Digestive Tract Flashcards
What type of epithelium lines the lips and cheeks? For the tongue?
Lips/Cheek: Oral mucosa = oral epithelium = non-keratinized stratified squamous epithelium
Tongue: Non-keratinized stratified squamous (mostly)
What type of epithelium lines the nasal mucosa?
This is respiratory epithelium = pseudostratified ciliated columnar epithelium with goblet cells
What are the 3 cell types that create the calcified tissue of teeth? What does each cell type make?
- Ameloblasts - make enamel matrix
- Odontoblasts - make dentin matrix
- Cementoblasts - make cementum matrix
What is papillae? What are the types of papillae?
Papillae are little ridges on the tongue that are associated with sensory and specialized nerves on dorsal surface.
- Filiform - sensory nerves at base; general sensation (tactile)
- Fungiform - taste buds
- Vallate (cucumvallate) - taste buds; valleys and moats surround them and allow salive to pool in the region and expose taste buds to contents of oral cavity
What is the sulcus terminalis?
Apex comes from foramen cecum (embryological remnant). Anterior 2/3 and posterior 1/3 of tongue develop differently, and this is the site where they come together.
What is a taste bud?
Specialized cells int he epithelial layer that help process and send signals to bran to process sensation of taste.
What is a taste pore?
Food matter settles here so it can interact with receptor on surface and eventually stimulate a neuron that give us a taste sensation
How do taste receptor cells get replaced?
Basal cells –> Sustentacular cells –> taste receptor cells
What are the layers in the wall of the digestive tract?
Inside –> Out:
- Lumen
- Mucosa - epithelium, lamina propria, muscularis mucosae (involuntary smooth muscle)
- Submucosa
- Muscularis externa - 2 layers of smooth muscle (stomach = 3) –>inner circular and outer longitudinal
- Serosa or Adventitia
What is the difference between the serosa and adventitia? How does this affect differences in pain?
They are both layers of connective tissue, but only the serosa has simple squamous epithelium on the outside. Pain is dull if nerves are innervating the serosa layer. Pain in adventitia is sharp and localized.
What are the 2 enteric or myenteric plexuses of which the post-ganglionic parasympathetic neurons are located?
- Meissner’s plexus - submucosa - vagus n.
2. Auerbach’s plexus - muscularis externa
What is in the submucosa layer of the esophagus?
Mucous glands. They secrete mucus to line epithelium surface to protect it from acid reflux of stomach
What change occurs within the muscularis externa of the esophagus?
The muscle transitions from skeletal muscle to smooth muscle. It is mostly smooth muscle, however.
What is Barret’s disease?
Condition that occurs du to prolonged exposure to acid reflux. The esophagus can proliferate in order to repair itself, but the stomach can also help. The stomach has a faster proliferation rate, so it changes the lining from stratified squamous to simple columnar. This is not as protective for the esophagus and so the blood vessels and connective tissue get hurt. The layer can erode –> esophageal cancer.
What type of gland is the stomach? What do they each secrete?
The stomach is an exocrine gland, that drains into lumen. It is also an endocrine gland that secretes substances into circulation that signal digestive tract that food is on the way or the CNS that we need food.
