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Figure 23.1 Alimentary canal and related accessory digestive organs.
Mouth (oral cavity)
Tongue
Esophagus
Liver
Gallbladder
Duodenum
Jejunum
Small
intestine Ileum
Anus
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Parotid gland
Sublingual gland Salivary
Submandibular
glands
gland
Pharynx
Stomach
Pancreas
(Spleen)
Transverse colon
Descending colon
Ascending colon
Cecum
Sigmoid colon
Rectum
Appendix
Anal canal
Large
intestine
Figure 23.1 Alimentary canal and related accessory digestive organs.
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Figure 14.1 Organs and accessory organs of the digestive system and their functions.
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Figure 23.6 Basic structure of the alimentary canal.
Glands in submucosa
Mucosa
• Epithelium
• Lamina propria
• Muscularis
mucosae
Submucosa
Muscularis
externa
Nerve
Artery
Vein
Mesentery
Gland in mucosa
Lymphatic
Duct of gland outside
vessel
mucosa
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• Longitudinal
muscle
• Circular muscle
Serosa
• Epithelium
• Connective
tissue
Lumen
Mucosa-associated
lymphoid tissue
Figure 23.7b Anatomy of the oral cavity (mouth).
Gingivae (gums)
Hard palate
Soft palate
Uvula
Palatine tonsil
Tongue
Sublingual fold
with openings of
sublingual ducts
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Opening of
submandibular duct
Figure 23.9a The salivary glands.
Ducts of
sublingual
gland
Tongue
Teeth
Parotid
gland
Parotid duct
Sublingual
gland
(a)
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Body of
mandible (cut)
Submandibular
duct
Submandibular
gland
Figure 14.6 Swallowing.
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Figure 14.3 Motility of the gastrointestinal tract.
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Esophagus
• Mucosal epithelium is stratified squamous
Stomach
• Mucosal epithelium is simple columnar
• Liquified food in the intestinal tract, first
produced in the stomach is chyme.
• Contents of the intestinal tract in the fetus
is meconium.
Figure 23.14a Anatomy of the stomach.
Esophagus
Muscularis
externa
• Longitudinal layer
• Circular layer
• Oblique layer
Lesser
curvature
Serosa
Body
Lumen
Rugae of
mucosa
Greater
curvature
Duodenum
(a)
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Pyloric sphincter
(valve) at pylorus
Figure 23.16 Photographs of a gastric ulcer lesion and of the bacteria that most commonly cause it.
Bacteria
Mucosa
layer of
stomach
(a) A gastric ulcer lesion
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(b) H. pylori bacteria
Microscopic Anatomy of the Stomach
Figure 22.15
Small Intestine
• Three subdivisions: duodenum, jejunum,
and ileum
• The bile duct and main pancreatic duct
join the duodenum at the hepatopancreatic
ampulla
Figure 14.9e The wall of the small intestine.
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Figure 14.9c–d The wall of the small intestine.
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Figure 14.10 Locations and digestive functions of the liver, gallbladder, and pancreas.
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Figure 14.10 Locations and digestive functions of the liver, gallbladder, and pancreas.
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1
2
6
5
7
3
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Figure 23.21 The duodenum of the small intestine, and related organs.
hepatic ducts
of liver
Bile duct
Pancreas
Jejunum
Gallbladder
Main pancreatic duct
Hepatopancreatic
ampulla and sphincter
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Duodenum
Pancreas
• Exocrine function
– Secretes pancreatic juice which contains
enzymes which break down all categories of
foods
– Secretes HCO3– which neutralizes acidic
chyme, and provides optimal environment for
pancreatic enzymes
• Enzymes are released in inactive form and
activated in the duodenum
Figure 23.26a Structure of the enzyme-producing tissue of the pancreas.
Small
duct
Acinar cells
Basement
membrane
Zymogen
granules
Rough
endoplasmic
reticulum
(a)
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Liver
• The largest gland in the body
• Has four lobes
• Hepatic artery- brings oxygen rich blood to
the liver
• Hepatic portal vein- brings nutrient rich
blood from the digestive organs to the liver
• Both of these empty into the sinusoids of
the liver
Figure 14.11 The hepatic portal system.
