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Principles of Anatomy and Physiology
Thirteenth Edition
Chapter 24The Digestive System
Copyright © 2012 by John Wiley & Sons, Inc.
Gerard J. Tortora • Bryan H. Derrickson
Mouth (oral cavity)contains teeth and tongue
Sublingual gland(salivary gland)
Pharynx
Stomach
Pancreas
Transverse colon
Descending colon
Sigmoid colon
Rectum
Anal canal
Anus
Parotid gland(salivary gland)
Submandibular gland(salivary gland)
Esophagus
Liver
Duodenum
Gallbladder
Jejunum
Ascending colon
Ileum
Cecum
Appendix
(a) Right lateral view of head and neck and anterior view of trunk
SUPERIOR
Diaphragm
Ileum
Cecum
Ascending colon
Gallbladder
Liver
Falciform ligament
Descending colon
Jejunum
Transverse colon
Stomach
(b) Anterior view
Muscularis mucosae
Duct of gland outside tract (such as pancreas)
Gland in mucosa
Glands in submucosa
Submucosal plexus (plexus of Meissner)
Vein
Artery
Mucosa-associated lymphatic tissue (MALT)
SUBMUCOSA
MUSCULARIS:Circular muscle
Longitudinal muscle
Myenteric plexus (plexus of Auerbach)
SEROSA:Areolar connective tissueEpithelium
Lumen
Mesentery
MUCOSA:Epithelium
Lamina propria
Nerve
Longitudinal and circular smooth muscle layers of the muscularis
ENTERIC NERVOUS SYSTEM
Myenteric plexus
To ANS and CNS neurons
Interneuron
Submucosal plexus
Motor neuron Motor neuron Sensory neuron
Mucosal epithelium
(a) Midsagittal section showing the peritoneal folds
LESSER OMENTUM
MESOCOLON
MESENTERY
GREATER OMENTUM
PARIETAL PERITONEUM
VISCERAL PERITONEUM
PERITONEAL CAVITY
Diaphragm
Liver
Pancreas
Stomach
Duodenum
Transverse colon
Jejunum
Ileum
Sigmoid colon
Uterus
Urinary bladder
Rectum
Pubic symphysis
ANTERIORPOSTERIOR
Midsagittal plane
(b) Anterior view
FALCIFORM LIGAMENT
GREATER OMENTUM
Stomach
Transverse colon
Urinary bladder
Liver
LESSER OMENTUM
Stomach
Duodenum
Descending colon
Sigmoid colonAscending colon
Transverse colon
Liver(reflected upward)
Gallbladder (reflected upward)
(c) Lesser omentum, anterior view(liver and gallbladder lifted)
(d) Anterior view (greater omentum lifted and small intestine reflected to right side)
GREATER OMENTUM (reflected upward)
Descending colon
Jejunum (pulled laterally)
MESENTERY
Urinary bladder
Transverse colon
Sigmoid colon
Ileum (pulled laterally)
(e) Anterior view
Lungs
FALCIFORM LIGAMENT
DiaphragmRight lobe of liver
Stomach
Heart
Left lobe of liver
GREATER OMENTUM
SUPERIOR
Superior lip (lifted upward)
Superior labial frenulum
Gingivae (gums)
Palatoglossal arch
Fauces
Palatopharyngeal arch
Palatine tonsil (between the arches)
Tongue (lifted upward)
Lingual frenulum
Opening of duct of submandibular gland
Inferior labial frenulum
Inferior lip (pulled down)
Gingivae (gums)
Hard palate
Soft palate
Uvula
Cheek
Molars
Premolars
Cuspid (canine)
IncisorsOral vestibule
Anterior view
Parotid duct
Opening of parotid duct (near second maxillary molar)
Second maxillary molar tooth
Tongue (raised in mouth)
Lingual frenulum
Sublingual ducts
Submandibular duct
Mylohyoid muscle
SUBMANDIBULAR GLAND
Zygomatic arch
PAROTID GLAND
Lesser sublingual duct
SUBLINGUAL GLAND
(a) Location of salivary glands
(b) Portion of submandibular gland
240x
Serous acini
Mucous acini
LM
Enamel
Dentin
Gingival sulcus
Gingiva (gum)
Pulp in pulp cavity
Cementum
Root canal
Alveolar bone
Periodontal ligament
Apical foramen
Nerve
Blood supplySagittal section of a mandibular (lower) molar
CROWN
NECK
ROOT
Sagittal plane
First molar (12–16 mo.)
Central incisor(8–12 mo.)
Lateral incisor(12–24 mo.)
Second molar (24–32 mo.)
