Lecture Notes Menu Digestive System

I. OVERVIEW OF THE DIGESTIVE SYSTEM

  1. THE DIGESTIVE SYSTEM CONSISTS OF THE FOLLOWING :

    1. ORAL CAVITY

    2. PHARYNX

    3. ESOPHAGUS

    4. STOMACH

    5. SMALL INTESTINE

    6. LARGE INTESTINE

    7. ANUS

  2. THE ACCESSORY ORGANS INCLUDE :

    1. SALIVARY GLANDS

    2. LIVER

    3. GALL BLADDER

    4. PANCREAS

  3. THE G.I. TRACT CONSISTS OF FOUR LAYERS OR TUNICS :
    1. MUCOSAL
    2. SUBMUCOSA
    3. MUSCULARIS
    4. ADVENTITIA

  4. THE MUCOSAL LAYER IS THE INNERMOST LAYER, IT CONSISTS OF
    1. MUCOUS EPITHELIUM :

      LOCATION TYPE
      MOUTH, OROPHARYNX, ESOPHAGUS, ANUS STRATIFIED
      SQUAMOUS
      REMAINDER OF THE G.I. TRACT SIMPLE
      COLUMNAR


    2. LOOSE CONNECTIVE ( LAMINA PROPRIA )

    3. THIN MUSCLE LAYER ( MUSCULARIS MUCOSA )

  5. SUBMUCOSA IS A THICK LAYER THAT CONSISTS OF :

    1. CONNECTIVE TISSUE

    2. NERVES

    3. BLOOD VESSELS

    4. SMALL GLANDS

    5. PLEXUS ( PARASYMPATHETIC NERVES )

  6. THE MUSCULARIS LAYER CONSISTS OF : STOMACH OBLIQUE LAYER

    1. INNER CIRCULAR SMOOTH MUSCLE

    2. OUTER LONGITUDINAL SMOOTH MUSCLE

    3. EXCEPTIONS : UPPER ESOPHAGUS ( STRIATED ) AND STOMACH

    4. PLEXUS ( NERVE FIBERS AND PARASYMPATHETIC CELL BODIES (LOCATED BETWEEN TWO MUSCLE LAYERS

  7. SEROSA - OUTER LAYER - SEROUS EPITHELIUM

  8. PERITONEUM

    1. SIMPLE SQUAMOUS WITH CONNECTIVE TISSUES

    2. SEROUS

    3. VISCERAL PERITONIEUM (ORGANS SEROSA)

    4. SPACE BETWEEN PARIETAL AND VISCERAL POTENTIAL SPACE- FLUID FILLED ASCITES (A- SI- TEZ) LARGE ACC. FLUID

    5. MESENTERY- FOLDS BETWEEN ORGANS

    6. MESOCOLON- BINDS L.I. TO POSTERIOR WALL

    7. FALSIFORM LIGAMENT

    8. LESER AND GREATER OMENTUM (FATTY APRON)

    9. KIDNEY- PANCREAS- RETRO PERITONEAL

II. GENERAL STRUCTURES OF ORGANS
  1. ORAL CAVITY

    1. LIPS AND CHEEKS ARE INVOLVED IN FACIAL EXPRESSION , MASTICATION AND SPEECH

    2. THE TONGUE IS INVOLVED WITH SPEECH, TASTE, MASTICATION AND SWALLOWING.

    3. THERE ARE 20 DECIDUOUS TEETH AND 32 PERMANENT TEETH

      1. TOOTH TYPES ARE :

        MOLARS
        CANINE
        PRE MOLARS
        INCISORS

      2. A TOOTH CONSISTS OF A :

        CROWN
        NECK
        ROOT

      3. COMPONENTS OF THE TOOTH INCLUDE:

        DENTIN
        PULP CAVITY ( NERVES, BLOOD VESSELS )
        CROWN

      4. TEETH ARE HELD IN THE ALVEOLI BY PERIDONTAL LIGAMENTS

        THE MUSCLES MASTICATION INCLUDE :

