1. The Digestive System

2. DIGESTION
– the process of changing complex solid foods into simpler soluble forms which can be absorbed by body cells.
ENZYMES – chemical substances that promote chemical reactions in living things.

3. ALIMENTARY CANAL digestive tract or gastrointestinal tract (GI Tract).
A 30 ft. tube from mouth to anus.
Accessory organs of digestion:
Tongue
Teeth
Salivary glands
Pancreas
Liver
Gall bladder

5. PERITONEUM Lining of the Digestive System
– double-layered serous membrane that lines the abdominal cavity

6. Functions of the Digestive System
Physical breakdown of food
Chemical digestion of food into the end products of fat, carbohydrates and protein.
Absorb nutrients into blood capillaries of the small intestines
Eliminate waste products of digestion

7. Structure of Organs of Digestion
MOUTH
Food enters digestive system through mouth
Inside of mouth covered with mucous membrane
Roof of mouth is HARD PALATE (bone) and soft palate

8. UVULA flap that hangs off the soft palate
prevents food from going up the nose when you swallow

10. TONGUE Attached to floor of mouth Helps in chewing and swallowing
Made of skeletal muscle attached to four bones
Taste buds on the surface

11. SALIVARY GLANDS Three pairs of glands
PAROTID – largest salivary glands, they become inflamed during mumps
Secrete saliva
Acids, secreted by bacteria in the mouth to break down sugar, cause tooth decay
An adult secretes about 2 pints of saliva a day

13. TEETH GINGIVA – gums, support and protect teeth
MASTICATION – chewing, teeth help in mechanical digestion
DECIDUOUS teeth – baby teeth (#20)
Adult mouth has 32 teeth
Some people never develop
the back four molars (wisdom teeth)

14. Some people never develop
the back four molars (wisdom teeth)
A baby’s first teeth start to appear when it is about 6 months old
By the age of 5, most children have 20 milk teeth, which later fall out to make room for adult teeth
Adults usually have 16 teeth in each of the upper and lower jaws
At the front of the mouth, in the upper & lower jaw, there are four incisors for cutting food

15. At each side of the incisors, there is a canine tooth (4 in all) which are for piercing the food
Behind each canine there are two premolars & 3 molars, which are designed for grinding food.
The enamel that covers teeth is the hardest substance in the body
Molars have up to 4 roots, which anchor them securely in the jawbone. The nerves & blood vessels pass out through tiny holes in the base of each root
The crown is broad & flat for crushing.

16. ESOPHAGUS ESOPHAGUS Muscular tube, 10” long Connects pharynx
and stomach

17. STOMACH Upper part of abdominal cavity
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 in folds when the stomach is empty
Stomach has muscular coat that allows it to contract (peristalsis) and push food into the small intestine

18. -The stomach can stretch to hold 4 pints of fluid -gastric glands produce about 6 pints of acidic fluid each day - Food spends 2-4 hrs. in the stomach

19. SMALL INTESTINE
DUODENUM – first segment, curves around pancreas, 12” long
JEJUNUM – next section, 8 ft. long
ILEUM – final portion, feet long
ABSORPTION – in small intestine, digested food passes into bloodstream and on to body cells, indigestible passes on to large intestine

20. The small intestine is about 112 in. long
The small intestine doubles in length when a person dies

22. Accessory Organs of Digestion
PANCREAS
Located behind stomach
Exocrine function –
secretes digestive enzymes
Also has endocrine function

23. LIVER Largest organ in the body
Located below the diaphragm, upper right quadrant
Connected to
gallbladder
and small
intestine by ducts

24. Functions: Produce and store glucose in the form of GLYCOGEN
Detoxify alcohol, drugs and other harmful substances
Manufacture blood proteins
Manufactures bile
Store Vitamins A, D and B complex

25. GALL BLADDER Stores and concentrates bile until needed by the body
Small green organ,
inferior surface of the liver
When fatty foods
digested, bile
released by gallbladder

26. LARGE INTESTINE CHYME – semi-liquid food Approx 2” in diameter
Also called the colon
CECUM – lower right portion of large intestine
Food usually spends at least 10 hrs. in the large intestine. It can be there for up to several days.