Second molar (24–32 mo.)
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)
Lower Teeth
Upper Teeth
Cuspid or canine (16–24 mo.)
ABC
D E FGH
IJ
K
LM
NOPQR
S
T
First molar (6–7 yr.)
Central incisor (7–8 yr.)
Lateral incisor(8–9 yr.)
Second molar (12–13 yr.)
Third molar or wisdom tooth(17–21 yr.)
First molar (6–7 yr.)
Cuspid or canine (11–12 yr.)
Lateral incisor(7–8 yr.)
Central incisor(7–8 yr.)
(b) Permanent (secondary) dentition; teeth are designated by numbers (with times of eruption)
Lower Teeth
Upper Teeth
Cuspid or canine (9–10 yr.)
1
2
3
4
567 8 9 10
17
18
19
20
212223242526
Third molar or wisdom tooth(17–21 yr.)
First premolar or bicuspid (9–10 yr.)
Second premolar or bicuspid (10–12 yr.)
Second molar (11–13 yr.)
First premolar or bicuspid (9–10 yr.)
Second premolar or bicuspid(11–12 yr.)
1112
13
14
15
16
2728
29
30
31
32
Wall of the esophagus
Lumen of esophagus
Mucosa:
Submucosa
Muscularis (circular layer)
Muscularis (longitudinal layer)
Adventitia
Nonkeratinizedstratified squamousepithelium
Muscularis mucosae
Lamina propria
Transverse plane
20xLM
Nasopharynx
Bolus
(a) Position of structures before swallowing (b) During pharyngeal stage of swallowing
Hard palate
Soft palate
Uvula
Oropharynx
Epiglottis
Laryngopharynx
Larynx
Esophagus
Tongue
Longitudinal muscles contract
Esophagus
Lower esophageal sphincter
Bolus
Stomach
Relaxed muscularis
Relaxed muscularis
Circular muscles contract
(c) Anterior view of frontal sections of peristalsis in esophagus
PYLORIC ANTRUM
CARDIA
BODY
FUNDUS
Serosa
Muscularis:Longitudinal layer
Circular layer
Oblique layer
Greater curvature
Rugae of mucosa
PYLORIC CANAL
Pyloric sphincter
Duodenum
Esophagus
Lower esophagealsphincter
Lesser curvature
PYLORUS
(a) Anterior view of regions of stomach
PYLORIC CANAL
BODY
Rugae of mucosa
Lesser curvature
(b) Anterior view of internal anatomy
Pyloric sphincter
Duodenum
PYLORUS
PYLORIC ANTRUM
Esophagus
CARDIA
FUNDUS
Greater curvature
Longitudinal layer of muscle
Gastric pits
Surface mucous cellLamina propria
Mucous neck cellParietal cell
Chief cell
Gastric glandG cellLymphatic nodule
Muscularis mucosae
Lymphatic vessel
Venule
Arteriole
Oblique layer of muscle
Circular layer of muscle
Myenteric plexus
MUCOSA
SUBMUCOSA
MUSCULARIS
SEROSA
Lumen of stomach
(a) Three-dimensional view of layers of stomach
G cell (secretes the hormone gastrin)
Gastric glands
Lamina propria
Muscularis mucosae
Mucous neck cell (secretes mucus)
Parietal cell (secretes hydrochloric acid and intrinsic factor)
Chief cell (secretes pepsinogen and gastric lipase)
Surface mucous cell (secretes mucus)
(b) Sectional view of stomach mucosa showing gastric glands and cell types
Gastric pit
Submucosa
Surface mucous cells
Gastric pit
40x
Stomach mucosaSEM
Lumen of gastric gland
Gastric pitLamina propriaSurface mucous cell
Mucous neck cell
Parietal cell
Chief cells
Lumen of gastric gland
G cells
180xLM
(c) Fundic mucosa
Chyme in stomach lumen
Blood capillary in lamina propria
Basolateral membrane
Interstitial fluid
Alkaline tide
Parietal cellApical membrane
ATP ADP
H+
K+
Cl– H2O + CO2
CAH2CO3 H+ + HCO3
– HCO3– HCO3
–
Cl–
Key:
Proton pump(H+/K+ ATPase)
K+ (potassium ion) channel
Cl– (chloride ion) channel
Carbonic anhydrase
Diffusion
HCO3– /Cl– antiporter
HCO3–
Cl–
CA
Lumen of stomach
Parietal cell
Interstitial fluid
Acetylcholine (ACh)
ACh receptor
Gastrin
Gastrin receptor
Histamine
Histamine receptor
HCl secretion
Apical membrane
Basolateralmembrane
Uncinate process
Right lobe of liver
Left hepatic duct
Falciform ligament
Diaphragm
Right hepatic duct
Cystic duct
Gallbladder:
Neck
Body
Fundus
Duodenum
(a) Anterior view
Accessory duct (duct of Santorini)
Hepatopancreatic ampulla(ampulla of Vater)