        MASSETER
        TEMPORAL
        MEDIAL PTERYGOID
        LATERAL PTERYGOID

        ROOF OF THE PALATE IS DIVIDED INTO THE HARD AND SOFT ALSO FOUND ARE THE UVULA AND FRENULUM

        SALIVARY GLANDS PRODUCE SEROUS AND MUCOSAL SECRETIONS

        THREE GLANDS ARE :

        PAROTID
        SUBMANDIBULAR
        SUBLINGUAL

        TONSILS INCLUDE : PHARYNGEAL, PALATINE, LINGUAL

        THE PHARYNX INCLUDES :

        NASOPHARYNX, OROPHARYNX, AND LARYNGOPHARYNX


      5. ESOPHAGUS

        1. THE ESOPHAGUS CONNECTS THE PHARYNX TO THE STOMACH

        2. THE UPPER AND LOWER ESOPHOGEAL SPINCTERS REGULATE MOVEMENT IN THE ESOPHAGUS

        3. THE ESOPHAGUS CONSISTS OF FOUR LAYERS

          FIBROUS LAYER - OUTER
          MUSCULAR LAYER - CIRCULAR AND LONGITUDINAL
          SUBMUCOSAL
          STRATIFIED SQUAMOUS EPITHELIUM

        4. THE ESOPHAGUS IS APP. 25 CM LONG, POSITION IS AS FOLLOWS

        5. LIES IN THE MEDIASTINUM

        6. ANTERIOR TO VERTEBRA

        7. POSTERIOR TO THE TRACHEA

        8. PASSES THROUGH THE ESOPHAGEAL HIATUS - OPENING

      6. STOMACH

        1. STRUCTURES OF THE STOMACH INCLUDE :

          1. OPENING INTO THE ESOPHAGUS (GASTROESOPHAGEAL) - CARDIAC

          2. OPENING INTO THE DUODENUM ( PYLORIC )

        2. THE WALL OF THE STOMACH INCLUDES :

          1. EXTERNAL SEROSA

          2. MUSCLE LAYER ( CIRCULAR, LONGITUDINAL, OBLIQUE )

          3. SUBMUCOSA

          4. SIMPLE COLUMNAR ( INTERIOR MUCOSAL )

        3. RUGAE ARE THE FOLDS IN THE STOMACH WHEN EMPTY

        4. GASTRIC PITS ARE THE OPENINGS INTO THE GASTRIC GLANDS

          1. . MUCOSAL NECK CELLS- MUCUS

          2. PARIETAL CELLS- HCL

          3. CHIEF CELLS- ZYMOGENIC- PEPSINOGEN

          4. ENDOCRINE CELLS

        5. GROSS ANATOMY OF THE STOMACH INCLUDE :

          1. FUNDUS

          2. CARDIAC REGION

          3. GREATER CURVATURE

          4. LESSER CURVATURE

          5. PYLORIC ANTRUM

          6. PYLORIC CANAL

          7. G. PYLORIC ORIFICE

      7. SMALL INTESTINE

        1. DIVIDED INTO THREE PORTIONS : TOTAL 20FT IN LENGTH

          1. DUODENUM- 10 INCHES

          2. JEJUNUM- 2/5

          3. ILEUM- 3/5

        2. THE WALL OF THE SMALL INTESTINE INCLUDES :

          1. EXTERNAL SEROSA

          2. MUSCULAR ( LONGITUDINAL, CIRCULAR )

          3. SUBMUCOSA

          4. SIMPLE COLUMNAR EPITHELIUM ( MUCOSAL )

        3. VILLI AND MICROVILLI INCREASE SURFACE AREA

        4. ABSORPTIVE, GOBLET, AND ENDOCRINE CELLS DEVELOP IN INTESTINAL GLANDS, CRYPTS OF LIEBERKUHN SECRETE DIGESTIVE ENZYME

        5. DUODENAL GLANDS PRODUCE MUCUS

        6. THE MUCOSA OF THE DUODENUM IS SIMPLE COLUMNAR OF THREE TYPES :

          1. ABSORPTIVE CELLS ( MICROVILLI )

          2. GOBLET CELLS ( PRODUCE MUCUS )

          3. ENDOCRINE CELLS ( REGULATORY HORMONES )

        7. THE SUBMUCOSA CONTAIN CELLS CALLED : BRUNNERS GLANDS THESE CELLS PRODUCE MUCUS

        8. STRUCTURE OF THE DUODENUM :

          1. CONTAINS A 180 DEGREE ARC

          2. GREATER AND LESSER DUODENAL PAPILLA GREATER : BILE AND PANCREATIC DUCTS JOIN THIS FORMS THE HEPATOPANCREATIC AMPULLA OPENING: HEPATOPANCREATIC AMPULLAR SPINCTER

