Principles of Anatomy
and Physiology
Thirteenth Edition
Gerard J. Tortora • Bryan H. Derrickson
Chapter 24
The Digestive System
Copyright © 2012 by John Wiley & Sons, Inc.
Parotid gland
(salivary gland)
Submandibular gland
(salivary gland)
Mouth (oral cavity)
contains teeth and tongue
Sublingual gland
(salivary gland)
Pharynx
Esophagus
Liver
Duodenum
Gallbladder
Jejunum
Ascending colon
Ileum
Cecum
Appendix
Stomach
Pancreas
Transverse colon
Descending colon
Sigmoid colon
Rectum
Anal canal
Anus
(a) Right lateral view of head and neck and anterior view of trunk
SUPERIOR
Diaphragm
Falciform
ligament
Stomach
Liver
Transverse colon
Gallbladder
Ascending colon
Descending colon
Cecum
Jejunum
Ileum
(b) Anterior view
Duct of gland outside
tract (such as
pancreas)
Submucosal plexus
(plexus of Meissner)
Gland in
mucosa
Mucosa-associated
lymphatic tissue
(MALT)
Lumen
Mesentery
Vein
Glands in
submucosa
Artery
Nerve
MUCOSA:
Epithelium
Lamina propria
Muscularis
mucosae
Myenteric plexus
(plexus of Auerbach)
SUBMUCOSA
MUSCULARIS:
Circular muscle
Longitudinal muscle
SEROSA:
Areolar connective tissue
Epithelium
ENTERIC NERVOUS SYSTEM
To ANS and
CNS neurons
Myenteric plexus
Interneuron
Submucosal plexus
Motor neuron
Motor neuron
Longitudinal and
circular smooth muscle
layers of the muscularis
Sensory neuron
Mucosal epithelium
Diaphragm
Liver
LESSER OMENTUM
Pancreas
Stomach
MESOCOLON
Duodenum
MESENTERY
Transverse colon
GREATER OMENTUM
Jejunum
Ileum
PARIETAL PERITONEUM
Sigmoid colon
Uterus
VISCERAL PERITONEUM
Urinary bladder
PERITONEAL CAVITY
Rectum
Pubic symphysis
POSTERIOR
ANTERIOR
(a) Midsagittal section showing the peritoneal folds
Midsagittal
plane
FALCIFORM LIGAMENT
Liver
Stomach
Transverse colon
GREATER OMENTUM
Urinary bladder
(b) Anterior view
Gallbladder (reflected
upward)
LESSER OMENTUM
Liver
(reflected upward)
Stomach
Duodenum
Transverse
colon
Descending colon
Ascending
colon
Sigmoid colon
(c) Lesser omentum, anterior view
(liver and gallbladder lifted)
GREATER OMENTUM
(reflected upward)
Transverse colon
Jejunum (pulled laterally)
MESENTERY
Descending colon
Ileum (pulled laterally)
Sigmoid colon
Urinary bladder
(d) Anterior view (greater omentum lifted
and small intestine reflected to right side)
SUPERIOR
Lungs
Heart
Diaphragm
Right lobe of liver
FALCIFORM LIGAMENT
Left lobe of liver
Stomach
GREATER OMENTUM
(e) Anterior view
Superior lip (lifted upward)
Superior labial frenulum
Gingivae (gums)
Palatoglossal arch
Hard palate
Fauces
Soft palate
Palatopharyngeal arch
Uvula
Cheek
Palatine tonsil
(between the arches)
Molars
Tongue (lifted upward)
Lingual frenulum
Opening of duct of
submandibular gland
Premolars
Cuspid (canine)
Incisors
Oral vestibule
Gingivae (gums)
Inferior labial frenulum
Inferior lip (pulled down)
Anterior view
Parotid duct
Zygomatic arch
PAROTID GLAND
Opening of parotid duct
(near second maxillary molar)
Second maxillary molar tooth
Tongue (raised in mouth)
Lingual frenulum
Sublingual ducts
Lesser sublingual duct
Submandibular duct
SUBMANDIBULAR GLAND
SUBLINGUAL GLAND
Mylohyoid muscle
(a) Location of salivary glands
Mucous acini
Serous acini
LM 240x
(b) Portion of submandibular gland
Sagittal
plane
Enamel
Dentin
CROWN
Gingival sulcus
Gingiva (gum)
Pulp in pulp
cavity
NECK
Cementum
Root canal
Alveolar bone
ROOT
Periodontal
ligament
Apical foramen
Nerve
Blood supply
Sagittal section of a mandibular (lower) molar
Central incisor(8–12 mo.)
Lateral incisor(12–24 mo.)
Cuspid or canine (16–24 mo.)
D E FG
H
C
B
I
A
J
First molar (12–16 mo.)
Second molar (24–32 mo.)
