1. Essentials of Anatomy and Physiology
Fifth edition
Seeley, Stephens and Tate
Chapter 16: Digestive System
Slide 2.1
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

2. Stomach Anatomy “J” shaped flat bag
Located in epigastric, left hypochondriac regions
Food enters through gastroesophageal (cardiac) sphincter
Slide 14.15a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

4. Stomach Anatomy Regions of the stomach
Cardiac region
Fundus
Body
Pylorus – terminal end
Food empties into the small intestine at the pyloric sphincter
Slide 14.15b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

5. Stomach Anatomy Rugae – internal folds of the mucosa External regions
Lesser curvature
Greater curvature
Slide 14.16a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

6. Stomach Anatomy Layers of peritoneum attached to the stomach
Lesser omentum
Greater omentum
Contains fat to insulate, cushion, and protect abdominal organs
Slide 14.16b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

8. Stomach Functions Acts as a storage site for food
Chemical digestion of protein begins
Delivers chyme (processed food) to the small intestine
Slide 14.18
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

9. Specialized Mucosa of the Stomach
Simple columnar epithelium
Gastric glands – secrete gastric juice
Chief cells – produce pepsinogens
Parietal cells – produce hydrochloric acid
Endocrine cells – produce gastrin
Slide 14.19
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

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

12. Small Intestine Site of nutrient absorption Muscular tube ~20’ long
extends from pyloric sphincter to ileocecal valve
Suspended from the posterior abdominal wall by mesentery
Slide 14.21
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

13. Subdivisions of the Small Intestine
Duodenum
Attached to the stomach
Curves around the head of the pancreas
Jejunum
Second portion, ~8’
Ileum
Longest portion, ~10’
Slide 14.22
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

14. Chemical Digestion in the Small Intestine
Enzymes mix with chyme. Come from:
Intestinal cells
Pancreas (also adds HCO3-)
Bile enters from the gall bladder
Slide 14.23a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

15. Chemical Digestion in the Small Intestine
Figure 14.6
Slide 14.23b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

16. Villi of the Small Intestine
Fingerlike structures formed by the mucosa
Provide more surface area
Figure 14.7a
Slide 14.24
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

18. Folds of the Small Intestine
Called circular folds or plicae circulares
Submucosal specialization
has Peyer’s patches
collections of lymphatic tissue
Slide 14.27
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

19. Large Intestine
Larger in diameter, but shorter than the small intestine
~6’ long
Has subdivisions
Named for direction of food movement
Slide 14.28
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

21. Functions of the Large Intestine
Absorption of water
Eliminates indigestible food as feces
Does not participate in digestion
Goblet cells produce mucus for lubrication
Slide 14.29
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

22. Functions of the Large Intestine
Contains many bacteria (mostly E. coli)
Bacteria digest our wastes
Produce vitamins, amino acids
Vits. B, K
We absorb their “wastes”
Slide 14.29
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

23. Structures of the Large Intestine
Cecum – saclike first part
Appendix
Accumulation of lymphatic tissue that may become inflamed (appendicitis)
Hangs from the cecum
Slide 14.30a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

24. Structures of the Large Intestine
Colon
Ascending
Transverse
Descending
Sigmoid (S-shaped)
Rectum
Anus – external body opening
Slide 14.30b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

26. Modifications to the Longitudinal Layer of Muscle
Smooth muscle reduced to three bands (taeniae coli)
Muscle bands are shorter than colon
Walls are formed into pouches called haustra
Slide 14.31
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

28. Organs of the Digestive System
Figure 14.1
Slide 14.2b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

29. Salivary Glands Salivary glands: 3 pairs
Parotid glands – located anterior to ears
Submandibular glands
Sublingual glands
Slide 14.33
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

30. Saliva Mixture of mucus and serous fluids
Helps to form food into a bolus
Contains salivary amylase
starch digestion
Dissolves chemicals for taste buds
We produce ~1 liter/day
Slide 14.34
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

31. Teeth Function to masticate (chew) food Humans have two sets
Deciduous (baby or milk) teeth
20 teeth are fully formed by age two
Slide 14.35a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

32. Teeth
Permanent teeth
Replace deciduous teeth beginning ~6 years of age
A full adult set is 32 teeth
some people do not have wisdom teeth
Slide 14.35b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

33. Classification of Teeth
Incisors (2)
Canines (1)
Premolars (2)
Molars (3)
Same number and type of teeth in each “quadrant” so….
“Dental Formula”:
Slide 14.36a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

34. Classification of Teeth
Figure 14.9
Slide 14.36b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

35. Liver Largest gland in the body Located in right hypochondriac region
Four lobes
Suspended by the falciform ligament
Connected to gall bladder via common hepatic duct
Slide 14.39
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

36. Primary Function of Liver
Produces bile for fat emulsification
Composition: water, plus…
Bile salts
Bile pigment (mostly bilirubin)
Cholesterol
Phospholipids
Electrolytes
Slide 14.40
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

37. Role of the Liver in Metabolism
Final metabolism of most food
Detoxifies drugs and alcohol
Degrades hormones
Produces cholesterol, blood proteins
Regulates distribution of nutrients
Slide 14.77
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

38. Gall Bladder Sac attached to inferior surface of liver
Stores, concentrates bile
Bile enters duodenum in the presence of fatty food
Requires hormonal signals, autonomic innervation
Gallstones can cause blockages
Slide 14.41
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

39. Pancreas Exocrine function: Produces digestive enzymes
Enzymes: secreted into duodenum
Bicarbonate ions: neutralize acidic chyme
Endocrine products of pancreas
Insulin
Glucagon
Slide 14.38
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings