DIGESTIVE SYSTEM

FUNCTION• TO CHANGE COMPLEX

ORGANIC NUTRIENT MOLECULES INTO SIMPLE ORGANIC AND INORGANIC MOLECULES

DIVISIONS• ALIMENTARY TUBE – MOUTH TO ANUS• ACCESSORY ORGANS – OUTSIDE OF

THE ALIMENTARY TUBE - TEETH, TONGUE, SALIVARY GLANDS,

GALL BLADDER, PANCREAS, LIVER -CONTRIBUTES TO THE DIGESTIVE

PROCESS BUT IT DOESN’T HAPPEN WITHIN THESE ORGANS

TYPES OF DIGESTION

• MECHANICAL – PHYSICAL BREAKDOWN OF FOOD INTO SMALLER PIECES

• CHEMICAL – DIGESTIVE ENZYMES

END PRODUCTS• CARBOHYDRATES –

MONOSACCHARIDES EX. GLUCOSE, FRUCTOSE,

GALACTOSE• PROTEINS – AMINO ACIDS• FATS – FATTY ACIDS AND GLYCEROL• RELEASE OF VITAMINS, MINERALS,

AND WATER

ORAL CAVITY• AKA BUCCAL CAVITY• TEETH ARE FOR MECHANICAL

DIGESTION• 2 SETS - DECIDUOUS – 6 MO. TO 2 YR.

(20 TEETH) - PERMANENT – START ABOUT 6

YEARS OLD (32 TEETH)

LAYERS OF THE TOOTH• ENAMEL – OUTERMOST LAYER

THAT IS RESISTANT TO DECAY, HARD SURFACE

• DENTIN – SIMILAR TO BONE, FORMS THE ROOT OF THE TOOTH

• PULP CAVITY – INNERMOST LAYER THAT CONTAINS BLOOD VESSELS AND NERVE ENDINGS

TONGUE• TASTE BUDS AKA PAPILLAE ARE

ON THE TOP• TASTE IS CN VII AND CN IX• TONGUE MANIPULATES FOOD• SWALLOWING IS INITIALLY AN

VOLUNTARY ACTION BUT ONCE IT IS A BOLUS AND PAST THE UVULA, IT IS INVOLUNTARY

• CN XII MOVES THE TONGUE

SALIVARY GLANDS• PAROTID GLANDS• SUBMANDIBULAR GLANDS• SUBLINGUAL GLANDS

• SALIVARY AMYLASE INITIATES CARBOHYDRATE BREAKDOWN IN THE MOUTH

PHARYNX• NASOPHARYNX• OROPHARYNX• LARYNGOPHARYNX• FUNCTION IS SWALLOWING

WHERE THE REFLEX IS INITIATED BY THE MEDULLA

ESOPHAGUS• TAKES FOOD FROM THE

PHARYNX TO THE STOMACH• PERISTALSIS FOR MOVEMENT OF

THE FOOD• LES• GERD• NO ENZYMES• MUCOUS COATED

STRUCTURAL LAYERS OF SYSTEM

• 4 LAYERS• MUCOSA – INNER LAYER• SUBMUCOSA – CONTAINS

MEISSNER’S PLEXUS THAT REGULATES SECRETIONS

• EXTERNAL MUSCULAR LAYER – CONTAINS AUERBACH’S PLEXUS THAT ALLOWS CONTRACTIONS AND PERISTALSIS

• SEROSA – OUTERMOST LAYER

• HOW LONG ARE YOUR INTESTINES? At least 25 feet in an adult. Be glad you're not a full-grown horse -- their coiled-up intestines are 89 feet long!

• Chewing food takes from 5-30 seconds • Swallowing takes about 10 seconds • Food sloshing in the stomach can last 3-4 hours • It takes 3 hours for food to move through the

intestine • Food drying up and hanging out in the large

intestine can last 18 hours to 2 days! • Americans eat about 700 million pounds of peanut

butter. • Americans eat over 2 billion pounds of chocolate a

year. • In your lifetime, your digestive system may handle

about 50 tons!!

STOMACH• LOCATED IN THE LUQ IN FRONT OF SPLEEN• BOTH MECHANICAL AND CHEMICAL

DIGESTION TAKES PLACE• MOST COMMON AREA FOR ULCER• SECRETES HCl THAT INITIATES PROTEIN

BREAKDOWN AND KILLS BACTERIA• CHIEF CELLS SECRETE PEPSIN• MUCOUS CELLS SECRETE MUCOUS• CREATES CHYME• CHYME LEAVES STOMACH THROUGH

PYLORIC SPHINCTER• pH

GASTRIC ULCERS

SMALL INTESTINE• BETWEEN THE STOMACH AND THE

CECUM• ALKALINE• ABOUT 20 FEET LONG3 PARTS• DUODENUM – 10 INCHES LONG.

SECOND MOST COMMON AREA OF ULCERS - pH

• JEJUNUM – ABOUT 8 FT. LONG• ILEUM – ABOUT 11 FT. LONG• DIGESTION AND ASSIMILATION

OCCURS HERE

ABSORPTION OF NUTRIENTS

• PLICA CIRCULARIS – CIRCULAR FOLDS

• VILLI• MICROVILLI• THESE INCREASE SURFACE AREA• DIFFUSION, ACTIVE TRANSPORT,

OSMOSIS

INCREASES SURFACE AREA

LARGE INTESTINE• ABOUT 5 FT. LONG BUT 2.5 INCHES IN

DIAMETER• PARTS INCLUDE: -CECUM -ASCENDING COLON -TRANSVERSE COLON -DESCENDING COLON -SIGMOID COLON - RECTUM -ANUS

• ILEOCECAL VALVE – BETWEEN ILEUM AND CECUM AND PREVENTS THE BACKFLOW OF FECAL MATERIAL

• APPENDIX IS ATTACHED TO THE CECUM

• NO DIGESTION OCCURS HERE• MUCOUS FOR LUBRICATION• HAUSTRA INCREASES SURFACE AREA• ABSORPTION OF WATER, MINERALS,

AND VITAMINS• VITAMINS PRODUCED BY NORMAL

FLORA

ELIMINATION• ACCOMPLISHED BY THE

DEFECATION REFLEX WHICH MAY BE CONTROLLED VOLUNTARILY

• INTERNAL SPHINCTER (INVOLUNTARY)

• EXTERNAL SPHINCTER (VOLUNTARY)

ENZYMES• FUNCTION WITHIN THE SMALL

INTESTINE• COME FROM THE LIVER,

PANCREAS, SMALL INTESTINE

LIVER• FORMS BILE • BILE EMULSIFIES (MECHANICAL

DIGESTION)• BILE IS MADE BY THE LIVER

GALL BLADDER• STORES BILE• CCK STIMULATES THE

CONTRACTION OF THE GALL BLADDER TO RELEASE BILE AND SEND IT TO THE DUODENUM

PANCREAS• RELEASES ENZYMES TO BREAK

DOWN ALL MACRONUTRIENTS• AMYLASE – FOR CARBOHYDRATE

BREAKDOWN• LIPASE – FOR FAT BREAKDOWN• TRYPSIN – FOR PROTEIN

BREAKDOWN