Tissue Layers (Tunics) of the Alimentary Canal Organs Page 466

Tissue layers of the Alimentary Canal Organs Four layers from deep to superficial: 1. Mucosa 2. Submucosa 3. Muscularis Externa 4. Serosa

Figure 14.3 Basic structure of the alimentary canal wall. Visceral peritoneum Submucosal glands Mucosa Surface epithelium Lamina propria Muscle layer Submucosa Muscularis externa Longitudinal muscle layer Circular muscle layer Serosa (visceral peritoneum) Nerve Gland Lumen Artery Vein Duct of gland

Tissue layers of the Alimentary Canal Organs Mucosa Surface epithelium Connective tissue Smooth muscle Submucosa soft connective tissue vascularization nerves lymphoid tissue (MALT) lymph vessels © 2015 Pearson Education, Inc.

Tissue layers of the Alimentary Canal Organs Muscularis externa smooth muscle layers Outer longitudinal layer Inner circular layer Serosa Visceral peritoneum —innermost Parietal peritoneum —outermost layer lines the abdominopelvic cavity by way of the mesentery (a large membrane extension) The mesentery holds organs in place, stores fat, and provides a route for vessels and nerves © 2015 Pearson Education, Inc.

Figure 14.3 Basic structure of the alimentary canal wall. Visceral peritoneum Intrinsic nerve plexuses Myenteric nerve plexus Submucosal nerve plexus Submucosal glands Mucosa Surface epithelium Lamina propria Muscle layer Submucosa Muscularis externa Longitudinal muscle layer Circular muscle layer Serosa (visceral peritoneum) Nerve Gland in mucosa Lumen Artery Mesentery Vein Duct of gland outside alimentary canal Lymphoid tissue

Figure 14.5 Peritoneal attachments of the abdominal organs. Diaphragm Falciform ligament Lesser omentum Liver Spleen Pancreas Gallbladder Stomach Duodenum Visceral peritoneum Transverse colon Greater omentum Mesenteries Parietal peritoneum Small intestine Peritoneal cavity Uterus Large intestine Cecum Rectum Anus Urinary bladder (a) (b)