          3. ACCESSORY PANCREATIC DUCT IS PRESENT IN MOST PEOPLE, FOUND AT LESSER PAPILLA

        9. THE JEJUNUM AND ILEUM ARE SIMILAR IN STRUCTURE TO THE DUODENUM, EXCEPT :

          1. GRADUAL DECREASE IN DIAMETER

          2. DECREASE IN THICKNESS

          3. DECREASE IN FOLDS AND VILLI

        10. THE JEJUNUM AND ILEUM ARE THE SITE OF MOST NUTRIENT ABSORPTION

        11. THE JUNCTION BETWEEN THE ILEUM AND THE LARGE INTESTINE IS THE ILEOCECAL JUNCTION ( SPHINCTER )

      8. LIVER

        1. THE LIVER IS THE LARGEST INTERNAL ORGAN OF THE BODY

        2. LOCATED IN THE RIGHT HYPOCHONDRIATIC AREA

        3. THE LIVER CONSISTS OF TWO MAJOR LOBES : LEFT AND RIGHT

        4. TWO MINOR LOBES : CAUDATE (RIGHT LOBE) AND QUADRATE

          A PORTA IS ON THE INFERIOR SURFACE OF THE LIVER, THIS IS THE AREA MANY BLOOD VESSELS, NERVES, AND DUCTS ENTER THE LIVER

        5. STRUCTURES AROUND THE PORTA INCLUDE :

          HEPATIC PORTAL VEIN
          HEPATIC ARTERY
          NERVE PLEXUS
          LYMPHATIC VESSELS
          TWO HEPATIC DUCTS ( TRANSPORT BILE )

        6. BRANCHING OF DUCTS INCLUDE :

          HEPATIC DUCTS ( 2 )
          COMMON HEPATIC DUCT
          CYSTIC DUCT ( FROM GALL BLADDER )
          COMMON BILE DUCT ( EMPTIES INTO DUODENUM)

        7. THE LIVER IS COVERED BY VISCERAL PERITONEUM, EXCEPT AT THE "BARE" AREA AT THE AREA OF THE DIAPHRAM

        8. SEPTA OF CONNECTIVE TISSUES BRANCH INTO THE LIVER

        9. THE SEPTA DIVIDE THE LIVER INTO LOBULES WITH PORTAL TRIADS ( 3 VESSELS HEPATIC PORTAL, HEPATIC ARTERY, DUCT )

        10. CENTRAL VEIN IN EACH LOBULE - CENTRAL VEINS FORM THE HEPATIC VESSELS WHICH EXITS ON THE POSTERIOR, SUPERIOR SURFACE

        11. THIS EMPTIES INTO THE INFERIOR VENA CAVA

        12. LIVER FUNCTIONS:

          CARBOHYDRATE METABOLISM- GLUCOSE TO/FROM GLYCOGEN
          NON-CARBOHYDRATES TO GLUCOSE
          LIPID METABOLISM- LIPOPROTEINS, PHOSPHOLIPIDS,
          CHOLESTEROL SYNTHESIS
          CONVERT CARBOHYDRATES AND PROTEINS TO FATS
          PROTEIN METABOLISM- DEAMINATION - SYN. UREA
          DETOX- SECRETES BILE

        13. HEPATIC FUNCTION:

          BILIRUBIN METABOLISM- 250-350 FORMED DAILY
          SOURCES: HEMOGLOBIN OF DEGENERATING RED BLOOD CELLS,
          RED BLOOD CELLS PRECURSOR IN MARROW,
          HEME PROTEINS OF LIVER AND OTHER TISSUE

          BILIRUBIN: INSOLUABLE IN WATER, TRANSPORTED PLASMA
          BOUND TO ALBUMIN, CANNOT CROSS CELL MEMBRANE
          (EXCEPT IN LIVER), NOT FOUND IN URINE

          CONJUGATION- FREE BILIRUBIN CONCENTRATED IN LIVER,
          COMBINED WITH GLUCURONIC ACID TO FORM CONJUGATED BILIRUBIN

        14. HEPATIC EXCRETION: SECRETED INTO BILE (CANAIS)

          BILIRUBIN CONVERTED INTO: STERCOBILINOGENS IN GUT UROBILINOGEN IN URINE

          JAUNDICE- YELLOWISH SKIN, SCLERS CAUSES- VARIOUS UNCONJUGATED HYPERBILIRUBINEMIA : INCREASED FORMATION, DECREASED HEPATIC UPTAKE, DECREASED CONJUGATION >CONJUGATED HYPERBILIRUBINEMIA : HEPATIC DISEASE, BILIARY OBSTRUCTION

      9. GALL BLADDER- CAPACITY 20-60 MILLILITERS

        12 HOURS OF SECRETION (450 ML) CAN BE STORED BECAUSE WATER AND SALTS ARE REMOVED BY ACTIVE AND OSMOSIS. CONCENTRATED 12-20 FOLD

        1. SMALL SAC ON THE INFERIOR SURFACE OF THE LIVER
        2. THREE TUNICS MAKEUP THE GALL BLADDER

          1. INNER MUCOSA WITH FOLDS (RUGAE)
          2. MUSCULARIS LAYER OF SMOOTH MUSCLE
          3. OUTER COVERING OF CONNECTIVE TISSUE
        3. GALL BLADDER CONNECTED TO THE COMMON BILE DUCT BY CYSTIC DUCT.

        4. SPHINCTER OF ODDI- RELAXES AND ALLOWS BILE TO FLOW TO THE DUODENUM.

      10. PANCREAS

        1. CONTAINS BOTH ENDOCRINE AND EXOCRINE TISSUE

        2. CONSISTS OF A BODY, HEAD, AND TAIL

        3. ENDOCRINE PORTION IS CALLED THE ISLETS OF LANGERHANS

          A. PRODUCE INSULIN (BETA) AND GLUCAGON (ALPHA)
          B. THESE CONTROL LEVELS OF BLOOD GLUCOSE AND AMINO ACIDS.

        4. EXOCRINE PORTIONS ARE COMPOSED OF:

          1. ACINI (PRODUCE DIGESTIVE ENZYMES)
          2. ACINI FORM LOBULES SEPARATED BY SEPTA
          3. INTERLOBAR DUCTS ATTACH TO PANCREATIC DUCT
          4. THIS JOINS THE COMMON HEPATIC DUCT AT THE HEPATOPANCREATIC AMPULLS.

        5. FROM PANCREAS, ARE SECRETED INACTIVE TRYPSINOGEN- (enterokinase) -> TRYPSIN CHYMOTRYPSINOGEN- (trypsin) -> CHYMOTRYPSIN PROCARBOXYPEPTIDASE- (trypsin) -> CARBOXYPEPTIDASE

      11. LARGE INTESTINE (COLON)

        1. CECUM IS AT THE PROXIMAL END

        2. AT THE END IS THE VERMIFORM APPENDIX (MCBURNEYS POINT)

        3. THE COLON IS APPROXIMATELY 1.5 TO 1.8 M LONG

        4. IS DIVIDED INTO THE FOLLOWING SECTIONS:

          A. ASCENDING COLON (ILIOCECAL SPHINCTER)
          B. HEPATIC FLEXURE
          C. TRANSVERSE COLON
          D. SPLENIC FLEXURE
          E. DESCENDING COLON
          F. SIGMOID (NOT IN CAT)
          G. RECTUM
          H. ANAL CANAL (ANUS)

        5. CIRCULAR LAYER OF MUSCLE IS COMPLETE

        6. LONGITUDINAL LAYER FORMS THE TENIAE COLI

        7. CONTRACTIONS OF THE TENIAE COLI FORM THE HASTURA

        8. ANAL CANAL CONTAINS THE INTERNAL AND EXTERNAL ANAL SPHINCTER

      12. CHARACTERISTICS OF G.I. WALL

        1. FUNCTIONS AS A SYNCYTIUM

          1. BUNDLES OF 1000+ FIBERS
          2. FIBERS ELECTRICALLY CONNECTED BY GAP JUNTIONS
          3. IMPULSE TRAVELS RAPIDLY FROM FIBER TO FIBER
          4. CONTINUAL SLOW ELECTRICAL ACTIVITY
          5. ALLOWS FOR TWO BASIC TYPES OF WAVES

