Transcript Anatomy & Physiology SIXTH EDITION Chapter 24, part 1 The Digestive System PowerPoint® Lecture Slide Presentation prepared by Dr.

Anatomy & Physiology
SIXTH EDITION
Chapter 24, part 1
The Digestive System
PowerPoint® Lecture Slide Presentation prepared by
Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Frederic H. Martini
Fundamentals of
Learning Objectives
• Identify the organs of the digestive system and
their major functions
• Outline the mechanisms that regulate digestion
• Describe the anatomy of the organs and accessory
organs of the digestive system
• Discuss the functions of the major structures and
regions of the digestive system and discuss the
regulation of their activities
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Learning Objectives
• Explain the significance of the large intestine in
the absorption of nutrients
• Describe the events involved in the digestion of
organic and inorganic nutrients
• Summarize the effects of the aging process on the
digestive system
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SECTION 24-1
The Digestive System
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The Digestive system includes:
• The muscular digestive tract
• Various accessory organs
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Figure 24.1 The Components of the Digestive
System
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Figure 24.1
Functions of the digestive system
• Ingestion
• Mechanical processing
• Digestion
• Secretion
• Absorption
• Excretion
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The digestive system organs and the peritoneum
• Mesenteries
• Sheets of serous membranes that support
portions of the digestive tract
• Greater omentum lies anterior to abdominal
viscera
• Provides padding, protection, insulation,
and energy reserves
• Lesser omentum
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Figure 24.2 Mesenteries
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Figure 24.2a
Figure 24.2 Mesenteries
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Figure 24.2b
Figure 24.2 Mesenteries
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Figure 24.2c
Figure 24.2 Mesenteries
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Figure 24.2d
Histological organization of the digestive tract
• Mucosa lines digestive tract (mucous epithelium)
• Moistened by glandular secretions
• Lamina propria and epithelium form mucosa
• Submucosa
• Layer of dense irregular connective tissue
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Histological organization of the digestive tract
• Muscularis externa
• Smooth muscle arranged in circular and
longitudinal layers
• adventitia
• Serosa
• Serous membrane covering most of the
muscularis externa
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Figure 24.3 The Structure of the Digestive Tract
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Figure 24.3
Movement of digestive materials
• Visceral smooth muscle shows rhythmic cycles of
activity
• Pacemaker cells
• Peristalsis
• Waves that move a bolus
• Segmentation
• Churn and fragment a bolus
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Figure 24.4 Peristalsis
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Figure 24.4
Control of the digestive system
• Movement of materials along the digestive tract is
controlled by:
• Neural mechanisms
• Parasympathetic and local reflexes
• Hormonal mechanisms
• Enhance or inhibit smooth muscle
contraction
• Local mechanisms
• Coordinate response to changes in pH or
chemical stimuli
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Figure 24.5 The Regulation of Digestive
Activities
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Figure 24.5