Figure 23.1 Alimentary canal and related accessory digestive organs.

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Figure 23.1 Alimentary canal and related accessory digestive organs.

Mouth (oral cavity)Tongue

Esophagus

LiverGallbladder

Anus

DuodenumJejunumIleum

Small intestine

Parotid glandSublingual glandSubmandibulargland

Salivaryglands

Pharynx

StomachPancreas(Spleen)

Transverse colonDescending colonAscending colonCecumSigmoid colonRectumAppendixAnal canal

Largeintestine

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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

Submucosa

LumenMucosa-associatedlymphoid tissue

Duct of gland outsidemucosa

Gland in mucosa

NerveArteryVein

Lymphaticvessel Mesentery

Mucosa• Epithelium• Lamina propria• Muscularis mucosae

Muscularis externa

• Longitudinal muscle • Circular muscleSerosa• Epithelium• Connective tissue

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Figure 23.7b Anatomy of the oral cavity (mouth).

UvulaPalatine tonsil

Sublingual foldwith openings ofsublingual ducts

Tongue

Gingivae (gums)

Hard palate

Soft palate

Opening ofsubmandibular duct

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Figure 23.9a The salivary glands.

Teeth

Ducts ofsublingualgland

Sublingualgland

Submandibularduct

Parotid duct

Body of mandible (cut)

Parotidgland

Tongue

Submandibulargland

(a)

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Figure 14.6 Swallowing.

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Figure 14.3 Motility of the gastrointestinal tract.

Esophagus• Mucosal epithelium is stratified squamous

Stomach

• Mucosal epithelium is simple columnar

• Liq uified food in the intestinal tract, first produced in the stomach is chyme.

• Contents of the intestinal tract in the fetus is meconium.

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Figure 23.14a Anatomy of the stomach.

Esophagus

Pyloric sphincter(valve) at pylorus

Rugae ofmucosa

Body

Lumen

Serosa

Lessercurvature

Greatercurvature

Muscularisexterna • Longitudinal layer • Circular layer • Oblique layer

(a)

Duodenum

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Figure 23.16 Photographs of a gastric ulcer lesion and of the bacteria that most commonly cause it.

Bacteria

Mucosalayer ofstomach

(a) A gastric ulcer lesion (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

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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.

1 4

5 7

2

8

6

3

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Figure 23.21 The duodenum of the small intestine, and related organs.

Jejunum

DuodenumHepatopancreaticampulla and sphincter

Gallbladder

hepatic ducts of liver

Bile duct

Main pancreatic duct

Pancreas

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

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Figure 23.26a Structure of the enzyme-producing tissue of the pancreas.

Smallduct

Acinar cells

Basementmembrane

Zymogengranules

Roughendoplasmicreticulum

(a)

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

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Figure 14.11 The hepatic portal system.

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Figure 23.25a-b Microscopic anatomy of the liver.

(a) (b)Lobule Central vein Connectivetissue 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

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Figure 23.25c Microscopic anatomy of the liver.

(c)

Interlobular veins(to hepatic vein) Central vein

Sinusoids

Portal triad

Plates ofhepatocytes

Portal vein

Bile duct (receivesbile from bile canaliculi)

Bile duct

ArteriolePortal venuleHepatic

macrophagesin sinusoid walls

Bile canaliculi

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Figure 14.19 Gallstones

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

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Figure 23.30d Mesenteries of the abdominal digestive organs.

(d)

Pancreas

LiverLesser omentum

Stomach

Duodenum

Greater omentumMesentery

Jejunum

Visceral peritoneum

Urinary bladder

Transverse colon

Ileum

Parietal peritoneum

Rectum

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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

Lesser omentumGallbladder

StomachDuodenum

Transverse colon

Small intestine

Cecum

(b)

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Figure 23.30c Mesenteries of the abdominal digestive organs.

Transverse colon

Descending colonJejunumMesentery

Sigmoid colon

Ileum

(c)

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Tooth Structure

Figure 22.11

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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)

IncisorsCentral (6–8 mo)

IncisorsCentral (7 yr)

Canine (eyetooth)(16–20 mo)

Canine (eyetooth)(11 yr)

Premolars(bicuspids)

First premolar(11 yr)

MolarsFirst molar(10–15 mo)

MolarsFirst molar (6–7 yr)

Lateral (8–10 mo) Lateral (8 yr)

Second molar(about 2 yr)

Second molar(12–13 yr)Third molar(wisdom tooth)(17–25 yr)(a)

Permanentteeth

Deciduous(milk) teeth Second premolar

(12–13 yr)