          1. SLOW WAVES:
            1. ARE NOT ACTION POTENTIALS
            2. SLOW UNDULATING CHANGES IN THE MEMBRANE POTENTIAL
            3. OCCURS 3 PER MINUTE IN STOMACH AND 12 PER MINUTE IN SMALL INTESTINE

          2. SPIKES:
            1. TRUE ACTION POTENTIALS
            2. OCCUR AUTOMATICALLY WHEN RESTING POTENTIAL
            3. GOES BELOW 40 MILLI VOLTS= 1-10 SPIKES PER SECOND

        2. NEURAL CONTROL- ENTERIC NERVOUS SYSTEM

          1. FROM ESOPHAGUS TO ANUS
          2. LOCATED IN WALL OF GUT
          3. NEURONS NUMBER 100 MILLION- SAME NUMBER AS FOUND IN THE SPINAL CORD
          4. TWO PLEXUS OF NERVES
            1. MYENTERIC PLEXUS
            2. SUBMUCOSAL PLEXUS
          5. CONTROLS GASTRO-INTESTINAL MOVEMENT AND SECRETION

        3. PARASYMPATHETIC- PRE GANGLIONIC

          1. CRANIO-SACRAL
          2. INCREASE ACTIVITY OF ENTERIC SYSTEM
          3. SOME MAY BE INHIBITED

        4. SYMPATHETIC- POST GANGLIONIC

          1. ORIGIN- T5-L2, INHIBITS ACTIVITY
          2. THORACO-LUMBAR
          3. SLIGHT EXTENT INHIBITS BY NOREPINEPHRINE ON SMOOTH MUSCLE AND GREATER EXTENT ON ENTERIC SYSTEM

        5. NEURO-TRANSMITTERS

          1. ACETYLCHOLINE- PARASYMPATHETIC
          2. NOREPINEPHRINE- SYMPATHETIC
          3. CHOLECYSTOKININ- AT GALL BLADDER

        6. G.I. MOVEMENT

          1. PERISTALSIS:

          2. MIXING MOVEMENTS:

            1. CAUSED BY SPHINCTER WHEN CHYME REACHES SPHINCTER
            2. LOCAL CONSTRICTIVE CONTRACTIONS

        7. SWALLOWING- THREE PHASES

          1. VOLUNTARY: PUSHED UPWARD AND BACK BY THE TONGUE

          2. PHARYNGEAL STAGE: BOLUS OF FOOD STIMULATES SWALLOWING REFLEX

            1. TRACHEA CLOSED
            2. ESOPHAGUS OPENED
            3. FAST PERISTALTIC WAVE FORCES FOOD TO UPPER ESOPHAGUS (1-2 SECONDS)

            * ALMOST NEVER INITIATED BY DIRECT STIMULI TO SWALLOWING REGIONS FROM HIGHER AREAS

            * SWALLOWING CENTER INHIBITS RESPIRATORY CENTER (BREATHING INTERRUPTED)

          3. ESOPHAGEAL STAGE: TWO TYPES PERISTALSIS

            1. PRIMARY: CONTINUATION OF PERISTALSIS THAT BEGINS IN THE PHARYNX ESOPHAGUS TO STOMACH (8-10 SECONDS)
            2. SECONDARY: IF PRIMARY FAILS TO MOVE FOOD TO STOMACH, SECONDARY BEGINS ENTERIC NERVOUS SYSTEM IN ESOPHAGUS -- VAGAL AFFERENT AND MEDULLA -- VAGAL EFFERENT -- STIMULATE PERISTALSIS

        8. STOMACH EMPTYING

          1. INTENSE ANTRAL PERISTALTIC CONTRACTIONS
            1. USUALLY ANTRAL PERISTALSIS WEAK
            2. BECOMES VERY STRONG
            3. SIX TIMES MORE POWERFUL THAN USUAL
            4. PRINCIPLE FACTOR THAT CONTROLS EMPTYING

