DIGESTIVE SYSTEM Power point presentation

Digestive system anatomy

1. Essentials of Human Anatomy & Physiology
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Seventh Edition
Elaine N. Marieb
Chapter 14
The Digestive System
and Body Metabolism

2. The Digestive System and Body The Digestive System and Body
MetabolismMetabolism
Slide 14.1Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Digestion
Breakdown of ingested food
Absorption
Passage of nutrients into the blood
Metabolism
Production of cellular energy (ATP)

3. Organs of the Digestive SystemOrgans of the Digestive System
Slide 14.2aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Two main groups
Alimentary canal – continuous coiled hollow
tube
Accessory digestive organs

4. Organs of the Digestive SystemOrgans of the Digestive System
Slide 14.2bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.1

5. Organs of the Alimentary CanalOrgans of the Alimentary Canal
Slide 14.3Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Mouth
Pharynx
Esophagus
Stomach
Small intestine
Large intestine
Anus

6. Mouth (Oral Cavity) AnatomyMouth (Oral Cavity) Anatomy
Slide 14.4Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Lips (labia) – protect
the anterior opening
Cheeks – form the
lateral walls
Hard palate – forms
the anterior roof
Soft palate – forms
the posterior roof
Uvula – fleshy
projection of the
soft palate
Figure 14.2a

7. Mouth (Oral Cavity) AnatomyMouth (Oral Cavity) Anatomy
Slide 14.5Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Vestibule – space
between lips
externally and teeth
and gums internally
Oral cavity – area
contained by the
teeth
Tongue – attached
at hyoid and styloid
processes of the
skull, and by the
lingual frenulum
Figure 14.2a

8. Mouth (Oral Cavity) AnatomyMouth (Oral Cavity) Anatomy
Slide 14.6Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Tonsils
Palatine tonsils
Lingual tonsil
Figure 14.2a

9. Processes of the MouthProcesses of the Mouth
Slide 14.7Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Mastication (chewing) of food
Mixing masticated food with saliva
Initiation of swallowing by the tongue
Allowing for the sense of taste

10. Pharynx AnatomyPharynx Anatomy
Slide 14.8Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Nasopharynx –
not part of the
digestive system
Oropharynx –
posterior to oral
cavity
Laryngopharynx –
below the oropharynx
and connected to
the esophagus
Figure 14.2a

11. Pharynx FunctionPharynx Function
Slide 14.9Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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)

12. EsophagusEsophagus
Slide 14.10Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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)

13. Layers of Alimentary Canal OrgansLayers of Alimentary Canal Organs
Slide 14.11aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Mucosa
Innermost layer
Moist membrane
Surface epithelium
Small amount of connective tissue
(lamina propria)
Small smooth muscle layer

14. Layers of Alimentary Canal OrgansLayers of Alimentary Canal Organs
Slide 14.11bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Submucosa
Just beneath the mucosa
Soft connective tissue with blood vessels,
nerve endings, and lymphatics

15. Layers of Alimentary Canal OrgansLayers of Alimentary Canal Organs
Slide 14.12Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Muscularis externa – smooth muscle
Inner circular layer
Outer longitudinal layer
Serosa
Outermost layer – visceral peritoneum
Layer of serous fluid-producing cells

16. Layers of Alimentary Canal OrgansLayers of Alimentary Canal Organs
Slide 14.13Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.3

17. Stomach AnatomyStomach Anatomy
Slide 14.15aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Located on the left side of the
abdominal cavity
Food enters at the cardioesophageal
sphincter

18. Stomach AnatomyStomach Anatomy
Slide 14.15bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Regions of the stomach
Cardiac region – near the heart
Fundus
Body
Phylorus – funnel-shaped terminal end
Food empties into the small intestine at
the pyloric sphincter

19. Stomach AnatomyStomach Anatomy
Slide 14.16aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Rugae – internal folds of the mucosa
External regions
Lesser curvature
Greater curvature

20. Stomach AnatomyStomach Anatomy
Slide 14.16bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Layers of peritoneum attached to the
stomach
Lesser omentum – attaches the liver to the
lesser curvature
Greater omentum – attaches the greater
curvature to the posterior body wall
Contains fat to insulate, cushion, and
protect abdominal organs

21. Stomach AnatomyStomach Anatomy
Slide 14.17Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.4a

22. Stomach FunctionsStomach Functions
Slide 14.18Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Acts as a storage tank for food
Site of food breakdown
Chemical breakdown of protein begins
Delivers chyme (processed food) to the
small intestine