Upper Teeth
Lower Teeth
Second molar (24–32 mo.)
T
K
S
L
R
M
Q P ON
First molar (12–16 mo.)
Cuspid or canine (16–24 mo.)
Lateral incisor(12–15 mo.)
Central incisor(6–8 mo.)
(a) Deciduous (primary) dentition; teeth are designated by letters
(with times of eruption)
Central incisor (7–8 yr.)
Lateral incisor(8–9 yr.)
7 8
6
5
4
Cuspid or canine (11–12 yr.)
9 1011
12
13
3
First premolar or bicuspid (9–10 yr.)
Second premolar or bicuspid
(10–12 yr.)
14
2
15
Upper Teeth
1
First molar (6–7 yr.)
16
Second molar (12–13 yr.)
Third molar or wisdom tooth
(17–21 yr.)
Lower Teeth
32
17
31
Third molar or wisdom tooth
(17–21 yr.)
18
30
Second molar (11–13 yr.)
29
28
2726
19
First molar (6–7 yr.)
20
21
Second premolar or bicuspid
(11–12 yr.)
22
252423
First premolar or bicuspid (9–10 yr.)
(b) Permanent (secondary)
dentition; teeth are designated by
numbers (with times of eruption)
Cuspid or canine (9–10 yr.)
Lateral incisor(7–8 yr.)
Central incisor(7–8 yr.)
Lumen of esophagus
Mucosa:
Nonkeratinized
stratified squamous
epithelium
Lamina propria
Muscularis mucosae
Transverse plane
Submucosa
Muscularis
(circular layer)
Muscularis
(longitudinal layer)
Adventitia
LM
20x
Wall of the esophagus
Nasopharynx
Hard palate
Soft palate
Bolus
Uvula
Oropharynx
Tongue
Epiglottis
Laryngopharynx
Larynx
Esophagus
(a) Position of structures before swallowing
(b) During pharyngeal stage
of swallowing
Esophagus
Relaxed muscularis
Circular muscles
contract
Longitudinal muscles
contract
Relaxed muscularis
Lower esophageal
sphincter
Bolus
Stomach
(c) Anterior view of frontal sections of peristalsis in esophagus
Esophagus
Lower esophageal
sphincter
FUNDUS
Serosa
CARDIA
Muscularis:
Longitudinal layer
BODY
Circular layer
Lesser curvature
PYLORUS
Oblique layer
Greater curvature
Duodenum
Pyloric
sphincter
Rugae of mucosa
PYLORIC ANTRUM
PYLORIC CANAL
(a) Anterior view of regions of stomach
Esophagus
Duodenum
PYLORUS
Pyloric sphincter
PYLORIC CANAL
Lesser
curvature
PYLORIC ANTRUM
FUNDUS
CARDIA
BODY
Rugae of mucosa
Greater curvature
(b) Anterior view of internal anatomy
Lumen of stomach
Gastric pits
Surface mucous
cell
Lamina propria
Lymphatic nodule
Mucous neck cell
Parietal cell
Chief cell
Gastric gland
G cell
Muscularis mucosae
MUCOSA
SUBMUCOSA
Lymphatic vessel
MUSCULARIS
Venule
Arteriole
Oblique layer of muscle
Circular layer of muscle
SEROSA
Myenteric plexus
Longitudinal layer
of muscle
(a) Three-dimensional view of layers of stomach
Gastric pit
Surface mucous cells
Gastric
pit
Lamina
SEM
40x
propria
Stomach mucosa
Gastric
glands
Muscularis
mucosae
Surface mucous cell
(secretes mucus)
Mucous neck cell
(secretes mucus)
Parietal cell (secretes
hydrochloric acid
and intrinsic factor)
Chief cell (secretes
pepsinogen and
gastric lipase)
G cell (secretes the
hormone gastrin)
Submucosa
(b) Sectional view of stomach mucosa showing gastric glands and cell types
Gastric pit
Lamina propria
Surface mucous cell
Lumen of
gastric gland
Mucous neck cell
Parietal cell
G cells
Chief cells
Lumen of gastric
gland
LM
(c) Fundic mucosa
180x
Chyme in
stomach lumen
ATP
Blood capillary in
lamina propria
ADP
H+
K+
CA
Cl–
H2O + CO2
H2CO3
H+ + HCO3–
HCO3–
HCO3–
Alkaline
tide
Cl–
Parietal cell
Apical
membrane
Basolateral
membrane
Interstitial
fluid
Key:
Proton pump
(H+/K+ ATPase)
CA
Carbonic anhydrase
Diffusion
K+ (potassium ion)
channel
Cl– (chloride ion)
channel
HCO3–
HCO3– /Cl– antiporter
Cl–
Lumen of stomach
Interstitial fluid
Parietal cell
Acetylcholine
(ACh)
ACh receptor
HCl
secretion
Gastrin
Gastrin receptor
Histamine
Apical
membrane
Histamine
receptor
Basolateral
membrane
Falciform ligament
Diaphragm
Right lobe of liver
Right hepatic
duct
Coronary ligament
Left lobe of liver
Left hepatic duct
Common hepatic duct
