DIGESTIVE SYSTEM`

DIGESTIVE PROCESSES

• INGESTION

• MOVING FOOD ALONG GI TRACT

• MECHANICAL PREPARATION FOR DIGESTION

• CHEMICAL DIGESTION

• ABSORPTION

• ELIMINATION

EMBRYONIC DEVELOPMENT

• ECTODERM

• FOREGUT

• HINDGUT

• MIDGUT

• STOMODEUM

• PROCTODEUM

DERIVATIVES OFDIGESTIVE SYSTEM

• GI TRACT

• THYROID

• PARATHYROID

• SALIVARY GLANDS

• LIVER

• GALLBLADDER

• PANCREAS

DIGESTIVE ANATOMY

MUCOUS MEMBRANE

MUCOUS MEMBRANES

ORGANS

• ORAL CAVITY

• PHARYNX

• ESOPHAGUS

• STOMACH

• SMALL INTESTINE

• LARGE INTESTINE

MOUTH

• HARD PALATE

• SOFT PALATE

• UVULA

• GLOSSOPALATINE ARCHES

• PARYNGOPALATINE ARCHES

• FAUCES

ORAL VESTIBULE

ORAL VESTIBULE

LIPS

HARD AND SOFT PALATE

OROPHARYNX

TONGUE

• FLOOR OF MOUTH

• EXTRINSIC MUSCLES

• INTRINSIC MUSCLE

• PAPILLAE

PAPILLAE

• FILIFORM

• FUNGIFORM

• VALLATE

• TASTE BUDS FOUND ON FUNGIFORM AND VALLATE

FILIFORM PAPILLAE

FUNGIFORM PAPILLAE

VALLATE PAPILLAE

LINGUAL TONSILS

• FORMS POSTERIOR DORSAL SURFACE

• LYMPH NODULES

LINGUAL FRENULUM

• CONNECTS TONGUE VENTRALLY

TEETH

• GOMPHOSES IN ALVEOLI

• GINGIVIVAE STRATIFIED SQUAMOUS EPITHELIUM

• PERIDONTAL LIGAMENT

ANATOMY OF THE TOOTH

• DENTIN COVERED BY ENAMEL

• ANCHORED TO PERIDONAL LIGAMENT BY CEMENTUM

PARTS OF TOOTH

• CROWN

• NECK

• ROOT

• PULP CAVITY

• ROOT CANAL

• APICAL FORAMEN

TYPES OF TEETH

• INCISORS

• CUSPIDS

• BICUSPIDS

• MOLARS

DECIDIOUS TEETH

• 20 TEETH

• COME AT REGULAR INTERVALS

• START AT SIX MONTHS

• USUALLY ALL IN BY 2 1/2 YEARS

PERMANENT TEETH

• 32 TEETH

• APPEAR AT ABOUT 6 YEARS

• STOPS AT ABOUT 17 YEARS

• SOMETIME BETWEEN 17 AND 25 WISDOM TEETH MAY COME IN

SALIVARY GLANDS

• BUCCAL GLANDS

• PAROTID GLANDS

• SUBMANDIBULAR GLANDS

• SUBLINGUAL GLANDS

PAROTID GLAND

SUBMANDIBULAR GLAND

SUBLINGUAL SALIVARY GLANDS

PHARYNX

• NASOPHARYNX

• OROPHARYNX

• LARYNGOPHARYNX

MESENTERIES

LAYERS OF THE GASTROINTESTINAL WALL

FOUR LAYERS TUNICA MUSOSA TUNICA SUBMUCOSA TUNICA MUSCULARIS TUNICA SEROSA OR ADVENTITIA

TUNICA MUCOSA

• EPITHELIAL LAYER

• LAMINA PROPIRA

• MUSCULARIS MUCOSAE

EPITHELIAL LAYER

• STRATIFIED SQUAMOUS IN MOUTH ESOPHAGUS AND ANUS

• REST IS SIMPLE COLUMNAR

LAMINA PROPIRA

• LOOSE CONNECTIVE TISSUE CONTAINS BLOOD VESSELS, LYMPH NODULES AND SMALL GLANDS