Jejunum
Pancreatic duct (duct of Wirsung)
Common bile duct
Common hepatic duct
Round ligament
Pancreas
Coronary ligament
Left lobe of liver
Head
Body
Tail
Major duodenal papilla
Mucosa of duodenum
Common bile ductPancreatic duct (duct of Wirsung)
(b) Details of hepatopancreatic ampulla
Hepatopancreatic ampulla (ampulla of Vater)
Sphincter of the hepatopancreatic ampulla (sphincter of Oddi)
Common bile duct
Right hepatic duct
Common hepatic duct from liver
Cystic duct from gallbladder
Duodenum
SphincterLiver
Key:
Gallbladder
Pancreas
Left hepatic duct
(c) Ducts carrying bile from liver and gallbladder and pancreatic juice from pancreas to duodenum
Pancreatic duct from pancreas
(d) Anterior view
Falciform ligament
Diaphragm
Spleen
Tail of pancreas
Pancreatic duct (duct of Wirsung)
Body of pancreas
Head of pancreas
Liver
Hepatic bile duct
Cystic bile duct
Gallbladder
Common bile duct
Major duodenal papilla
Duodenum
Common bile duct
MEDIAL
SUPERIOR
(e) Anterior view
Uncinate process
Body of pancreas
Tail of pancreas
Head of pancreas
Majorduodenal papilla
Duodenum
LATERAL
Pancreatic duct (duct of Wirsung)
Hepatic sinusoids
Hepatic laminae
Bile duct
Connective tissue
Branch of hepatic portal vein
Central vein
(a) Overview of histological components of liver
Hepatocyte
Branch of hepatic artery
Inferior vena cava
Hepatic artery
Hepatic portal vein
Liver
Portal triad:
Hepatic sinusoid
To hepatic vein
Hepatic laminae
Branch of hepatic artery
Branch of hepatic portal vein
Bile canaliculi
Hepatocyte
Stellatereticuloendothelial(Kupffer) cell
Connective tissue
(b) Details of histological components of liver
Hepatic sinusoids
Bile duct
Central vein
Portal triad:
(c) Photomicrographs
100x
50x
150x
Hepatocyte
Central vein
Sinusoid
Portal triad:Branch of hepatic artery
Branch of hepatic portal vein
Bile duct
LM
LM
LM
Central vein
Hepatic lobule Portal lobule
Portal triad
(d) Comparison of three units of liver structure and function
Hepatic acinus
(e) Details of hepatic acinus
Central vein
Central vein
Portal triad
Zone 1
Zone 2
Zone 3
Oxygenated blood from hepatic artery
Right atrium of heart
Nutrient-rich, deoxygenated blood from hepatic portal vein
Inferior vena cava
Liver sinusoids
Hepatic vein
Central vein
2
3
4
5
6
1
DUODENUM
JEJUNUM
ILEUM
Stomach
Large intestine
(a) Anterior view of external anatomy
Circular folds (plicae circulares)
(b) Internal anatomy of jejunum
(a) Relationship of villi to circular folds
Submucosa
Villi
Circular layer of muscle
Longitudinal layer of muscle
Serosa
Circular folds
Circular folds (plicae circulares)
MUSCULARIS
Muscularis mucosae
Absorptive cell
Goblet cell
Lacteal
Lamina propria
Enteroendocrine cell
Paneth cell
Lymphatic nodule
Lymphatic vessel
Arteriole
Venule
Circular layer of muscle
Myenteric plexus
Longitudinal layer of muscle
(b) Three-dimensional view of layers of the small intestine showing villi
VilliBlood capillary
Lacteal Opening of intestinal gland
Lumen of small intestine
SUBMUCOSA
MUCOSA
SEROSA
Lacteal
Microvilli
Absorptive cell (absorbs nutrients)
Goblet cell (secretes mucus)
Enteroendocrine cell (secretes the hormones secretin, cholecystokinin, or GIP)
Paneth cell (secretes lysozyme and is capable of phagocytosis)
Blood capillary
Submucosa
Muscularis
Lymphatic vessel
Venule
Arteriol
Muscularis mucosae
Intestinal gland
Lamina propriaMucosa
(c) Enlarged villus showing lacteal, capillaries, intestinal glands, and cell type
(a) Wall of duodenum
Duodenal gland
Muscularis mucosae
Intestinal glands
Muscularis
Submucosa
Mucosa
Villi
Lumen of duodenum
45xLM
160xLM
(b) Several villi from duodenum
Duodenum
Intestinal glands
Lamina propria
Absorptive cell
Goblet cell
Simple columnar epithelium