Gallbladder:
Neck
Body
Round ligament
Cystic duct
Fundus
Common bile duct
Pancreas
Tail
Body
Duodenum
Pancreatic duct (duct of
Wirsung)
Accessory duct
(duct of Santorini)
Head
Hepatopancreatic ampulla
(ampulla of Vater)
Uncinate process
Jejunum
(a) Anterior view
Common bile duct
Pancreatic duct
(duct of Wirsung)
Hepatopancreatic ampulla
(ampulla of Vater)
Mucosa of
duodenum
Major
duodenal
papilla
Sphincter of the hepatopancreatic
ampulla (sphincter of Oddi)
(b) Details of hepatopancreatic ampulla
Right hepatic
duct
Left hepatic
duct
Common hepatic
duct from liver
Cystic duct from
gallbladder
Common bile duct
Pancreatic duct
from pancreas
Key:
Liver
Sphincter
Gallbladder
Pancreas
Duodenum
(c) Ducts carrying bile from liver and gallbladder and
pancreatic juice from pancreas to duodenum
Falciform
ligament
Liver
Diaphragm
Hepatic
bile duct
Spleen
Cystic bile
duct
Tail of pancreas
Gallbladder
Pancreatic duct
(duct of Wirsung)
Common bile
duct
Body of
pancreas
Major
duodenal papilla
Head of
pancreas
Duodenum
(d) Anterior view
SUPERIOR
Duodenum
Tail of pancreas
Common bile
duct
Body of
pancreas
Major
duodenal papilla
Pancreatic duct
(duct of Wirsung)
Head of pancreas
Uncinate process
MEDIAL
LATERAL
(e) Anterior view
Liver
Inferior vena cava
Hepatic artery
Hepatic portal vein
Connective
tissue
Portal triad:
Bile duct
Hepatocyte
Hepatic
laminae
Branch of
hepatic artery
Branch of
hepatic portal vein
Central vein
Hepatic sinusoids
(a) Overview of histological components of liver
Central
vein
To hepatic
vein
Hepatic
sinusoids
Bile canaliculi
Portal triad:
Bile duct
Branch of hepatic
portal vein
Branch of hepatic
artery
Hepatic laminae
Hepatocyte
Stellate
reticuloendothelial
(Kupffer) cell
Connective tissue
Hepatic sinusoid
(b) Details of histological components of liver
Hepatocyte
Central vein
Sinusoid
LM 100x
LM 50x
Portal triad:
Branch of hepatic artery
Bile duct
Branch of hepatic portal vein
LM 150x
(c) Photomicrographs
Central vein
Portal
triad
Hepatic lobule
Portal lobule
Hepatic acinus
(d) Comparison of three units of liver structure and function
Portal triad
Central
vein
Central
vein
Zone 3
Zone 2
Zone 1
(e) Details of hepatic acinus
Oxygenated blood
from hepatic artery
1
Nutrient-rich,
deoxygenated blood from
hepatic portal vein
2
Liver sinusoids
3
Central vein
4
Hepatic vein
5
Inferior vena cava
6
Right atrium of heart
Stomach
DUODENUM
Large
intestine
JEJUNUM
ILEUM
(a) Anterior view of external anatomy
Circular folds
(plicae circulares)
(b) Internal anatomy of jejunum
Circular folds
(plicae circulares)
Circular folds
Villi
Submucosa
(a) Relationship of
villi to circular folds
Circular layer of
muscle
Longitudinal
layer of muscle
Serosa
Lumen of small intestine
Blood
capillary
Lacteal
Villi
Opening of
intestinal gland
Absorptive cell
Goblet cell
Lacteal
Lamina propria
MUCOSA
Enteroendocrine cell
Paneth cell
Lymphatic nodule
Muscularis mucosae
SUBMUCOSA
Arteriole
Venule
Lymphatic vessel
MUSCULARIS
Circular layer of muscle
Myenteric plexus
Longitudinal layer
of muscle
(b) Three-dimensional view of layers of the small intestine showing villi
SEROSA
Microvilli
Absorptive cell
(absorbs nutrients)
Blood
capillary
Lacteal
Mucosa
Goblet cell
(secretes mucus)
Lamina
propria
Intestinal
gland
Enteroendocrine cell
(secretes the hormones
secretin,
cholecystokinin, or GIP)
Muscularis
mucosae
Arteriol
Submucosa
Venule
Paneth cell (secretes
lysozyme and is capable
of phagocytosis)
Lymphatic
vessel
Muscularis
(c) Enlarged villus showing lacteal,
capillaries, intestinal glands, and cell type
Villi
Lumen of duodenum
Mucosa
Intestinal glands
Muscularis mucosae
Submucosa
Duodenal gland
Muscularis
LM 45x
(a) Wall of duodenum
Villi
Lumen of duodenum
Brush border