23. Specialized Mucosa of the Specialized Mucosa of the
StomachStomach
Slide 14.19Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Simple columnar epithelium
Mucous neck cells – produce a sticky
alkaline mucus
Gastric glands – secrete gastric juice
Chief cells – produce protein-digesting
enzymes (pepsinogens)
Parietal cells – produce hydrochloric acid
Endocrine cells – produce gastrin

24. Structure of the Stomach MucosaStructure of the Stomach Mucosa
Slide 14.20aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Gastric pits formed by folded mucosa
Glands and specialized cells are in the
gastric gland region

25. Structure of the Stomach MucosaStructure of the Stomach Mucosa
Slide 14.20bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.4b, c

26. Small IntestineSmall Intestine
Slide 14.21Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The body’s major digestive organ
Site of nutrient absorption into the blood
Muscular tube extending form the
pyloric sphincter to the ileocecal valve
Suspended from the posterior
abdominal wall by the mesentery

27. Subdivisions of the Small IntestineSubdivisions of the Small Intestine
““Dogs Just Itch!Dogs Just Itch!
Slide 14.22Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Duodenum
Attached to the stomach
Curves around the head of the pancreas
Jejunum
Attaches anteriorly to the duodenum
Ileum
Extends from jejunum to large intestine

28. Chemical Digestion in the Small Chemical Digestion in the Small
IntestineIntestine
Slide 14.23aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Source of enzymes that are mixed with
chyme
Intestinal cells
Pancreas
Bile enters from the gall bladder

29. Chemical Digestion in the Small Chemical Digestion in the Small
IntestineIntestine
Slide 14.23bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.6

30. Villi of the Small IntestineVilli of the Small Intestine
Slide 14.24Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Fingerlike
structures formed
by the mucosa
Give the small
intestine more
surface area
Figure 14.7a

31. Microvilli of the Small IntestineMicrovilli of the Small Intestine
Slide 14.25Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Small projections of the
plasma membrane
Found on absorptive cells
Figure 14.7c

32. Structures Involved in Absorption Structures Involved in Absorption
of Nutrientsof Nutrients
Slide 14.26Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Absorptive cells
Blood capillaries
Lacteals (specialized
lymphatic capillaries)
Figure 14.7b

33. Folds of the Small IntestineFolds of the Small Intestine
Slide 14.27Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Called circular folds or plicae circulares
Deep folds of the mucosa and
submucosa
Do not disappear when filled with food
The submucosa has Peyer’s patches
(collections of lymphatic tissue)

34. Digestion in the Small IntestineDigestion in the Small Intestine
Slide 14.57aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Enzymes from the brush border
Break double sugars into simple sugars
Complete some protein digestion
Pancreatic enzymes play the major
digestive function
Help complete digestion of starch
(pancreatic amylase)
Carry out about half of all protein digestion
(trypsin, etc.)

35. Digestion in the Small IntestineDigestion in the Small Intestine
Slide 14.57bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Pancreatic enzymes play the major
digestive function (continued)
Responsible for fat digestion (lipase)
Digest nucleic acids (nucleases)
Alkaline content neutralizes acidic chyme

36. Absorption in the Small IntestineAbsorption in the Small Intestine
Slide 14.59Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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

37. Propulsion in the Small IntestinePropulsion in the Small Intestine
Slide 14.60Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Peristalsis is the major means of moving
food
Segmental movements
Mix chyme with digestive juices
Aid in propelling food

38. Large IntestineLarge Intestine
Slide 14.28Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Larger in diameter, but shorter than the
small intestine
Frames the internal abdomen

39. Large IntestineLarge Intestine
Slide 14.28Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.8

40. Functions of the Large IntestineFunctions of the Large Intestine
Slide 14.29Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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

41. Structures of the Large IntestineStructures of the Large Intestine
Slide 14.30aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Cecum – saclike first part of the large
intestine
Appendix
Accumulation of lymphatic tissue that
sometimes becomes inflamed
(appendicitis)
Hangs from the cecum

42. Structures of the Large IntestineStructures of the Large Intestine
Slide 14.30bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Colon
Ascending
Transverse
Descending
S-shaped sigmoidal
Rectum
Anus – external body opening

43. Structures of the Large IntestineStructures of the Large Intestine
Slide 14.30bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Colon
Ascending
Transverse
Descending
S-shaped sigmoidal
Rectum
Anus – external body opening

44. Food Breakdown and Absorption in Food Breakdown and Absorption in
the Large Intestinethe Large Intestine
Slide 14.61Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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

