The document describes the anatomy and functions of the digestive system. It lists and describes the major organs of the digestive system including the mouth, esophagus, stomach, small intestine, large intestine, liver, gallbladder and pancreas. It explains the processes of digestion, including mechanical and chemical breakdown of food as well as absorption of nutrients and elimination of waste. It also provides an overview of some common disorders that can affect the digestive system.

1. Anatomy & Physiology OF
HARISHANKAR SAHU
B.PHARMA FINAL YEAR
SRIP,KUMHARI
BY-
Digestive System

2. Organs of the Digestive System
 Mouth
 teeth
 Salivary glands
 Pharynx
 Esophagus
 Stomach
 Liver
 Gallbladder (GB)
 Pancreas
 Small intestine
 Large intestine
 Rectum
 Anus

3. Main Functions
Digesting food
– Physical and chemical breakdown of large food into
molecules: glucose, triglycerides, amino acids
Absorbing nutrients
– From intestines
– Circulated through the body by cardiovascular system
Eliminating waste
– Any food that cannot be digested or absorbed is expelled

4. Oral Cavity (mouth)
• Roof is palate
– Hard – bony anterior
– Soft – flexible
posterior
• Hanging down from
soft palate is uvula
– Speech production
– Location of gag reflex

5. Oral Cavity
• Cheeks are lateral
walls
• Lips are anterior
opening
• Entire cavity lined
with mucous
membrane

6. Oral Cavity
• Digestion begins when food enters mouth
– Mechanically broken up by chewing
• Tongue moves food within mouth
• Mixes with saliva
– Digestive enzymes
– Lubricates
• Taste buds on tongue surface
– Detect bitter, sweet, salty, sour flavors

7. Processes of the Mouth
 Mastication (chewing) of food
 Mixing masticated food with saliva
 Initiation of swallowing by the tongue
 Allowing for the sense of taste

8. Salivary Glands
• Produce saliva
– Prevents bacterial
infection
– Lubrication
– Contains salivary
amylase
• Breaks down starch

9. Three pairs of Salivary Glands
• Parotid – lateral side of face, anterior to ear, drain by parotid duct
to vestibule near 2nd upper molar
• Submandibular – medial surface of mandible – drain near lingual
frenulum drain posterior to lower molars
• Sublingual – in floor of mouth - drain near frenulum

10. Function
 Mixture of mucus and serous fluids
 Helps to form a food bolus
 Contains salivary amylase to begin
starch digestion
 Dissolves chemicals so they can be
tasted

11. Teeth
 The role is to masticate (chew) food
 Humans have two sets of teeth
1. Deciduous (baby or milk) teeth
 20 teeth are fully formed by age two
2. Permanent teeth
 Replace deciduous teeth beginning between the ages
of 6 to 12
 A full set is 32 teeth, but some people do not have
wisdom teeth

12. Classification of Teeth

13. Pharynx Anatomy
 Nasopharynx – not part of
the digestive system
 Oropharynx – posterior to
oral cavity
 Laryngopharynx – below
the oropharynx and
connected to the
esophagus

14. Pharynx Function
 Serves as a passageway for air and food
 Food is propelled to the esophagus by two
muscle layers
 Longitudinal inner layer
 Circular outer layer
 Food movement is by alternating contractions of
the muscle layers (peristalsis)

15. Esophagus
 10 inches long in adults
 Food enters from pharynx
 Runs from pharynx to stomach
through the diaphragm
 Conducts food by peristalsis
(slow rhythmic squeezing)
 Passageway for food only
(respiratory system branches off
after the pharynx)
Joins stomach at cardiac orifice*
Cardiac sphincter at cardiac orifice to
prevent regurgitation (food coming back up
into esophagus)

16. Stomach
• Lies mostly in LUQ
– But pain can be epigastric or
lower
• Just inferior to (below)
diaphragm
• Anterior (in front of) spleen
and pancreas
• Tucked under left lower margin
of liver
• Anchored at both ends but
mobile in between
• Capacity: 1.5 L food; max
capacity 4L (1 gallon)
16
epigastrium
junction
with
esophagus
funnel shaped
contains
pyloric
sphincter
dome

17. 17

18. Stomach
• J-shaped; widest part of alimentary canal
• Temporary storage and mixing – 4 hours
– Into “chyme”
• Starts food breakdown
– Pepsin (protein-digesting enzyme needing acid
environment)
– HCl (hydrochloric acid) helps kill bacteria
– Stomach tolerates high acid content but esophagus doesn’t
– why it hurts so much when stomach contents refluxes
into esophagus (heartburn; GERD)
• Most nutrients wait until get to small intestine to be
absorbed; exceptions are:
– Water, electrolytes, some drugs like aspirin and alcohol
(absorbed through stomach)
18

