Digestive system I Flashcards
What are the 4 main layers of the GI tract?
Tunica mucosa
Tunica submucosa
Tunica muscularis
Tunica serosa
Describe the Tunica Mucosa
Innermost layer
What are the 3 layers of the Tunica mucosa?
Epithelial lining
Lamina propria
Muscularis mucosae
Describe the Tunica submucosa
Contains glands & lymphatic tissue, blood vessels, irregular connective tissue, Miesser nerve plexus
Describe the Tunica muscularis
2 or more layers of smooth muscle (circular & longitudinal)
Does the Tunica muscularis have nerves?
Yes, myenteric plexus located in the connective tissue between the 2 muscle layers
What 2 plexuses form the ENS?
Myenteric & Miessners
Describe the Tunica Serosa
Mesothelium
Made of simple squamous epithelium
When is Tunica serosa used vs Tunica adventitia?
Serosa: intraperitoneal organs
Adventitia: retroperitoneal organs
What are the 3 surfaces of the lips?
Skin
Oral mucosa
Muco-cutaneous junction
What is the difference between oral mucosa in pigs and ruminants?
Ruminants have keratinized oral mucosa
What type of muscle is present in the core of the lips?
Skeletal muscle
WHat is the hard palate? What is the epithelium covering it?
Bony roof of the mouth
Covered by keratinized stratified squamous epithelium
What are dental pads?
Heavily keratinized hard palates in ruminants
What is the soft palate?
Separates oral cavity from nasopharynx
How are tongue muscle fibers oriented?
In all directions
What is the lyssa of the tongue?
Cord-like structure that extends on ventral mid-line
What are the 4 types of tongue papillae?
Filiform
Fungiform
Vallate
Foliate
Which tongue papillae does not have gustatory receptors?
Filiform
Which tongue papillae are most heavily keratinized?
Filiform
What are Ebner’s glands?
Gustatory glands located in the sulcus of foliate papillae
Which is the largest tongue papillae?
Vallate
What is the vallate papillae surrounded by?
Deep furrow
Where are taste buds located on the vallate papillae?
Lateral side opening in to sulcus
What are the 3 cell types associated with taste buds?
Sustentacular cells
Gustatory cells
Basal cells
What is the purpose of sustentacular cells?
Support
What is the purpose of basal cells?
Stem cells
What are “taste hairs”?
Microvilli that extend in to taste pore
What flavor do sodium ions create? Hydrogen ions? Sugars? Alkaloids? Amino acids?
Salty Sour Sweet Bitter Umami
Which types of animals have bracydont teeth? Hypsodont?
Carnivores
Herbivores
Do brachydont teeth continue growing after eruption?
No
WHat are the areas of the brachydont? DO hypsodont teeth have these areas?
Crown
Neck
Root
No
What is the hardest component of the human body?
Enamel (96% hydroxyapatite)
What cells secrete enamel?
Ameloblasts
Does enamel contain collagen?
No
What secretes dentin? Is collagen present in dentin?
Odontoblasts
Yes
What secretes cementum? Does it contain collagen?
Cementoblasts
Yes
WHat leads to periodontal disease?
build up of tartar
Describe steps of tooth development
thickening of mesenchyme bud cap bell erupted tooth
What is the dental lamina?
Stage I development: oral epithelium invades mesenchyme
What is the tooth bud?
Stage II development: dental lamina forms epithelial bulge
What is the enamel organ?
Stage III development: tooth bud increases in size and forms cap
What is the bell?
Stage IV development: cap is converted to bell by epithelium and papillary mesenchyme growth
Everything that forms the tooth comes from the mesenchyme except what?
Enamel comes from enamel organ