• PHARYNX -- TONSILS

• SMALL INTESTINE -- PEYERS PATCHES

• APPENDIX -- LYMPH NODULES

MUSCULARIS MUCOSAE

TUNICA SUBMUCOSA

• THICK LAYER OF EITHER DENSE OR LOOSE CONNECTIVE TISSUE

• CONTAINS BLOOD VESSELS, LYMPHATIC VESSELS, NERVES, AND SOMETIMES GLANDS

TUNICA MUSCULARIS

• DOUBLE LAYER OF MUSCLE IN MOST AREAS

• INNER LAYER ARRANGED CIRCULARLY

• OUTER LAYER ARRANGED LONGITUDINALLY

• THICKENED AREAS OF INNER LAYER FORMS SPHINCTERS

MUSCLES FOUND IN MUSCULARIS

• SKELETAL --- UPPER PART OF ESOPHAGUS AND EXTERNAL ANAL SPHINCTER

• SMOOTH -- REST OF TRACT

TUNICA SEROSA OR ADVENTITIA

• OUTER MOST TUNIC

• CONNECTIVE TISSUE

• ESOPHAGUS -- ADVENTITIA

• ABDOMINAL CAVITY COMPONENTS--- SEROSA

NERVE PLEXUSES AND REFLEX PATHWAYS

• SUBMUCOSAL PLEXUS --TUNICA SUBMUCOSA

• MYENTERIC PLEXUS --BETWEEN CIRCULAR AND LONGITUDINAL LAYERS OF TUNICA MUSCLUARIS

• SUBSEROUS PLEXUS -- TUNICA SEROSA

• COORDINATE MUCH OF ACTIVITY OF GI TRACT

GANGLIA FOUND IN GI TRACT

• AUERBACH’S/MYENTERIC PLEXUS– AUTONOMIC GANGLIA ARE FOUND IN THE

TUNICA MUSCULARIS

• MEISSNER’S/SUBMUCOSAL PLEXUS– AUTONOMIC GANGLIA FOUND IN TUNICA

SUBMUCOSA

REFLEX PATHWAYS

• SHORT REFLEXES

• LONG REFLEXES

SHORT REFLEXES

• SIGNALS ORIGINATE FROM RECEPTORS IN WALL OF GI TRACT

• TRANSMITTED BY INTRINSIC NERVE PLEXUS TO EFFECTOR CELLS

• ALL ELEMENTS ARE FOUND IN WALL OF GI TRACT

LONG REFLEXES

• SIGNALS ORIGINATE IN RECEPTORS IN GI TRACT

• TRANSMITTED BY AFFERENT NEURONS TO CNS

• AUTONOMIC NEURONS (VAGUS) CARRY CNS INPUT TO INTRINSIC NERVE PLEXUSES AND EFFECTOR CELLS

ESOPHAGUS

• LONG MUSCULAR TUBE

• POSTERIOR TO TRACHEA

• PASSES THROUGH MEDIASTINUM

• PASSES THROUGH ESOPHAGEAL HIATUS

• PERISTALSIS MOVES FOOD THROUGH

STOMACH

• LEFT OF MID PLANE

• BLOW DIAPHRAGM• CARIDAC ORIFICE• PYLORIC

SPHINCTER

ANATOMY OF STOMACH• LESSER CURVATURE

• GREATER CURVATURE

• LESSER OMENTUM

• GREATER OMENTUM

• FUNDUS

• BODY

• PYLORIC REGION PYLORIC ANTRUM AND CANAL

• RUGAE

STOMACH RUGAE

PYLORIC SPHINCTER

MODIFICATIONS OF STOMACH MUCOSA

• GASTRIC GLANDS IN LAMINA PROPIRA

• GASTRIC PITS

TRANSITION FROM STOMACH TO DUODENUM

TYPES OF GLANDS

• FUNDIC GLANDS

• GASTRIC GLANDS PROPER

• CARDIAC GLANDS

• PYLORIC GLANDS

• ENTEROENDOCRINE CELLS

FUNDIC AND GASTRIC GLANDS PROPER

• MUCOUS NECK CELLS