19. Stomach Functions
 Acts as a storage tank for food
 Site of food breakdown
 Chemical breakdown of protein begins
 Delivers chyme (processed food) to the
small intestine
 It secretes intrinsic factor which is
necessary for the absorption of vit.B12

20. Small intestine
• Longest part of alimentary canal (2.7-
5 m)
• Site of greatest amount of digestion
and absorption
• Small intestine has 3
subdivisions
– Duodenum – 5% of length
– Jejunum – almost 40%
– Ileum – almost 60%
• Modifications
– Circular folds or plicae circulares,
villi, lacteal, microvilli
• Cells of mucosa
– Absorptive, goblet,granular,
endocrine

21. • Small intestine designed for absorption
– Huge surface area because of great length
– Structural modifications also increase absorptive area
• Circular folds (plicae circulares)
• Villi (fingerlike projections) 1 mm high – simple columnar epithelium: velvety
• Microvilli
*
Absorptivie
cell with
microvilli to
increase
surface area
& many
mitochondria:
nutrient
uptake is
energy-
demanding

22. Villi of the Small Intestine
 Fingerlike
structures formed
by the mucosa
 Give the small
intestine more
surface area

23. Microvilli of the Small Intestine
 Small projections
of the plasma
membrane
 Found on
absorptive cells
Figure 14.7c

24. Structures Involved in Absorption of Nutrients
 Absorptive cells
 Blood
capillaries
 Lacteals
(specialized
lymphatic
capillaries)

25. Digestion in the Small Intestine
Pancreatic enzymes play the major digestive
function
 Help complete digestion of starch (pancreatic
amylase)
 Carry out about half of all protein digestion
(trypsin, etc.)
 Responsible for fat digestion (lipase)
 Digest nucleic acids (nucleases)
 Alkaline content neutralizes acidic chyme

26. Absorption in the Small Intestine
 Water is absorbed along the length of the small
intestine
 End products of digestion
 Most substances are absorbed by active
transport through cell membranes
 Lipids are absorbed by diffusion
 Substances are transported to the liver by the
hepatic portal vein or lymph

27. Large Intestine
 Larger in diameter,
but shorter than the
small intestine
 Frames the internal
abdomen
 Digested residue
reaches it Main
function: to absorb
water and
electrolytes

28. Structures of the Large Intestine
 Cecum – saclike first part of the large intestine
 Appendix
 Accumulation of lymphatic tissue that sometimes becomes
inflamed (appendicitis)
 Hangs from the cecum
 Colon
 Ascending
 Transverse
 Descending
 S-shaped sigmoidal
Rectum = Rectum is area for storage of feces
Leads to the anus, the external opening of the alimentary canal
Defecation

29. Functions of the Large Intestine
 Absorption of water
 Eliminates indigestible food from the
body as feces
 Does not participate in digestion of food
 Goblet cells produce mucus to act as a
lubricant

30. Food Breakdown and Absorption in
the Large Intestine
 No digestive enzymes are produced
 Resident bacteria digest remaining
nutrients
Produce some vitamin K and B
Release gases
 Water and vitamins K and B are absorbed
 Remaining materials are eliminated via
feces

31. Accessory Organs of the Digestive
System
Gallbladder
Liver
Pancreas

32. The Liver
• Largest gland in the body
(about 3 pounds)
• Over 500 functions
• Inferior to diaphragm in
RUQ and epigastric area
protected by ribs
• R and L lobes
– Plus 2 smaller lobes
• Falciform ligament
– Mesentery binding liver to
anterior abdominal wall
• 2 surfaces
– Diaphragmatic
– Visceral
• Covered by peritoneum
– Except “bare area” fused to
diaphragm
32

33. 33

34. Functions of the Liver
• Bile production
– Salts emulsify fats, contain pigments as bilirubin
• Storage
– Glycogen, fat, vitamins, copper and iron
• Nutrient interconversion
• Detoxification
– Hepatocytes remove ammonia and convert to urea
• Phagocytosis
– Kupffer cells phagocytize worn-out and dying red and white blood cells,
some bacteria
• Synthesis
– Albumins, fibrinogen, globulins, heparin, clotting factors

35. Role of the Liver in Metabolism
 Several roles in digestion
 Detoxifies drugs and alcohol
 Degrades hormones
 Produce cholesterol, blood proteins
(albumin and clotting proteins)
 Plays a central role in metabolism

36. Gallbladder
• Bile is produced in the liver
• Bile is stored in the gallbladder
• Bile is excreted into the duodenum when needed (fatty meal)
• Bile helps dissolve fat and cholesterol
• If bile salts crystallize, gall stones are formed
– Intermittent pain: ball valve effect causing intermittent obstruction
– Or infection and a lot of pain, fever, vomiting, etc.
36
*

