Campbell; Fig.41.12aCampbell; Fig.41.12a
Campbell; Fig.41.12bCampbell; Fig.41.12b
Campbell; Fig.41.12cCampbell; Fig.41.12c
• Highly reliant on digestive system to remain healthy
• Cannot afford to store heavy materials in body
for lengthy period
Rumen&
Reticulum
AbomassumOmassum
FermentationFilter True digestive
stomach
To intestine
pH = 1 - 2
Mouth
Fungi
ProtozoaBacteria
Foregut fermenters:
*
* Both have enlarged, multi-chambered foreguts
*
Hindgut fermenters
cecum
*
* Enlarged hindgut
(a big S. Americanrodent)
Fig. 21.5 One-way digestive tracts
The most primitive
Specialization in different regions
蠑螈 泄殖腔
嗉囊
沙囊
Fig. 21.17 The pancreatic and bile ducts empty into the duodenum
Fig. 21.20 Nitrogenous wastes
Fig. 21.26
Fig. 21.27 Osmoregulation in elasmobranchs
Fig. 21.31 The mammalian urinary system
Examples of modified incisors
Rumen (Punch)
Reticulum (Hardware Stomach or Tripe)
Omasum (manyplies)
Sheep liver fluke
8.8
Figure 14.12
8.9a and b
Figure 14.13
8.11
Figure 14.16
8.12
Figure 14.18
Tapeworm scolex
The scolex is equipped with a combination of suckers The scolex is equipped with a combination of suckers and hooks that enable it to grip onto its host’s and hooks that enable it to grip onto its host’s intestines.intestines.
Hooks
Suckers
8.14
Figure 14.20
8.15
Figure 14.19
8.16
Figure 14.21
Cysticerci in human brain
8.18
Figure 14.24b
Figure 14.24a
Internal structure of female ribbon worm(above).
Nemertean with proboscis extended (right)
8.19
Figure 14.25
Baseodiscus mexicanus a nemertean fromthe Galapagos Islands
8.20
Figure 14.27
Gnathostomula jenneri
• The digestive system of monogastric animals
Anatomy of Digestive System
Anatomy of Digestive System
Anatomy of Digestive System
• Ruminant GI tracts
Anatomy of Digestive System
Anatomy of Digestive System
Anatomy of Digestive System
Structure of Cellulose
Fig. 5.7
Glucose occurs in two conformations, α and β.
In cellulose, every other glucose is “upside down” making it impossible for amylase (enzyme found in animals) to digest it.
Very few animals have evolved the enzyme cellulase, but many microbes have this enzyme.
Figure 14.1
Digestive System Chapter 14
Pharynx• Passageway for food and air• Participates in swallowing
Esophagus• Moves food from pharynx
to stomach
Salivary glands• Saliva moistens food• Bicarbonate maintains pH• Amylase digests starch• Lysozyme inhibits bacteria
ACCESSORY ORGANS:
Liver• Produces bile• Performs various functions
associated with processingand storing nutrients
Pancreas• Secretes digestive enzymes
into small intestine• Secretes bicarbonate into
small intestine to neutralizestomach acid
Gallbladder• Stores and concentrates bile
Mouth• Teeth chew food• Tongue positions and
tastes food
ORGANS:
Appendix• No known digestive function
Stomach• Stores and mixes food• Begins chemical digestion of
protein by enzymes and acid• Regulates delivery to the
small intestine
Anus• Expels undigested material
Rectum• Passageway for feces
Sigmoid colon• Stores feces
Large intestine• Absorbs the last of the water
and nutrients• Stores waste material
Small intestine• Digests proteins, fats,
and carbohydrates• Absorbs most of the water
and nutrients• Secretes digestive hormones
and enzymes
Figure 14.2
Gastrointestinal (GI) Tract Wall
Lumen
Circularlayer
Longitudinallayer
Lymph vessel
Serosa• Connective tissueouter covering• Protects and anchorsthe digestive tract
Mucosa• Mucous membrane layer• Lines the digestive tract
Submucosa• Connective tissue layer• Contains blood vessels, lymph vessels,and nerves
Muscularis• Two layers of smooth muscle• Responsible for motility of thedigestive tract
VeinArteryNerve
Figure 14.3a
Motility: Peristalsis
Figure 14.3b
Motility: Segmentation
Figure 14.5
Salivary Glands
Figure 14.6a
Swallowing
Figure 14.6b
Swallowing
Figure 14.7a–b
Structure of the Stomach Wall
Figure 14.7
The Stomach
Figure 14.8
Peristalsis
Figure 14.9a–b
The Wall of the Small Intestine
Figure 14.9c
The Wall of the Small Intestine
Figure 14.10
Accessory Organs: Aid Digestion and Absorption
Esophagus Liver• Produces bile
(water and electrolytes,cholesterol, bile salts,lecithin, andpigments)
Gallbladder• Stores and
concentrates bile• Delivers bile to the
duodenum via thecommon bile duct
Pancreas• Secretes enzymes
(proteases, amylase,lipase)
• Produces sodiumbicarbonate
• Delivers these products tothe duodenum via ducts
Stomach
Pancreatic duct
Commonbile duct
Duodenum
Figure 14.11
Accessory Organs: Aid Digestion and Absorption
Figure 14.12
Large Intestine
Sigmoid colon
Descendingcolon
External analsphincter(skeletal muscle)
Anus Anal canal
Rectum
Internal analsphincter(smooth muscle)
Appendix
Cecum
Ileocecalvalve
Ascendingcolon
Transversecolon
Smallintestine
Figure 14.13
Absorption of Proteins and Carbohydrates
Figure 14.14
Absorption of Fats
• Digestion• Anatomy• Gastric Secretions• Accessory organs-
– pancreas, liver, gall bladder
• Small Intestine• Large Intestine• Nutrition and Nutrients
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
General Characteristics of the Alimentary Canal A. The alimentary canal is a muscular tube that passes through the body's ventral cavity.
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
< Pancreas A. The pancreas has an exocrine function of
producing pancreatic juice that aids digestion.
3. Cholecystokinin from the wall of the small intestine stimulates the
release of pancreatic juice with abundant digestive enzymes.
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Goblet cells
Large Intestine A. The large intestine absorbs water and electrolytes and forms and stores feces.
CopyrightThe McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Figure 14.15
Nutrients: Utilized or Stored Until Needed
Figure 14.16
Food Guide Pyramid