Digestive System (Final Exam) Flashcards
What is the lining epithelium of the GI tract?
Stratified squamous epithelium from lips to nonglandular stomach.
Simple columnar in glandular stomach and intestine.
What is the oral cavity? What is it composed of? What do ruminants have that is special here?
Lips, cheeks, palate, pharynx, tongue.
Lamina propria of CT (submucosa missing)
Has labiae and buccal salivary glands and tonsils.
Dental pad in ruminants (keratinized)
Describe the tongue.
Covered by mucosa (lamina propria = loose CT, gland); Submucosa is missing!
Dorsal/upper side is keratinized and surface is irregular due to present of papillae (mechanical and gustatory)
Some papillae have taste buds
Skeletal muscle arranged in 3 DIRECTION - move tongue in all directions
What are the cells that form the hard structures of the tooth?
Ameloblasts –> Enamel (covers external surface)
Odontoblasts –> Dentin (beneath enamel)
Cementoblasts –> Cementum
What are the soft tissues of the tooth?
Tooth pulp - loose CT and nerves (root mesenchyme is derived from neural crest cells)
Periodontal Ligament - from fibroblasts
Describe tooth development.
Odontoblasts cover surface of mesenchymal papilla and produce predentin and dentin
Ameloblasts are tall columnar cells that will produce enamel
What is the general organization of digestive organs?
Mucosa - inner epithelium, middle lamina propria (loose CT of mucous membrane with cells of immune system), this outer muscularis mucosae (smooth muscle of mucosa)
Submucosa (+/-) - not in tongue
Muscularis - inner circular, outer longitudinal
Tunia Serosa (mesothelial lining) or Adventitia (no mesothelium) - peritoneum, pleural lining
Describe the Tunica Submucosa
Loose CT, loose than lamina propria mucosae
Facilitates motility of mucosa
May contain glands, vessels, nerve plexus (submucous plexus of Meissner) and lymphatic nodules
Describe the Tunica Muscularis
Smooth or skeletal muscle
Usually 2 layers: inner circular, outer longitudinal
Control lumen size, motility of tube
Contains myenteric plexus (Auberbach), vessels, nerves, nerve cell bodies in ganglia or on plexus
Describe Tunica Serosa/Adventita
T. Serosa = mesothelium, loose CT +/- adipose tissue
T. Adventitia - loose/dense CT only, no mesothelium
Most external tunic.
If associated with pleural, pericardial or peritoneal cavities is composed of mesothelium and underlying CT
Where does Tunica Adventitia occur in the GI tract?
portion of esophagus, rectum
Also vagina, bronchi, trachea
Where passing through mediastinum, body wall or the neck.
Describe the esophagus.
Mucous glands in submucosa.
May have lamina muscularis mucosae
Heals poorly
Tunica muscularis may be skeletal or combo of skeletal/smooth
Tunica adventita is outermost in cervical and thoracic regions.
What are gastric pits?
Invaginations of lining epithelium
What type of glands is the cardiac region composed of? The fundic region?
Cardiac Region - mostly of mucous glands
Fundic Region - proper gastric glands (parietal and chief cells)
What are the 3 types of gastric glands?
- Mucous Glands
- Proper gastric glands
- Pyloric Glands
Describe the cardiac gland region of the stomach.
Near the esophageal stomach junction composed mainly of mucous glands and a few parietal cells
Describe the fundic region of the stomach
Composed of parietal (secrete hydrochloric acid, acidophilic, secrete intrinsic factor for vitamin B12 absorption) and chief cells/peptic cells (produce pepsinogen, basophilic, secrete chymosin (rennin in ruminants) in infants - curdles milk)