K. Other bacteria are responsible for K. Other bacteria are responsible for destroying the “bad” bacteria.destroying the “bad” bacteria.

E. coli is an exampleE. coli is an example

The sphincter ani is an involuntary smooth The sphincter ani is an involuntary smooth muscle.muscle.

The DEFECATION REFLEX which is kept in The DEFECATION REFLEX which is kept in control by the sigmoid flexure and peristaltic control by the sigmoid flexure and peristaltic activity.activity.

When peristalsis occurs the sphincter ani When peristalsis occurs the sphincter ani relaxes. An EXTERNAL SPHINCTER (skeletal relaxes. An EXTERNAL SPHINCTER (skeletal muscle) can oppose the sphincter ani. This muscle) can oppose the sphincter ani. This allows you to “hold it in” until you find a allows you to “hold it in” until you find a bathroom!bathroom!

The first part and part of the second third of the The first part and part of the second third of the esophagus are also made of skeletal muscle. The esophagus are also made of skeletal muscle. The rest of the GI tract is smooth muscle.rest of the GI tract is smooth muscle.

Anal Canal

rectum

Sigmoid colon

Descending Colon

Haustra

Terminal Ileum

cecum

appendix

Transverse Colon

Ascending colon

Tenia coli

1. Small Intestine 6. Transverse Colon

2. THE Mesentary 7. Descending Colon

3. Ileum 8. Sigmoid Colon

4. Cecum 9. Mesocolon

5. Ascending Colon 10. Greater Omentum

Types of Hernia

Some DefinitionsSome Definitions

SecretionSecretion

- discharge of materials synthesized by - discharge of materials synthesized by cells.cells.

ExcretionExcretion

- discharge of metabolic waste products - discharge of metabolic waste products from our cells. Occurs at skin, sweat from our cells. Occurs at skin, sweat glands, lungs, feces, and kidneys.glands, lungs, feces, and kidneys.

LiverLiver 5 functions:5 functions: 1. 1. Detoxification of bloodDetoxification of blood2. Carbohydrate metabolism2. Carbohydrate metabolism -glycogenesis – formation of glycogen from excess glucose in -glycogenesis – formation of glycogen from excess glucose in circulation.circulation. -glycogenolysis – breakdown of glycogen in times of fasting.-glycogenolysis – breakdown of glycogen in times of fasting. -gluconeogenesis-formation of glucose in hepatocytes from raw -gluconeogenesis-formation of glucose in hepatocytes from raw materials.materials.3. Lipid metabolism3. Lipid metabolism -synthesizes large quantities of cholesterol and phospholipids.-synthesizes large quantities of cholesterol and phospholipids. -oxidizing triglycerides to produce energy. -oxidizing triglycerides to produce energy. 4. Protein synthesis4. Protein synthesis5. Secretion of bile5. Secretion of bile

Bile contains bile salts, water, Bile contains bile salts, water, pigments, cholesterol, and lecithin (a pigments, cholesterol, and lecithin (a phospholipid)phospholipid)

Bile salts act like detergents and Bile salts act like detergents and EMULSIFY fats. Makes fat form into EMULSIFY fats. Makes fat form into small droplets that are more soluble. small droplets that are more soluble. Greater surface area makes it more Greater surface area makes it more digestible.digestible.

Bile is stored in the GALL BLADDER Bile is stored in the GALL BLADDER where it is concentrated. When fat is where it is concentrated. When fat is detected in the duodenum, the gall detected in the duodenum, the gall bladder contracts and bile is discharged bladder contracts and bile is discharged into it.into it.

The COMMON BILE DUCT comes into the The COMMON BILE DUCT comes into the first inch of the duodenum. Its opening is first inch of the duodenum. Its opening is called the AMPULLA OF VATER. This called the AMPULLA OF VATER. This opening is controlled by the SPHINCTER opening is controlled by the SPHINCTER OF ODDI. This sphincter relaxes when OF ODDI. This sphincter relaxes when the gall bladder contracts.the gall bladder contracts.

PancreasPancreas Produces approx. 10 enzymes which are Produces approx. 10 enzymes which are

responsible for digestion.responsible for digestion. The PANCREATIC DUCT carries these The PANCREATIC DUCT carries these

enzymes directly into the common bile enzymes directly into the common bile duct. Sometimes it empties directly into duct. Sometimes it empties directly into the duodenum (anatomic variance).the duodenum (anatomic variance).

Also secretes BICARBONATE which Also secretes BICARBONATE which neutralizes the duodenal contents.neutralizes the duodenal contents.

The ISLETS OF LANGERHANS produce The ISLETS OF LANGERHANS produce INSULIN and GLUCAGON.INSULIN and GLUCAGON.

SpleenSpleen

Stores bloodStores blood Produces WBCProduces WBC Part of lymphatic systemPart of lymphatic system Found midaxillary, deep to ribs 9-11 Found midaxillary, deep to ribs 9-11

and superior to the TPL.and superior to the TPL.