1. Digestive System

2. Digestive System Digestion
Process of changing complex solid foods into simpler soluble forms which can be absorbed by body cells.
Enzymes
Chemical substances that promotes chemical reactions in living things
Alimentary Canal
Digestive tract/gastrointestinal tract.
30 ft tube from mouth to anus

3. Digestive System Peritoneum Functions
Double-layered serous membrane that lines the abdominal cavity
Functions
Physical breakdown of food
Chemical digestion of food into the end products of fat, carbohydrates, & protein
Absorb nutrients into blood capillaries of the small intestines
Eliminate waste products of digestion

4. Structure of Organs Mouth Food enters digestive system through mouth
Inside of mouth covered with mucous membrane
Roof of mouth is Hard Palate (bone) & soft palate
Uvula
Flap that hangs off soft palate
Prevents food from going up the nose when you swallow

5. Structure of Organs Tongue Salivary Glands Teeth
Attached to floor of mouth
Helps in chewing & swallowing
Made of skeletal muscle attached to 4 bones
Taste buds on the surface
Salivary Glands
Three pairs of glands
Secrete saliva
Teeth
Gingiva – gums, support & protect teeth
Mastication – chewing, mechanical digestion

6. Structure of Organs Esophagus Muscular tube, 10” long
Connects pharynx & stomach
Stomach
Cardiac sphincter – circular layer of muscle, controls passage of food into stomach
Pyloric sphincter – valve, regulates the entrance of food into duodenum
Rugae – mucous coat lining of stomach
Allows to contract (peristalsis) & push food into small intestine

8. Structure of Organs Small Intestine
Duodenum – 1st segment, curves around pancreas, 12” long
Jejunum – next section, 8 ft long
Ileum – final portion, ft long
Absorption – digested food passes into bloodstream & on to body cells
Undigestible passes on to large intestine

9. Structure of Organs Large Intestine (aka colon)
Chyme – semi-liquid food
~ 2” in diameter
Cecum – lower right portion
Appendix – finger-like projection off cecum
Rectum – last portion
Anus – external opening

10. Accessory Organs Pancreas Located behind stomach
Exocrine function – secretes digestive enzymes
Also has endocrine function
Gall Bladder
Small green organ, inferior surface of the liver
Stores & concentrates bile
Released when fatty foods are digested

11. Accessory Organs Liver Functions: Largest organ in he body
Located below the diaphragm (ULQ)
Connected to gallbladder & small intestine by ducts
Functions:
Produce & store glucose in the form of Glycogen
Detoxify alcohol, drugs & other harmful substances
Manufacture blood proteins
Manufactures bile
Store Vitamins A, D & B complex

12. Digestion Bolus soft, pliable ball
created from chewing & addition of saliva
it slides down esophagus
Peristalsis
wavelike motions, moves food along esophagus, stomach & intestines

13. Digestion In the mouth…
Saliva softens food to make it easier to swallow
PTYALIN in saliva converts starches into simple sugar
In the stomach…
Gastric (digestive) juices are released
Stomach walls churn & mix (mixture is chyme)
Small amount of chyme enters duodenum at a time – controlled by pyloric sphincter
Takes 2-4 hours for stomach to empty

15. Digestion In the small intestine…
Where digestion is completed & absorption occurs
Addition of enzymes from pancreas & bile from liver/gallbladder

17. Digestion In the large intestine…
Regulation of H2O balance by absorbing large quantities back into bloodstream
Bacterial action on undigested food
Decomposed products excreted through colon
Bacteria form moderate amounts of B complex & Vitamin K
Bacteria produce gas (1-3 pints/day…14 times a day)
Feces – undigested semi-solid consisting of bacteria, waste products, mucous & cellulose
Defecation – when lg. intestine fills, defecation reflex triggered.

18. Location of Parts and Function
oral cavity (mouth)
physical digestion
pharynx
common passage for digestion and respiration systems
tongue
tasting
positions food for ‘tooth work’
teeth
physical digestion of food
salivary glands
lubricate bolus, begin starch chemical digestion (salivary amylase)
epiglottis
direct food ball into esophagus and not into trachea (the “wrong way”)
esophagus
tube through which food passes into stomach
stomach
physical digestion (churns) and chemical digestion (protein)

19. cardiac sphincter
muscular ring acts as valve to contain food in stomach (top)
duodenum
(top)1st 15 cm of sm. intestine
bile duct, pancreatic duct enter here
pyloric sphincter
muscular ring; acts as valve to contain food in stomach
small intestine
chemical digestion of all foods, absorption of monomers
liver
produces bile and maintains blood glucose
gall bladder
stores bile (emulsifies fats)
pancreas
neutralizes pH (NaHCO3), secretes several enzymes
large intestine
absorption of H2O
cultures E. coli
appendix
? protection from pathogens
? vestigial structure
rectum
last 20 cm of large intestine
anus
undigested material passes out here

20. Digestive Disorders Heartburn Acid reflux Symptom – burning sensation
Rx – avoid chocolate & peppermint, coffee, citrus, fried or fatty foods, tomato products – stop smoking – take antacids – don’t lay down 2-3 hours after eating
Gastritis
Acute or chronic inflammation of the stomach lining
Gastroenteritis
Inflammation of mucous membrane lining of stomach & intestine lining. Usually caused by a virus.
Symps – diarrhea & vomiting for hours
Complication - dehydration

21. Digestive Disorders Ulcer
Sore or lesion that forms in the mucosal lining of the stomach. Bacteria is the primary cause.
Symptom – burning pain in the abdomen, between meals & early morning, may be relieved by eating or taking antacid
Colitis (Irritable Bowel Syndrome…IBS)
Large intestine inflamed
Symptom – episodes of constipation or diarrhea

23. Digestive Disorders Cirrhosis Chronic, progressive disease of liver
Normal tissue replaced by fibrous connective tissue
75% caused by excessive alcohol consumption
Cholelithiasis (gallstones)
May block bile duct causing pain

24. Digestive Disorders Diverticulosis
Little sacs (diverticuli) develop in wall of colon
Most people over age 60 have this
When sacs become inflamed = diverticulitis

25. Digestive Disorders Diarrhea
Loose, watery, frequent bowel movements when feces pass along colon too rapidly
Caused by infection, poor diet, nervousness, toxic substances or irritants in food
Constipation
When defecation delayed, feces become dry & hard
Rx – diet with cereals, fruits, vegetables (roughage) & drinking plenty of fluids

26. Digestive Disorders Gingivitis Inflammation of the gums Jaundice
Yellow color when bile pigment gets in bloodstream
Caries
Tooth decay (cavities)