• PARIETAL (OXYNTIC ) CELLS

• ZYMOGENIC (CHIEF) CELLS

PARIETAL AND CHIEF CELLS

MUCOUS NECK CELLS

• SECRETE MUCOUS

• LOCATED NEAR GASTRIC PITS

PARIETAL CELLS

• OXYNTIC CELLS

• SECRETES HCL

ZYMOGENIC CELLS

• CHIEF CELLS

• SECRETES PEPSINOGEN

CHIEF CELLS

CARDIAC AND PYLORIC GLANDS

• SECRETE MAINLY MUCOUS

ENTEROENDOCRINE CELLS

• GASTRIN

• SEROTONIN

• HISTAMINE

MODIFICATIONS OF TUNICA MUSCULARIS

• OBLIQUE MUSCLE LAYER

• ALLOWS STRONG CONTRACTIONS TO MIX FOOD WITH DIGESTIVE ENZYMES

SMALL INTESTINES

• LONGEST PORTION OF GI TRACT• 6 METERS LONG• MOST CONVOLUTED• LINED WITH SIMPLE COLUMNAR

EPITHELIUM• SPECIALIZED TO ABSORB NUTRIENTS• WHERE MOST ABSORPTION OCCURS

REGIONS OF SMALL INTESTINE

• DUODENUM

• JEJUNUM

• ILEUM

DUODENUM

• HEPATOPANCREATIC AMPULLA (AMPULLA OF VATER)

• DUODENAL PAPILLA

• HEPATOPANCREATIC SPHINCTER (SPHINCTER OF ODDI)

• DUODENUM IS RETROPERITONEAL

• 25 CM

SUBMUCOSA OF DUODENUM

TUNICA MUSCULARIS OF THE DUODENUM

DUODENOJEJUNAL JUNCTION

JEJUNUM

• 2.5 METERS

• SUSPENDED BY MESENTERY

ILEUM

• 3.5 METERS

• ILEOCECAL VALVE

• ILEOCECAL SPHINCTER

• SUSPENDED BY MESENTERY

ILEUM

MODIFICATIONS OF THE SMALL INTESTINE WALL

• OCCUR IN TUNICA MUCOSA AND TUNICA SUBMUCOSA

• PLICAE CIRCULARES

• VILLI

PLICAE CIRCULARES

• CIRCULAR SHELF LIKE FOLDS

• INCREASE SURFACE AREA

• HELP MIX FOOD WITH ENZYMES

VILLI

• MUCOSAL PROJECTIONS INTO LUMEN

• COVERED BY SIMPLE COLUMNAR EPITHELIUM

• CONTAINS A LYMPHATIC CAPILLARY CALLED A LACTEAL

DISTENDED LACTEALS

EPITHELIAL CELLS THAT COVER THE VILLI

• GOBLET CELLS --- MUCUS

• ABSORPTIVE CELLS --- ABSORPTION AND DIGESTION

• ENTEROENDOCRINE CELLS -- IN DUODENUM--CCK, SECRETIN AND OTHERS

ENTEROENDOCRINE CELLS

INTESTINAL GLANDS

• CRYPTS OF LIEBERKUHN

• BETWEEN BASES OF VILLI

PANETH CELLS

• NOT ENTEROENDOCRINE

• SECRETE ANTIBACTERIAL PRODUCTS

PEYER’S PATCHES

• IN SUBMUCOSA

• AGGREGATION OF LYMPHATIC NODULES

LARGE INTESTINE• 1.5 M LONG

• EXTENDS FROM ILEOCECAL VALVE TO ANUS

• NAMED FOR DIAMETER

• SIMPLE COLUMNAR EPITHELIUM

• MICROVILLI

• ABSORPTIVE AND GOBLET CELLS

• FEW ENZYMES PRODUCED

ANATOMY OF THE LARGE INTESTINE

• CECUM

• VERIFORM APPENDIX

• ASCENDING COLON

• RIGHT COLIC (HEPATIC) FLEXURE

• TRANSVERSE COLON

• LEFT COLIC (SPLENIC FLEXURE)