Lumen of duodenum
Brush border
Villi
14xLM
Muscularis
(c) Lymphatic nodules in ileum
Lumen of ileum
Villus
Solitary lymphatic nodule
Submucosa
Brush border
46,800xTEM
(d) Several microvilli from duodenum
Simple columnar epithelial cell
Microvilli
Epithelial cells of villus
(a) Mechanisms for movement of nutrients through absorptive epithelial cells of villi
Glucose and galactose
Secondary active transport with Na+
Fructose Facilitated diffusion
Amino acids Active transport or secondary active transport with Na+
Dipeptides
TripeptidesSecondary active transport with H+
Small short-chain fatty acids
Simple diffusion
Monoglycerides
Large short-chain and long-chain fatty acids Simple
diffusion
Facilitated
diffusion
Triglyceride
Chylomicron
To blood capillary of a villus
To lacteal of a villus
Diffusion
Basolateral surface
Monosaccharides
Diffusion
Amino acids
Micelle
Lumen of small intestine
Microvilli (brush border) on apical surface
(b) Movement of absorbed nutrients into blood and lymph
Left subclavian vein
HeartSmall short-chain fatty acid
Villus (greatly enlarged)
Chylomicron
Blood capillary
Lacteal
Arteriole
Amino acid
Monosaccharide
Venule
Blood
LymphLymphatic vessel
Hepatic portal vein
Thoracic duct
Liver
Total absorbed = 9.2 liters
ABSORBED
Ingestion of liquids(2.3 liters)
Saliva (1 liter)
Gastric juice(2 liters)
Bile (1 liter)
Pancreatic juice(2 liters)
Intestinal juice (1 liter)
Total ingested and secreted= 9.3 liters
INGESTED AND SECRETED
Small intestine (8.3 liters)
Large intestine (0.9 liters)
Excreted in feces (0.1 liter)
Fluid balance in GI tract
RECTUM
Right colic (hepatic) flexure
ASCENDING COLON
Teniae coli
CECUM
Ileocecal sphincter (valve)
VERMIFORM APPENDIX
(a) Anterior view of large intestine showing major regions
IleumMesoappendix
TRANSVERSE COLON
Left colic (splenic) flexure
DESCENDING COLON
Teniae coli
SIGMOID COLON
Haustra
Omental appendices
ANAL CANAL
ANUS
Internal anal sphincter (involuntary)
Rectum
Anal canal
(b) Frontal section of anal canal
Anal columnAnus
External anal sphincter (voluntary)
(a) Three-dimensional view of layers of large intestine
Muscularis mucosae
Lymphatic vessel
Arteriole
Venule
Circular layer of muscle
Myenteric plexus
Longitudinal layer of muscle
Absorptive cell
Goblet cell
Intestinal gland
Lamina propria
Openings of intestinal glands
Lymphatic nodule
Lumen of large intestine
SUBMUCOSA
MUCOSA
MUSCULARIS
SEROSA
(b) Sectional view of intestinal glands and cell types
Openings of intestinal glands
Intestinal gland
Muscularis mucosae
Submucosa
Absorptive cell (absorbs water)
Lymphatic nodule
Goblet cell (secretes mucus)
Lamina propria
Microvilli
(c) Portion of wall of large intestine
Lumen of large intestine
Intestinal gland
Lamina propria
Muscularis mucosae
Lymphatic nodule
Mucosa
Submucosa
Muscularis
Serosa315xLM
300xLM
Lumen of large intestine
(d) Details of mucosa of large intestine
Opening of intestinal gland
Lamina propria
Intestinal gland
Goblet cell
Absorptive cell
Increase in acidity of stomach chyme; mixing of stomach contents; emptying of stomach
Food entering stomach disrupts homeostasis by
pH of gastric juice Distention (stretching) of stomach walls
Control center
Input
Output
Nerve impulses
Nerve impulses (parasympathetic)
Effectors
Submucosal plexus
Parietal cells secrete HCI and smooth muscle in stomach wall contracts more vigorously
HCI
Return to homeostasis when response brings pH of gastric juice and distention of stomach walls back to normal (pre-eating status)
Receptors
Chemoreceptors and stretch receptors in stomach detect pH increase and distention
Chemoreceptors and stretch receptors in stomach detect pH increase and distention
Increasing