27. APPENDIX is finger-like projection off cecum
RECTUM – last portion of large intestine
ANUS – external opening

28. DIGESTION
BOLUS – soft, pliable ball – creating from chewing and addition of saliva – it slides down esophagus
PERISTALSIS – wavelike motions, moves food along esophagus, stomach and intestines

29. In the mouth… saliva softens food to make it easier to swallow
PTYALIN in saliva converts starches into simple sugar
under nervous control – just thinking of food can cause your mouth to water

30. In the stomach… gastric (digestive) juices are released
stomach walls churn and mix (This mixture is chyme)
small amount of chyme enters duodenum at a time - controlled by pyloric sphincter
takes 2-4 hours for stomach to empty

31. In the small intestine…
where digestion is completed and absorption occurs
addition of enzymes from pancreas and bile from liver/gallbladder

32. 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 and Vitamin K
gas formation – 1-3 pints/day, pass it through rectum (FLATULENCE) 14 times a day,
bacteria produces the gas

33. FECES
undigested semi-solid consisting of bacteria, waste products, mucous and cellulose
About 75%of feces
is made up of water.
The rest is mainly
undigested plant fibers
and germs
Feces reach the rectum between
hrs. after swallowing

34. DEFECATION
when large intestine fills, defecation reflex triggered – colon and rectal muscles contract while internal sphincter relaxes – external anal sphincter under conscious control

35. Some people may have a bowel movement several times a day; some only twice a week. Both levels of activity are normal.

36. Digestive Disorders

37. HEARTBURN Acid reflux Symp – burning sensation
Rx – avoid chocolate and peppermint, coffee, citris, fried or fatty foods, tomato products – stop smoking – take antacids – don’t lay down 2-3 hours after eating

38. GASTROENTERITIS
Inflammation of mucous membrane lining of stomach and intestine
Common cause = virus
Symps – diarrhea and vomiting for hours
Complication = dehydration

39. ULCER Sore or lesion that forms in the mucosal lining of the stomach
Gastric ulcers in the stomach and duodenal ulcers in the duodenum
Cause – H. pylori (bacteria) is primary cause
Lifestyle factors that contribute: cigarette smoking, alcohol, stress, certain drugs
Symp – burning pain in abdomen, between meals and early morning, may be relieved by eating or taking antacid
Diagnosis – x-ray, presence of bacteria
Rx – H2 blockers (drugs) that block release of histamine
ULCER

41. APPENDICITIS When appendix becomes inflamed
If it ruptures, bacteria from appendix can spread to peritoneal cavity

42. HEPATITIS A Infectious hepatitis Cause – virus
Spread through contaminated food or H2O
Goes away on its own in most cases
Does not lead to long term liver problems

43. How is hepatitis A spread?
The disease is caused by the hepatitis A virus. The virus is found in the stool of an infected person. It is spread when a person eats food or drinks water that has come in contact with infected stool.
Sometimes a group of people who eat at the same restaurant can get hepatitis A. This can happen when an employee with hepatitis A doesn't wash his or her hands well after using the bathroom and then prepares food.
The disease can also spread in day care centers. Workers can spread the virus if they don't wash their hands well after changing a diaper.
Some things can raise your risk of getting hepatitis A, such as eating raw oysters or undercooked clams. If you're traveling in a country where hepatitis A is common, you can lower your chances of getting the disease by avoiding uncooked foods and tap water.

44. Can hepatitis A be prevented?
You can protect yourself from hepatitis A by getting a vaccine (Havrix or Vaqta). You will get it in a series of two shots. It is usually 100% effective if you get both shots before you are exposed to the virus.
The U.S. Centers for Disease Control and Prevention advises that all children get the hepatitis A vaccine when they are at least 1 year old.
If you have been around someone who you know has hepatitis A, the hepatitis A vaccine or an injection of immune globulin (IG) may prevent you from getting the disease. It’s important for you to get the shot within 2 weeks of being exposed to the virus.

45. How is it treated?
Hepatitis A goes away on its own in most cases. You can help yourself get better faster by drinking lots of water and eating a healthy mix of foods.
Unlike other forms of hepatitis, the hepatitis A virus does not lead to long-term illness or serious liver damage. Most people get well within a few months.
While you have hepatitis A, cut back on daily activities until all of your energy returns. As you start to feel better, take your time in getting back to your regular activities. If you try to meet your regular pace too soon, you may get sick again.
You can only get the hepatitis A virus once. After that, your body builds up a defense against it.

46. HEPATITIS B (Serum Hepatitis)
Caused by virus found in blood
Transmitted by blood transfusion or being stuck with contaminated needles (drug addicts)
Health care workers at risk and should be vaccinated
Use standard precautions for prevention
Virus can live outside the body on a dry surface for up to 10 days
Once infected, may take 1to 6 months for the infection and symptoms to develop

48. CIRRHOSIS Chronic, progressive disease of liver
Normal tissue replaced by fibrous connective tissue
75% caused by
excessive alcohol
consumption

49. CHOLECYSTITIS Inflammation of gallbladder CHOLELITHIASIS Gallstones
Can block the bile duct causing pain and digestive disorders
Small ones may pass on their own, large ones surgically removed
Surgical removal of gallbladder = CHOLECYSTECTOMY

51. 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

52. CONSTIPATION When defecation delayed, feces become dry and hard
Rx – diet with cereals, fruits, vegetables, (roughage), drinking plenty of fluids, exercise, and avoiding tension

53. JAUNDICE
Yellow color of the skin