          2. PYLORUS
            1. PYLORIC CIRCULAR MUSCLE IN SPHINCTER
            2. REAMAINS SLIGHTLY TONIC
            3. SMALL OPENING ALLOWS WATER AND SMALL PARTICLES TO PASS

        9. REGULATION

          1. GASTRIC FOOD VOLUME
            1. STRETCH REFLEX INITIATED

          2. GASTRIN
            1. RELEASED FROM ANTRAL MUCOSA
            2. INCREASES ACID SECRETIONS
            3. INCREASES ACTIVITY OF PYLORIC PUMP

          3. CCK AND SECRETION- SLOWS EMPTYING

            1. ENTROGASTRIC REFLEX- DUODENUM TO STOMACH
              DECREASE ANTRAL SLOWS STOMACH PROPULSIVE ACTION EMPTYING WHERE
              DUODENUM IS FULL
              CONTRACT PYLORIC SPHINCTER

          4. MOVEMENT IN SMALL INTESTINE

            1. TWO TYPES

            1. MIXING CONTRACTIONS
            2. PROPULSIVE CONTRACTIONS
              PERISTALTIC RUSH-- FAST PROPULSION TO CECUM EXAMPLE: DIARRHEA

        10. FUNCTION OF ILEOCECAL VALVE

          1. PREVENTS BACK FLOW
          2. GASTRIN RELAXES SPHINCTER
          3. ONLY 1500 ML OF CHYME ENTER CECUM PER DAY
          4. ILEOCECAL SPHINCTER CONTROLLED BY REFLEX FROM CECUM

            CECUM DISTENDS -- SPHINCTER CONTRACTS -- ILEAL PERISTALSIS DECREASED

            *APPENDICITIS MAY CAUSE STOPPAGE OF FOOD THROUGH VALVES.

        11. MOVEMENTS OF THE COLON

          *TYPES OF PERISTALSIS IN SMALL INTESTINE IS RARE IN COLON.

          1. MIXING MOVEMENTS- HAUSTRATION

            1. TAENIA COLI CONTRACT PRODUCING HAUSTRATION
            2. FECAL MATERIAL DUG INTO AND ROLLED OVER EXPOSING ALL MATERIAL TO SURFACE OF LARGE INTESTINE

          2. PROPULSIVE- "MASS" MOVEMENT

            1. EXTRINSIC NERVES CONTROL MOST MASS MOVEMENT
            2. GASTRO-COLIC AND DUODENO-COLIC REFLEXES AFTER A MEAL

          3. DEFECATION

            1. INTERNAL SPHINCTER (SMOOTH MUSCLE) - INVOLUNTARY
            2. EXTERNAL SPHINCTER (STRIATED) - VOLUNTARY
            3. RECTUM NORMALLY EMPTY WHEN FECES ENTERS
            4. ENTERIC NERVOUS SYSTEM CAUSES CONTRACTION OF SPHINCTERS -- RELAX -- DEFECATION

          PART II : FUNCTION AND PHYSIOLOGY OF DIGESTIVE SYSTEM



          ENZYME OR FLUID SOURCE FUNCTION
          (SALIVA) SALIVARY GLANDS
          SEROUS
          SALIVARY AMYLASE
          (PTYALIN)


          MUCUS

          SUB MANIBULAR
          PARTOIDBR



          SUBLINGUAL

          MOISTEN FOOD
          STARCH DIGESTION


          LUBRICATE FOOD

          (GASTRIC SECRETIONS)
          HCL

          PEPSINOGEN

          MUCUS

          PARIETAL CELLS

          CHIEF CELLS

          MUCOSAL CELLS

          ACTIVATE PEPSIN

          DIGEST PROTEIN

          PROTECTION

          (LIVER)
          BILE

          * BILE CONSISTS OF:

          LIVER

          SODIUM GLYCHOLATE (BILE SALT)
          SODIUM TAUROCHOLATE (BILE SALT)
          FROM CHOLESTEROL
          CHOLESTEROL
          BILIVERDIN
          BILIRUBIN
          MUCUS
          FAT
          LECITHIN
          CELLS AND CELLULAR DEBRIS

