Chapter 8: Gastrointestinal System
Please familiarize yourself with these keywords before you start reading the chapter:
- Autonomic ganglia (plexi)
- Organized clusters of neurons and nerve fibers that are part of the autonomic (sympathetic and parasympathetic) nervous system. In the gastrointestinal tract, there are two distinct ganglion layers that mediate peristalsis: submucosal (Meissner’s) plexus and myenteric (Auerbach’s) plexus.
- Brush border (microvilli)
- The histologically apparent thin microvillus layer of enterocytes.
- Chief cells
- Secretory epithelial cells of the stomach that produce pepsinogen.
- Crypts of Lieberkühn (intestinal crypts)
- Glands, located at the base of intestinal villi, in which reside the proliferative stem-like cells of the intestine.
- A hyalinized protein forming a thick, protective layer overlying the mucosa of the gizzard of birds.
- Lamina propria
- The fibrovascular supporting core underlying mucosal epithelium, often containing lymphatics, blood vessels, and resident immune cells. The lamina propria, along with the mucosal epithelium, is included in the layer “mucosa”.
- Margo plicatus
- The linear junction of the non-glandular (orad) and glandular (aborad) stomach of the horse.
- Muscularis mucosa
- A thin layer of smooth muscle present in the mucosa of the stomach, intestine, and bronchi that separates the mucosa from the underlying submucosa.
- Paneth cell
- Secretory intestinal pithelial cells located within intestinal crypts with eosinophilic, round cytoplasmic granules containing antimicrobial compounds.
- Parietal cells (Oxyntic cells)
- Secretory epithelial cells of the stomach that produce hydrochloric acid (HCl).
- Pars esophagea
- A well-delineated region of non-glandular (squamous) gastric mucosa within the proximal portion of the stomach in the pig, immediately distal (aborad) to the esophagus.
- Taste bud
- Structures, primarily located on the tongue, composed of chemoreceptor cells (gustatory, sustentacular, and basal cells) that sense and transmit the sensation of taste to the brain.