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