          EMULSIFY FATS
          LIPASES DIGEST

          (PANCREAS) STORED IN INACTIVE FORM IN ZYMOGEN GRANULES,
          SECRETED IN INACTIVE FORMS (PROTEIN ENZYME)



          TRYPSIN
          CHYMOTRYPSIN
          CARBOXYPEPTIDASE
          PANCREATIC AMYLASE
          PANCREATIC LIPASE
          RIBONUCLEASE
          DEOXYRIBONUCLEASE
          CHOLESTEROL ESTERASE




          BICARBONATE IONS

          PANCREAS
          PANCREAS
          PANCREAS
          PANCREAS
          PANCREAS
          PANCREAS
          PANCREAS
          PANCREAS




          PANCREAS

          DIGESTS PROTEIN
          DIGESTS PROTEIN
          DIGESTS PROTEIN
          DIGESTS CARBO.
          DIGESTS FAT
          DIGESTS RNA
          DIGESTS DNA
          FORMS CHOLESTEROL AND FREE FATTY ACID

          pH REGULATION

          (SMALL INTENTINE)
          ENZYME SECRETED FROM ACTION
          AMINOPEPTIDASE
          MUCUS


          PEPTIDASES


          AMYLASE
          ENTEROKINASE
          SUCRASE
          MALTESE
          ISOMALTASE
          LACTASE
          LIPASE

          EPITHELIUM
          DUODENAL GLANDS
          GOBLET CELLS
          EPITHELIUM


          EPITHELIUM
          EPITHELIUM
          EPITHELIUM
          EPITHELIUM
          EPITHELIUM
          EPITHELIUM
          EPITHELIUM

          SPILTS-POLYPEPTIDES PROTECTION HCL


          SPILTS AMINO ACIDS FROM POLYPEPTIDES

          DIGEST CARBO.
          ACTIVATES TRYPSIN
          SPLITS SUCROSE
          SPLITS MALTOSE
          SPILTS ISOMALTASE
          SPILTS LACTOSE
          SPILTS FATS

          GASTROINTESTINAL HORMONES

          HORMONE SITE OF
          PRODUCTION
          METHOD
          STIMULUS
          SECRETORY
          EFFECT
          MOBILITY
          EFFECT
          GASTRIN
          INCREASE
          MOTILITY)
          GASTRIN/ENTERIC
          (STOMACH/DOU)
          DISTENTION INCRESE
          GASTERIC
          SEC.
          INCREASE
          GASTRIC
          EMPT.
          SECRETIN
          (DECREASE MOTILITY,
          CAUSES RELEASE OF
          BICARBONATE, STIMULATES PANCREATIC JUICE AND BILE)
          DUODENUM ACIDITY INHIBITS
          GASTERIC
          SEC.
          INHIBITS
          MOTILITY
          C.C.K.
          1. SLOWS PYLORIC PUMP
          2. INCREASE SPHINCTER CONTRACTIONS
          3. COMPETITIVE INHIBITOR TO BLOCK
          ACTION OF GASTRIN
          CHOL- BILE, CYST- BLADDER, KININ- TO MOVE
          INTESTINE FATTY ACID STIMULATES
          PANCREATIC SEC.
          CONTRACT GALL BLADDER
          RELAX HEPATOPANCREATIC
          AMPULLAR SPHINCTER
          INHIBITS
          GASTRIC
          SEC.
          GASTRIC
          INHIBITORY
          PEPTIDE
          DUODENUM FATTY ACID INHIBITS PEPTIDE
          MOTILITY
          SLOWS RELEASE OF
          GASTRIC SECRETIONS
          VASOACTIVE
          INTESTINAL PEPTIDE
          (VIP)
          STIMULATES INCREASED
          ELECTROLYTE
          PRODUCTION, INCREASE
          WATER IN LAMEN BY
          OSMOSIS
          STIMULATES PANCREAS
          PANCREOZYMIN * SAME AS CCK ZYMIN- ENZYME PRODUCER STIMULATES PANCREAS

          SPHINCTER: CARDIAC (CLOSE), PYLORIC (OPEN), ILEOCECAL (OPEN)

