digestive system`. digestive processes ingestion moving food along gi tract mechanical preparation...
TRANSCRIPT
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