General Layers Of Gi Tract Flashcards
Name the parts of the digestive system. Know the structure of the tongue, teeth, hard palate, soft palate and lips. Know the location and structural differences of the major salivary glands. Know the overall development of the teeth. Know the structure and innervations of the taste buds. Compare the digestive tract organs in terms of the four layers comprising their walls and relate any structural variations to differences in organ function. Know the characteristic structures i
What epithelium makes up the hard palate?
Parakeratinized and keratinized strafied squamous epithelium
Define parakeratinized epithelium.
No distinct stratum granulosum. The cells of the stratum corneum are keratinized and have nuclei.
The soft palate and internal surface of lips/cheeks have why type of epithelium?
nen-keratinized strafied squamous
Where is specialized mucosa located?
Lines the anterior 2/3 of dorsal tongue where the lingual papillae are located. Other areas of the dorsal tongue are keratinized stratified squamous.
Which type of taste buds are Von Ebner’s glands associated with? What type of secretion?
Pure serous secretion into the moat of circumvalate papillae
True or False: Filiform papillae can detect taste.
False. They dont have any taste buds.
What type of epithelium is found in filiform papillae?
heavily keratinized stratified squamous
What type of epithelium is found in fungiform papillae?
Non-keratinized or lightly keratinized stratified squamous
True ofFalse: Fungiform papillae can detect taste.
True.They do have taste buds.
What type of epithelium is found in circumvalate papillae?
Non-keratinized epithelium
Which glands are associated with circumvalate papillae?
Von Ebner’s glands
True or False: circumvalate papillae can detect taste.
True. They have about 250 taste buds/papillae
What is the function of foliate papillae?
rudementary in humans
What is Geographic tongue/ benign migratory glossitis?
Filiform papillae are involved
What is hairy tongue?
lengthining of papillae when stained with food make tongue look black and hairy
What are the four types of cells found in taste buds?
Taste receptor cells, dark cells, light cells, and basal cells.
What are the 5 major components of saliva?
- Mucin 2. Amylase 3. Lysozyme
4. sIgA 5. salivary proteins
Where are minor salivary glands located?
Lamina propria of oral cavity
What is a mucocele?
rupture of duct and spilling of saliva
What is a Ranula?
It is a mucocele in the floor of the mouth
Describe the duct system of the major salivary glands.
Intercalated ducts —> striated ducts—
–>Interlobular/excretory ducts (these are the ducts that leave the gland and open intothe oral caviy)
What type of epithelium is found in the intercalated ducts of major salivary glands?
Low cuboidal cells
What type of epithelium makes up the striated ducts?
Simple cuboidal
What type of epithelium is makes up the interlobular/excretory ducts?
simple cuboidal—simple columnar —stratified cuboidal—stratified columnar —stratified squamous
What type of secretions come from the parotid gland?
Purely serous
What type of secretions come from the submandibular gland?
Mixed but predominantly serous
What type of secretion come from the sublingual gland?
Mixed but predominantly mucus
Which gland/s has/have serous demilumes?
Submandibular and sublingual glands
What produces Enamel?
Ameloblasts
What produces Dentin?
Odontoblasts
What produces Cementum?
Cemenoblasts
Which part of the tooth is affected by Scurvy?
Peridontal ligamen
What week does tooth development begin?
6th week
What part of the tooth is derived from neural crest cells?
Everything but the enamel
What part of the tooth is derived from ectoderm?
Enamel
What are the general layers of the digestive tract?
- Mucosa (epithelium, lamina propria, Muscularis mucosae) 2. Submucosa 3. Muscularis externa 4. Serosa/adventitia
Where is the meissner’s plexus located?
In the submucosa. The plexus is also called the submucosal plexus.
What layers of muscle are found in the muscularis externa layer of the digestive tract?
Inner circular muscle and outer longitudinal muscle
In what layer of the GI tract are lymphoid nodules mucous glands present?
Submucosa layer
What type of connective tissue is found in the submucosa?
dense CT
Which layer of the GI tract is responsible for peristalsis?
Muscularis externa
Where is the myenteric plexus (a.k.a. Auerbach’s plexus) located?
Between inner circular and outer longitudinal muscles of the muscularis externa.
What type of glands are found in the submucosa of the esophagus and what do they secrete?
Esophageal glands; mucus
True or False: Cardiac glands are found in the submucosa of the proximal esophagus.
FALSE. Cardiac glands may be present in the LAMINA PROPRIA of the DISTAL esophagus.
True or False.. Langerhans cells are present in the epithelium of the esophagus.
TRUE
What type of epithelium is present in the esophagus?
non-keratinized strafied squamous epithelium
What is Barrett’s esophagus?
Metaplasia: stratified squamous epithelium is replaced by simple columnar epithelium. Presentation is chronic heartburn.
Congenital vs. Acquired Barrett’s esophagus
Acquired is pre-cancerous. Chronic heartburn should not be ignored.
Surface mucous cells are present in what part of the digestive tract?
Stomach epithelium
True or False. Cardia glands have APUD cells
True
True or False: Cardia glands do not have stem cells.
FALSE: They do have stem cells.
What is the pit/gland ratio in cardiac glands?
1/2 : 1/2
What is the pit/gland ratio in pyloric glands?
2/3 : 1/3 (the glands are shorter than the pits)
What type of cells are found in the short glands of the pylorus?
- Muscus secreting cells 2. EEC cells 3. G cells 4. D cells
What is produced by G cells?
G cells produce gastrin which stimulates HCl secretion.
What is produced by D cells?
D cells produce somatostatin which inhibits gastrin secretion.
True or False: Somatostatin stimulates gastrin secretion which in turn inhibits HCl secretion.
FALSE: Somatostatin inhibits gastrin when then decreases HCl production
What is the pit/gland ratio of Gastric glands?
1/5 : 4/5 (shalow pits and deep glands)
What type of cells are found in the neck of fundic glands?
- Mucus neck cells 2. Parietal cells
3. stem cells
Where are gastric glands found?
Fundus and body
Where are stem cells found in the stomach?
Neck of gastric glands
What types of cells are found in the base of gastric glands?
Chief cells, EEC
What is the function of Chief cells?
pepsinogen
What is the function of parietal cells?
Produce HCl and Intrinsic factor
What is the function of intrinsic factor?
Binds to Vit B12 in the Ileum
What are the muscular layers of the stomach?
It is unique in that it has three layers.
1. Inner oblique 2. Middle circular 3. Outer longitudinal