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Figure 23.25a-b Microscopic anatomy of the liver.
(a)
Lobule
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(b)
Central vein
Connective
tissue septum
Liver: Microscopic Anatomy
• Liver sinusoids – enlarged, leaky capillaries
• Kupffer cells – hepatic macrophages found in liver
sinusoids
• Hepatocytes’ functions include:
–
–
–
–
–
–
Production of bile
Processing bloodborne nutrients
Storage of fat-soluble vitamins
Detoxification
Protein synthesis
Synthesis of cholesterol
• Secreted bile flows between hepatocytes toward
the bile ducts
Figure 23.25c Microscopic anatomy of the liver.
Interlobular veins
(to hepatic vein)
Central vein
Sinusoids
Bile canaliculi
Plates of
hepatocytes
Bile duct (receives
bile from bile
canaliculi)
Hepatic
macrophages
in sinusoid walls
Portal vein
(c)
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Bile duct
Portal venule
Arteriole
Portal triad
Figure 14.19 Gallstones
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Large Intestine
• Subdivided into the cecum, appendix, colon,
rectum, and anal canal
– Cecum and appendix have digestive function in
herbivores
• Has three bands of longitudinal smooth
muscle in its muscularis
Figure 23.30d Mesenteries of the abdominal digestive organs.
Liver
Lesser omentum
Pancreas
Stomach
Duodenum
Transverse colon
Mesentery
Greater omentum
Jejunum
Ileum
Visceral peritoneum
Parietal peritoneum
(d)
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Urinary bladder
Rectum
Figure 23.30a Mesenteries of the abdominal digestive organs.
Liver
Gallbladder
Spleen
Stomach
Greater omentum
Small intestine
Cecum
(a)
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Figure 23.30b Mesenteries of the abdominal digestive organs.
Liver
Gallbladder
Lesser omentum
Stomach
Duodenum
Transverse colon
Small intestine
Cecum
(b)
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Figure 23.30c Mesenteries of the abdominal digestive organs.
Transverse colon
Descending colon
Jejunum
Mesentery
Sigmoid colon
Ileum
(c)
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Tooth Structure
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Figure 22.11
Tooth Structure 1
• Two main regions – crown and the root
• Crown – exposed part of the tooth above the
gingiva (gum)
– Covered with enamal, the hardest substance in the
body, which is composed of calcium and phosphate
salts
• Root – portion of the tooth embedded in the
jawbone
– Covered with cementum, which is also calcified
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Tooth Structure 2
• Periodontal ligament
– Anchors the tooth in the jaw
• Dentin – bonelike material beneath the enamel cap
that forms the bulk of the tooth
• Pulp cavity –center of tooth, containing connective
tissue, blood vessels, and nerves
• Root canal – extension of the pulp cavity out of the
root
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• Teeth are classified according to their
shape and function
– Incisors: chisel-shaped teeth adapted for
cutting or nipping
– Canines: conical or fanglike teeth that
tear or pierce
– Premolars (bicuspids) & molars
(tricuspids): have broad crowns with
rounded tips and are best suited for
grinding or crushing
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Figure 23.10a Human dentition.
(DON’T NEED TO KNOW AGE OF APPEARRANCE OF TEETH)
Incisors
Central (6–8 mo)
Lateral (8–10 mo)
Canine (eyetooth)
(16–20 mo)
Molars
First molar
(10–15 mo)
Second molar
(about 2 yr)
(a)
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Deciduous
(milk) teeth
Incisors
Central (7 yr)
Lateral (8 yr)
Canine (eyetooth)
(11 yr)
Premolars
(bicuspids)
First premolar
(11 yr)
Second premolar
(12–13 yr)
Molars
First molar (6–7 yr)
Second molar
(12–13 yr)
Third molar
(wisdom tooth)
(17–25 yr)
Permanent
teeth