GI 1 Flashcards
Digestive System Composition
alimentary canal, tongue, teeth, salivary glands, pancreas, and liver.
Define Alimentary Canal
Hollow tube of varying diameter beginning at the oral cavity including esophagus, stomach, small and large intestine.
Name the 4 layers of the alimentary canal
Mucosa, Submucosa, Muscularis Externa, mesothelium (either serosa or adventitia)
Mucosa of alimentary canal
faces the lumen. Contains lining epithelium, lamina propria (loose CT), and muscularis mucosa
Submucosa of alimentary canal
dense CT. vascular plexus to mucosa. Nerve plexus called submucosal plexus or Meissner’s plexus.
Muscularis Externa of alimentary canal
mostly smooth muscle. Upper esophagus is skeletal muscle and middle esophagus is mixed muscle types. Organized into 2 layers with a nerve plexus in the middle.
Inner Circular layer
part of the muscularis externa circling the espophagus
Outer longitudinal layer
part of the muscularis running along the espophagus
Auerbach’s Plexus
aka myenteric plexus. Nerve layer of muscularis externa that lies between the inner circular and outer longitudinal layers
Serosa
thin layer of CT underlying mesothelium wihtin the peritoneal cavity.
Adventitia
Portion of the alimentary canal not within the peritoneal cavity is covered with this portion of mesothelium. It lacks simple squamous epithelium and has loose CT that blends into surrounding structures
Mesothelium
Simple squamous epithelium covering the alimentary canal within the peritoneal canal
Oral Cavity
differs from alimentary canal proper due to lack of muscularis externa or serous/advetnitia.
Oral Mucosa
non-keratinzed stratified squamous epithelium with the exception of adult hard palate, gingiva, and tongue keratinization.
Oral Submucosa
No clear distinction from lamina propria. Contains the minor salivary glands.
Minor Salivary Glands
mucous-secreting branched tubular or tubuloaveolar glands. They are intrinsic (within wall of oral cavity).
Tongue
muscular organ projecting into the oral cavity. Covered in SSE that is often keratinzed in adults. Contains both intrisic and extrinsic skeletal muscle fibers as well as 4 types of papillae.
Filiform papillae
most abundant type of lingual papillae. Small concical projections of highly keratinized epithelium and CT. NO TASTE BUDS just mechanical role. Cover whole anterior tongue with backwards projections/tips.
Fungiform Papillae
Mushroom shaped projections scattered amoung filiform papillae and more numerous at the tip of the tongue. Apical surface of these buds carry the taste buds.