37. Figure:- The Gallbladder

38. Pancreas
 Produces a wide spectrum
of digestive enzymes that
break down all categories
of food
 Enzymes are secreted into
the duodenum
 Alkaline fluid introduced
with enzymes neutralizes
acidic chyme
 Endocrine products of
pancreas
 Insulin
 Glucagons

39. Pancreas
• Anatomy
– Endocrine
• Pancreatic islets produce
insulin and glucagon
– Exocrine
• Acini produce digestive
enzymes
– Regions: Head, body, tail
• Secretions
– Pancreatic juice
(exocrine)
• Trypsin
• Chymotrypsin
• Carboxypeptidase
• Pancreatic amylase
• Pancreatic lipases
• Enzymes that reduce DNA
and ribonucleic acid

40. Processes of the Digestive System
 Ingestion – getting food into the mouth
 Propulsion – moving foods from one region of the
digestive system to another
 Peristalsis – alternating waves of contraction
 Segmentation – moving materials back and forth to aid in
mixing

41. Processes of the Digestive System
 Mechanical digestion
 Mixing of food in the mouth by the tongue
 Churning of food in the stomach
 Segmentation in the small intestine
 Chemical Digestion
 Enzymes break down food molecules into their
building blocks
 Each major food group uses different enzymes
 Carbohydrates are broken to simple sugars
 Proteins are broken to amino acids
 Fats are broken to fatty acids and alcohols

42. Processes of the Digestive System
 Absorption
End products of digestion are absorbed in
the blood or lymph
Food must enter mucosal cells and then
into blood or lymph capillaries
 Defecation
Elimination of indigestible substances as
feces

44. DISORDERS OF THE
GASTROINTESTINAL SYSTEM

45. Disorders of the upper GI system
Disorders affecting Ingestion
• ANOREXIA: lack of appetite, could be from emotional or
physical factors
• lab tests may be done to assess nutritional status
• Medical treatment:supplements may be ordered, TPN or
enteral feedings
• Nursing Interventions:
– oral hygiene, clean room, determine cause of
nausea and treat, include family and
friends(socialization), respect likes and dislikes,
education

46. STOMATITIS
• Inflammation of the oral mucosa (mouth)
• Causes: trauma, organisms, irritants, nutritional
deficiency, diseases, chemotherapy
• S/S: swelling, pain, ulcerations, excessive salivation,
halitosis, sore mouth
• Treatment:
• pain relief, removal of causative factor, oral hygiene,
medications, soft bland diet

47. GINGIVITIS
• Inflammation of the gums
• Causes: poor oral hygiene, poorly fitting
dentures, nutritional deficiency
• S/S: red, swollen, bleeding gums, painful
• Treatment: dental hygiene, prevention of
complications

48. HERPES SIMPLEX TYPE 1
• Infection affecting the lips and mucous membranes
of the mouth
• Causes: Herpes simplex virus
• S/S: Vesicles on the mouth, nose or lips, malaise,
edema of surrounding area
• Treatment: Antiviral medication(Zovirax), analgesics,
symptomatic relief
• Nsg Interventions: Administer meds, keep lesions
dry, provide symptomatic relief

49. LEUKOPLAKIA
• Abnormal thickening and whitening of the
epithelium of the mucous membranes of the cheeks
and tongue
• Causes: Chronic irritation
• S/S: Thickened white or reddish lesions on the
mucous membrane, lesions can not be rubbed off
• Treatment: May be surgically removed or treated
with chemotherapy, meticulous oral hygiene
• Interventions: Assess mouth frequently, assist with
oral hygiene, discuss removal of sources of irritation

50. ORAL CANCER
• Malignant lesions may develop on the lips, oral cavity, tongue
and pharynx. Generally squamous cell carcinomas
• Causes: high alcohol consumption, tobacco use, external
irritants
• S/S: Leukoplakia, swelling, edema, numbness, pain
• Diagnosis: biopsy
• Treatment:
– Surgery
– Radiation or chemotherapy
• depends on the size and location and the lesion
• Interventions: consult MD for special mouth care, monitor
respiratory status, keep HOB elevated, administer pain med,
assess ability to swallow and talk, assess for infection at
incision site, education.