45. Propulsion in the Large IntestinePropulsion in the Large Intestine
Slide 14.62Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Sluggish peristalsis
Mass movements
Slow, powerful movements
Occur three to four times per day
Presence of feces in the rectum causes
a defecation reflex
Internal anal sphincter is relaxed
Defecation occurs with relaxation of the
voluntary (external) anal sphincter

46. Accessory Digestive OrgansAccessory Digestive Organs
Slide 14.32Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Salivary glands
Teeth
Pancreas
Liver
Gall bladder

47. Salivary GlandsSalivary Glands
Slide 14.33Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Saliva-producing glands
Parotid glands – located anterior to ears
Submandibular glands
Sublingual glands

48. SalivaSaliva
Slide 14.34Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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

49. TeethTeeth
Slide 14.35aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The role is to masticate (chew) food
Humans have two sets of teeth
Deciduous (baby or milk) teeth
20 teeth are fully formed by age two

50. TeethTeeth
Slide 14.35bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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

51. Classification of TeethClassification of Teeth
Slide 14.36aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Incisors
Canines
Premolars
Molars

52. Classification of TeethClassification of Teeth
Slide 14.36bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.9

53. Regions of a ToothRegions of a Tooth
Slide 14.37aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Crown – exposed
part
Outer enamel
Dentin
Pulp cavity
Neck
Region in contact
with the gum
Connects crown to
root
Figure 14.10

54. Regions of a ToothRegions of a Tooth
Slide 14.37bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Root
Periodontal
membrane
attached to the
bone
Root canal carrying
blood vessels and
nerves
Figure 14.10

55. PancreasPancreas
Slide 14.38Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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

56. LiverLiver
Slide 14.39Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Largest gland in the body
Located on the right side of the body
under the diaphragm
Consists of four lobes suspended from
the diaphragm and abdominal wall by
the falciform ligament
Connected to the gall bladder via the
common hepatic duct

57. BileBile
Slide 14.40Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Produced by cells in the liver
Composition
Bile salts
Bile pigment (mostly bilirubin from the
breakdown of hemoglobin)
Cholesterol
Phospholipids
Electrolytes

58. Role of the Liver in MetabolismRole of the Liver in Metabolism
Slide 14.77Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Several roles in digestion
Detoxifies drugs and alcohol
Degrades hormones
Produce cholesterol, blood proteins
(albumin and clotting proteins)
Plays a central role in metabolism

59. Gall BladderGall Bladder
Slide 14.41Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Sac found in hollow fossa of liver
Stores bile from the liver by way of the
cystic duct
Bile is introduced into the duodenum in
the presence of fatty food
Gallstones can cause blockages

60. Processes of the Digestive SystemProcesses of the Digestive System
Slide 14.42aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Ingestion – getting food into the mouth
Propulsion – moving foods from one
region of the digestive system to
another

61. Processes of the Digestive SystemProcesses of the Digestive System
Slide 14.42bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Peristalsis – alternating
waves of contraction
Segmentation – moving
materials back and forth
to aid in mixing
Figure 14.12

62. Processes of the Digestive SystemProcesses of the Digestive System
Slide 14.43Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Mechanical digestion
Mixing of food in the mouth by the tongue
Churning of food in the stomach
Segmentation in the small intestine

63. Processes of the Digestive SystemProcesses of the Digestive System
Slide 14.44Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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

64. Processes of the Digestive SystemProcesses of the Digestive System
Slide 14.45Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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

65. Processes of the Digestive SystemProcesses of the Digestive System
Slide 14.46Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 14.11

66. Control of Digestive ActivityControl of Digestive Activity
Slide 14.47aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Mostly controlled by reflexes via the
parasympathetic division
Chemical and mechanical receptors are
located in organ walls that trigger
reflexes

67. Control of Digestive ActivityControl of Digestive Activity
Slide 14.47bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Stimuli include:
Stretch of the organ
pH of the contents
Presence of breakdown products
Reflexes include:
Activation or inhibition of glandular
secretions
Smooth muscle activity

68. Nutrition - Take a Class!Nutrition - Take a Class!
Slide 14.63Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Nutrient – substance used by the
body for growth, maintenance, and
repair
Categories of nutrients
Carbohydrates: simple sugars, starches,
fiber
Lipids: triglycerides, phospholipids, fatty
acids
Proteins: amino acids
Vitamins
Mineral
Water

69. Body Energy BalanceBody Energy Balance
Slide 14.83Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Energy intake = total energy output
(heat + work + energy storage)
Energy intake is liberated during food
oxidation
Energy output
Heat is usually about 60%
Storage energy is in the form of fat or
glycogen