• DESCENDING COLON

• SIGMOID COLON• RECTUM• ANUS

CECUM

• BLIND POUCH

• RECEIVES THE CONTENTS OF THE ILEUM

TYPICAL HISTOLOGY OF THE COLON

VERIFORM APPENDIX

• NARROW BLIND TUBE

• EXTENDS DOWNWARD FROM CECUM

• NUMEROUS LYMPHATIC NODULES

ASCENDING COLON

• EXTENDS UPWARD

• TIGHTLY ATTACHED TO POSTERIOR WALL OF ABDOMEN

• RETROPERITONEAL

RIGHT COLIC FLEXURE

• HEPATIC FLEXURE

• JUST BELOW LIVER

• BENDS TO THE LEFT

TRANSVERSE COLON

• PASSES ACROSS ABDOMINAL CAVITY

• SUPENDED BY MESOCOLON

LEFT COLIC FLEXURE

• SPLENIC FLEXURE

• BENDS DOWNWARD

DESCENDING COLON

• RETROPERITONEAL

• DESCENDS TO LEFT PELVIC BRIM

SIGMOID COLON

• CURVES TO MIDPLANE TO FORM AN S SHAPED SIGMOID COLON

TUNICS OF THE COLON

TUNICA MUCOSA

• INTESTINAL GLANDS

• MUCOUS CELLS

• NO VILLI

• PLICAE SEMILUNARE (SEMILUNAR FOLDS)

TUNICA MUSCULARIS

• TAENIAE COLI

• 3 BANDS OF SMOOTH MUSCLE

• RUNS LENGTH OF COLON

• FORMS POUCHES CALLED HAUSTRA

EPIPLOIC APPENDAGES

• FAT FILLED FOLDS OF PERITONEUM

HAUSTRA

RECTUM

• IN FRONT OF SACRUM

• SAME STRUCTURE AS COLON EXCEPT NO TAENIAE COLI

• FEMALE

MALE RECTUM

ANAL-RECTAL JUNCTION

MUCOUS CUTANEOUS JUNCTIONS

ANAL CANAL

• LAST 3-4 CM OF COLON

• BELOW PELVIC DIAPHRAGM

• NOT IN ABDOMINOPELVIC CAVITY

• MALE ANAL CANAL

ANATOMY OF ANAL CANAL

• ANAL COLUMNS

• ANAL SINUSES

• ANAL VALVES

• INTERNAL AND EXTERNAL ANAL SPHINCTERS

INTERNAL ANAL SPHINCTER

• SMOOTH MUSCLE

EXTERNAL ANAL SPHINCTER

• SKELETAL MUSCLE

• FEMALE

ACCESSORY DIGESTIVE ORGANS

• LOCATED OUTSIDE THE GI TRACT

• IMPORTANT FOR DIGESTION OF FOOD

• CARRIED BY DUCTS

• DERIVED FROM ENDODERM ALSO

PANCREAS

• EXOCRINE AND ENDOCRINE GLAND

• RETROPERITONEAL

• HEAD

• BODY

• TAIL

HEAD OF PANCREAS

BODY OF PANCREAS

TAIL OF PANCREAS

MICROSCOPIC ANATOMY

• RESEMBLE SALIVARY GLANDS

• ACINI

• SINGLE SET OF PYRAMIDAL CELLS

• ACTIVELY SECRETE ZYMOGEN GRANULES

• INACTIVE DIGESTIVE ENZYMES

PANCREATIC SECRETIONS

• HORMONES

• PANCREATIC JUICE

PANCREATIC SECRETIONS

• EXOCRINE

TRANSPORT TO GI TRACT

• PANCREATIC DUCT (DUCT OF WIRSUNG)