Simple columnar
epithelium
Goblet cell
Absorptive cell
Duodenum
Lamina propria
Intestinal glands
LM 160x
(b) Several villi from duodenum
Lumen of ileum
Villus
Solitary lymphatic
nodule
Submucosa
Muscularis
LM 14x
(c) Lymphatic nodules in ileum
Microvilli
Brush border
Simple columnar
epithelial cell
TEM 46,800x
(d) Several microvilli from duodenum
Glucose and
galactose
Fructose
Secondary active
transport with Na+
Facilitated
diffusion
Facilitated
diffusion
Amino acids
Active transport or
secondary active
transport with Na+
Dipeptides
Tripeptides
Small short-chain
fatty acids
To blood
capillary of a
villus
Amino acids
Diffusion
Secondary active
transport with H+
Simple diffusion
Large short-chain
and long-chain
fatty acids
Micelle
Monosaccharides
Diffusion
Triglyceride
Simple
diffusion
To lacteal
of a villus
Monoglycerides
Chylomicron
Lumen of small
intestine
Microvilli (brush
border) on apical
surface
Basolateral surface
Epithelial cells
of villus
(a) Mechanisms for movement of nutrients through absorptive epithelial cells of villi
Left subclavian
vein
Villus (greatly enlarged)
Chylomicron
Heart
Liver
Hepatic
portal
vein
Thoracic duct
Small
shortchain
fatty
acid
Blood
capillary
Amino acid
Lacteal
Monosaccharide
Arteriole
Venule
Blood
Lymphatic vessel
Lymph
(b) Movement of absorbed nutrients into blood and lymph
INGESTED AND SECRETED
ABSORBED
Saliva (1 liter)
Ingestion of liquids
(2.3 liters)
Gastric juice
(2 liters)
Bile (1 liter)
Pancreatic juice
(2 liters)
Intestinal juice
(1 liter)
Small intestine
(8.3 liters)
Total ingested
and secreted
= 9.3 liters
Large intestine
(0.9 liters)
Total absorbed
= 9.2 liters
Excreted in feces
(0.1 liter)
Fluid balance in GI tract
TRANSVERSE COLON
Left colic (splenic)
flexure
Right colic
(hepatic) flexure
Teniae coli
ASCENDING
COLON
Teniae
coli
DESCENDING COLON
Ileum
Omental
appendices
Mesoappendix
Haustra
Ileocecal
sphincter
(valve)
CECUM
RECTUM
VERMIFORM APPENDIX
SIGMOID
COLON
ANAL CANAL
ANUS
(a) Anterior view of large intestine showing major regions
Rectum
Anal canal
Internal anal sphincter
(involuntary)
External anal sphincter
(voluntary)
Anus
Anal column
(b) Frontal section of anal canal
Lumen of large intestine
Openings
of intestinal glands
Absorptive cell
Goblet cell
MUCOSA
Intestinal gland
Lamina propria
Lymphatic nodule
Muscularis mucosae
Lymphatic vessel
Arteriole
SUBMUCOSA
MUSCULARIS
Venule
Circular layer of muscle
SEROSA
Myenteric plexus
Longitudinal layer of
muscle
(a) Three-dimensional view of layers of large intestine
Openings of
intestinal glands
Lamina propria
Microvilli
Intestinal gland
Absorptive cell
(absorbs water)
Goblet cell (secretes mucus)
Muscularis
mucosae
Lymphatic
nodule
Submucosa
(b) Sectional view of intestinal glands and cell types
Lumen of large
intestine
Mucosa
Lamina
propria
Intestinal gland
Submucosa
Lymphatic
nodule
Muscularis
mucosae
Muscularis
Serosa
LM 315x
(c) Portion of wall of large intestine
Opening of intestinal gland
Lumen of large intestine
Absorptive cell
Goblet cell
Lamina propria
Intestinal
gland
LM 300x
(d) Details of mucosa of large intestine
Food entering
stomach disrupts
homeostasis by
Increasing
pH of gastric juice
Distention (stretching)
of stomach walls
Receptors
Chemoreceptors
and stretch
receptors in
stomach
detect pH
increase and
distention
Input
Control center
Nerve
impulses
Submucosal plexus
Output
Return to homeostasis
when response brings pH
of gastric juice and
distention of stomach
walls back to normal
(pre-eating status)
Nerve impulses
(parasympathetic)
Effectors
Parietal cells
secrete HCI and
smooth muscle in
stomach wall
contracts more
vigorously
Increase in acidity of
stomach chyme; mixing
of stomach contents;
emptying of stomach
HCI