51. ESOPHAGITIS
• Inflammation or irritation of the esophagus
• Causes: Reflux of stomach contents, irritants, fungal
infections, trauma, malignancy, intubation
• S/S: heartburn, pain, dysphagia
• Treatment: treat underlying cause
• Interventions: soft bland diet, administer meds,
elevate HOB, observe for complications

52. NAUSEA AND VOMITING
• Nausea: unpleasant sensation usually preceding vomiting,
may have abdominal pain, pallor, sweating, clammy skin
• Causes: irritating food, infection, radiation, drugs,
hormonal changes, surgery, inner ear disorders, distention
of the GI tract
• Vomiting: forceful expulsions of stomach contents through
the mouth. Occurs when vomiting reflex in the brain is
stimulated.
• Projectile vomiting- is forceful ejection of stomach
contents.
• Regurgitation- gentle ejection of stomach contents without
nausea or retching

53. Complications and Treatment
• May lead to dehydration, metabolic
alkalosis, aspiration
• Treatment: Antiemetics( Phenergan,
Dramamine, Scopolamine patch Reglan), IV
fluids, NG tube, TPN
• Nursing care: through assessment, keep
patient comfortable, offer liquids, position
on side, suction setup in the room

54. GASTRITIS
• Inflammation of the lining of the stomach
• ACUTE: excessive intake of food or alcohol.
Food poisoning, chemical irritation
• CHRONIC: repeated episodes of acute, H Pylori

55. Signs/Symptoms and Complications
• Nausea, vomiting, feeling of fullness, pain in
stomach, indigestion. With chronic may have
only mild indigestion
• changes in stomach lining with decrease in
acid and intrinsic factor
( high risk for pernicious anemia)

56. Treatment
• Treat symptoms, and fluid replacement
• Medications: antacids, H2 receptor blockers, B 12
injections, corticosteroids analgesics, antibiotics if H
Pylori
• bland diet, frequent meals
• Eliminate the cause
• surgical intervention
• BEST DIAGNOSIS IS GASTROSOPY & BIOPSY

57. PEPTIC ULCER
• Loss of tissue from the lining of the digestive
tract. May be acute or chronic.
• Classified as gastric or duodental (stress-
develop 24-48hr. After event)
• CAUSES: drugs, stress, heavy alcohol and
tobacco use, infection (H .pylori bacteria)
Conditions that cause high gastric acid
concentration

58. TREATMENT
• Drug therapy
– Antacids
– H2 RECEPTOR BLOCKERS
– ANTICHOLINERGICS-Pro-Banthine, Robinul, Bentyl
– SUCRALFATE- Carafate
– Antibiotics –Flagyl, tetracycline, Biaxin
• treatment goals- relieve symptoms, promote healing,
prevent complications and recurrence

59. STOMACH CANCER
• Rare(25,000/yr.), common in males, African American, over
70 and low socioeconomic status. 60% decrease in past 40
yrs.
• No S/S in early stages
• Late stages S/S: N/V, ascities, liver enlargement, abd. Mass
• Mets to bone and lung
• 10% survival rate after 5 yrs.
• Risk factors: pernicious anemia, chronic gastritis, cigarette
smoking, diet high in starch, salt, salted meat, pickled
foods, nitrates
• Treatment: surgery/ chemotherapy/ radiation
– subtotal gastrectomy, total gastrectomy

60. OBESITY
• Increase in body weight, 20% over ideal,
caused by excessive fat. Morbid obesity twice
ideal
• Causes: heredity, body build, metabolism,
psychosocial factors. Calorie intake exceeds
demands.
•

61. Treatment and nursing care
• Weight reduction diet
• drug therapy, mainly Amphetamines
• Surgical procedures:
– Liposuction
– Lipectomy
– Jaw wiring
– Intragastric balloon
– Gastric bypass
– gastroplasty
– jejunoileal bypass
• Nursing care-assessment, diet monitoring, education

62. DIRRHOEA
• The passage of loose liquid stools with
increased frequency, associated with
cramping, abd, pain
• Causes; (many), foods, allergies, infections,
stress, fecal impaction, tube feedings,
medications
• Complications- usually temporary/ can be
dehydration, malnutrition

63. Treatment/Nursing care
• Treatment; GI rest, antidiarrheal
drugs(Lomotil, Imodium, Kaolin, Aluminum
hydroxide)
• Nursing Care: help determine cause, assessVS,
weight, skin turgor, abdominal destention,
perianal irritation, skin integrity

64. CONSTIPATION
• HARD DRY INFREQUENT STOOLS PASSED WITH
DIFFICULTY
• Causes: (many),inactivity, ignored urge,
drugs,age related changes
• Complications: straining (Valsalva maneuver)
and fecal impaction

65. Treatment/Nursing care
• Laxatives, suppositorys, enemas for prompt
results
• stool softeners, increase fluids,dietary fiber
• Nursing care: assessment, monitor fluids and
diet, education, check for impaction

66. Thank
you…