          PART III : PHYSIOLOGY OF DIGESTION

          1. MASTICATION

            1. FOOD IS CHEWED
            2. MASTICATION REFLEX
              1. PRESENCE OF FOOD IN THE MOUTH STIMULATES SENSORY RECEPTORS
              2. REFLEX INTEGRATED IN THE MEDULLA OBLONGATA

              3. DEGLUTITION

                1. SWALLOWING OF FOOD BOLUS
                2. THREE PHASES:
                  1. VOLUNTARY STAGE
                  2. PHARYNGEAL PHASE- SWALLOWING RECEPTORS STIMULATED
                  3. ESOPHAGEAL PHASE

                  4. STOMACH

                    1. CEPHALIC PHASE
                      1. CEPHALIC STAGE IS THE SENSATIONS OF TASTE AND SMELL
                      2. THIS STIMULATES THE MEDULLA TOO INFLUENCE GASTRIC SECRETIONS
                      3. NERVE IMPULSE IS SENT VIA THE VAGUS NERVE TO THE STOMACH
                      4. THIS STIMULATES HCL, PEPSINOGEN, AND GASTRIN SECRETION

                      5. GASTRIC PHASE
                        1. DISTENSION OF THE STOMACH STIMULATES GASTRIN SECRETIONS
                        2. ACTIVATES CNS AND LOCAL REFLEXES THAT PROMOTE SECRETION
                        3. PERISTALTIC WAVES PUSH THE MIXTURE TOWARD THE DUODENUM
                        4. TYPE OF MEAL DETERMINES HOW LONG FOOD WILL REMAIN

                          DUODENAL PHASE

                          1. AS CHYME ENTERS THE DUODENUM, IT STIMULATES THE ENTEROGASTRIC REFLEX
                          2. AS A RESULT FEWER PARASYMPATHETIC IMPULSES REACH THE STOMACH
                          3. PERISTALSIS IN STOMACH DECREASED
                          4. IF CHYME HAS A HIGH FAT CONTENT, CHOLESTOKININ WILL BE RELEASED FROM THE INTESTINAL WALL

                          5. SMALL INTESTINE PHYSIOLOGY
                            1. LINED WITH VILLI
                            2. MOST NUMEROUS IN DUODENUM AND PROXIMAL PORTION OF JEJUNUM
                            3. EACH VILLUS CONTAINS:
                              1. LAYER OF SIMPLE COLUMNAR EPITHELIUM
                              2. A CORE CONTAINING BLOOD VESSELS
                              3. LACTEAL WITH A LYMPH CAPILLARY
                              4. NERVE

                              5. ABSORPTION OF THE SMALL INTESTINE

                                1. CARBOHYDRATE DIGESTION BEGINS IN THE MOUTH AND COMPLETED IN THE SAMLL INTESTINE. GLUCOSE ABSORBED INTO BLOOD
                                2. PROTEIN DIGESTION BEGINS IN THE STOMACH AND COMPLETED IN THE SMALL INTESTINE. AMINO ACIDS ABSORBED INTO BLOOD
                                3. FAT DIGESTION:
                                  1. FATTY ACID MOLECULES ARE DISSOLVED AND DIFFUSE INTO THE VILLUS EPITHELIUM
                                  2. THESE CELLS REMANUFACTURE FAT CELLS
                                  3. ENCASED IN PROTEIN AND BECIME LIPOPROTEINS (CHYLOMICRONS)
                                  4. LYMPH CARRIES THE CHYLOMICRONS TO BLOOD VESSEL
                                  5. TRANSPORTED TO CAPILLARIES IN MUSCLE AND FAT TISSUE
                                  6. THE ENZYME LIPOPROTEIN, LIPASE RELEASES FATTY ACIDS AND MONOGLYCERIDES FROM THE CHYLOMICRONS
                                  7. THEY ENTER ADIPOSE TISSUE OR MUSCLE FOR STORAGE
                                  8. REMAINDER OF THE CHYLOMICRON TRAVELS TO THE LIVER WHERE IT IS DESTROYED


                                    ***NOTE: SOME SHORT CHAIN FATTY ACIDS ARE DIRECTLY ABSORBED INTO THE BLOOD SYSTEM