• COMMON BILE DUCT

• ACCESSORY PANCREATIC DUCT (DUCT OF SANTORINI)

ENDOCRINE SECRETIONS

• ISLETS OF LANGERHAN

• EXOCYTOSIS

• DIFFUSION INTO BLOOD STREAM

HEAD OF PANCREAS

PANCREAS

AUTONOMIC GANGLION IN PANCREAS

ISLETS OF LANGERHANS

PANCREATIC ACINI

PANCREATIC ACINI

LIVER

• LARGE ORGAN

• MANY IMPORTANT FUNCTIONS

CAUDATE LOBE

QUADRATE LOBE

LEFT LOBE

RIGHT LOBE

FALCIFORM LIGAMENT

LIGAMENTUM TERES

CORONARY LIGAMENT

LIGAMENTUM VENOSUM

BARE AREA

LESSER OMENTUM ATTACHES IT TO STOMACH

BLOOD SUPPLY

• TWO BLOOD SUPPLIES

• 1500 ML OF BLOOD PER MINUTE

• HEPATIC PORTAL VEIN

• SYSTEMIC CIRCULATION

SYSTEMATIC BLOOD SUPPLY

• 400 ML IN HEPATIC ARTERY

• BRANCHES OFF AORTA

• OXYGENATED BLOOD

HEPATIC ARTERY

HEPATIC PORTAL VEIN

• VENOUS BLOOD

• DEOXYGENATED

• NUTRIENT RICH BLOOD FROM DIGESTIVE TRACT, PANCREAS AND SPLEEN

• 1100 ML PER MINUTE

HEPATIC PORTAL VEIN

UNIQUENESS OF HEPATIC CIRCULATION

• BOTH SYSTEMIC ARTERIE AND HEPATIC PORTAL VEIN EMPTY INTO SAME SINUSOIDS

• MEANS THERE IS A MIXTURE OF ARTERIAL AND VENOUS BLOOD

• EMPTY INTO HEPATIC VEIN AND INTO INFERIOR VENA CAVA

STRUCTURE OF THE LIVER

LIVER CORDS OR PLATES

• MADE UP OF ROWS OR SHEETS OF HEPATOCYTES

LIVER LOBULES

• TINY HEXAGONAL COMPARTMENTS

LIVER LOBULES

PORTAL CANALS

• PORTA HEPATIS

HEPATIC TRIAD

CLASSIC LOBULE

CENTRAL VEIN

LIVER STROMA

HEPATOCYTE

LIVER SINUSOIDS

• LINED WITH ENDOTHELIUM

• HIGHLY PERMEABLE

PERISINUSOIDAL SPACE

• SPACE OF DISSE

• SEPARATES THE ENDOTHIAL LINING FROM HEPATOCYTES

• MICROVILLI EXTEN INTO SPACE

STELLATE MACROPHAGES

• KUPPFER CELLS

• EXTENSIONS EXTEND INTO SINUSOIDS

• ACTIVE PHAGOCYTES THAT REMOVE BACTERIA AND FOREIGN CELLS

CELLS LINING SINUSOIDS

BILE CANALICULI

• LOCATED BETWEEN HEPATOCYTES

• CARRY BILE TO BILE DUCTS LOCATED AT PERIPHERY OF LOBULES

• TRAVELS IN OPPOSITE DIRECTION OF BLOOD

• BILE DUCTS JOIN TOGETHER TO FORM HEPATIC DUCT

GLYCOGEN IN THE LIVER

GALL BLADDER

• SMALL SAC ON INFERIOR SURFACE OF LIVER

• COLUMNAR EPITHELIUM

• STORAGE SITE FOR BILE

• SERVICED BY CYSTIC DUCT

HEPATOPANCREATIC SPHINCTER

• CONTROLS FATE OF BILE

COMMON BILE DUCT

• HEPATIC DUCT AND CYSTIC DUCT

GREATER DUODENAL PAPILLAE

LESSER DUODENAL PAPILLAE

COMMON BILE DUCT