Digestive System I Flashcards
Associated glands of digestive system
- Salivary glands
- Liver
- Pancreas
4 parts of oral cavity
- Lips
- Palates
- Tongue
- Teeth
4 main layers of GI
- Tunica mucosa
- Tunica submucosa
- Tunica muscularis
- Tunica serosa
Tunica mucosa aka?
Mucosal membranes
Tunica mucosa
Innermost layer
3 sublayers of tunica mucosa
- Epithelial lining
- Lamina propria
- Muscularis mucosae
Cells of epithelial lining
Stratified +/- keratin
Lamina propria is made of?
Loose CT
Muscularis mucosae is made of?
Smooth muscle
Tunica submucase consists of?
- Dense irregular CT
- Blood vessels
- Lymph vessels
- Nerve plexus (Miessner)
Miessner
Nerve plexus located in tunica submucosa
Tunica submucosa may contain?
- Glands
2. Lymphatic tissue
Tunica muscularis aka?
Muscularis externa
Tunica muscularis contains?
Inner circular and outer longitudinal layers of smooth muscle
CT between inner circular and outer longitudinal smooth muscle layers of tunica muscularis contains?
- Blood vessels
- Lymph nodes
- Nerve plexus (myenteric)
Myenteric nerve plexus located?
Between inner circular and outer longitudinal layers of tunica muscularis
ENS stands for?
Enteric nervous system
What forms ENS?
- Miessner’s nerve plexus
2. Mysenteric nerve plexus
“Second brain” is the?
ENS
ENS has?
Autonomous function
ENS innervation
Some from ANS, but operates independently of brain and spinal cord
Tunica serosa
Thin layer of loose CT
Rich in blood vessels, lymph vessels and adipose tissue
Tunica serosa is covered by?
Mesothelium
Mesothelium cells
Simple squamous epithelium
Covering of intraperitoneal organs
Mesothelium
Covering of retroperitoneal organs
Tunica adventitia
Lips are?
Folds of fibroelastic and skeletal tissue at entrance to GI tract
3 surfaces of lips
- Skin
- Oral mucosa
- Muco-cutaneous junction
Lip skin cells
Stratified squamous +/- keratinization
Oral mucosa cells in pigs and carnivores
Non-keratinized
Oral mucosa cells in ruminants and horses
Keratinized
Core of lips has?
Skeletal muscle
Orbucluaris oris m.
Skeletal muscle in core of lips
2 types of palates
- Hard palate
2. Soft palate
What is hard palate?
Bony roof of mouth
Hard palate covered by?
Mucuosa (stratified squamous epithelium with keratin)
Hard palate texture
Ridged (rugae)
Dental pads
Thick keratin layer in hard palate of ruminants
Soft palate is?
Posterior fibrous and muscular extension of hard palate
Soft palate separates?
Oral cavity from nasopharynx
Tongue is?
Mass of striated muscle
Tongue fibers oriented?
All directions
Dorsal surface of tongue
Tonsils and papillae
Ventral surface of tongue
Typical mucosa
Lyssa is?
Cordlike structure extending along ventral midline of tongue
Lyssa is well developed in?
Carnivores
Lyssa consists of?
- Dense collagenous tissue
- Fat
- Skeletal m.
- Sometimes cartilage
4 types of tongue papillae
- Filiform
- Fungiform
- Vallate
- Foliate
Only non-gustatory papillae
Filiform
Filiform papillae
Fairly small, cover most of surface
Filiform papillae shape
Elongated conical
Filiform papillae keratinization
Heavily keratinized
Filiform papillae function
Provide friction to help move food
Fungiform papillae
Larger, less common (interspersed among filiform p.)
Fungiform papillae shape
Mushrom
Funigofrm papillae keratinization
Lightly keratinized
Taste buds on fungiform papillae
Few
Foliate papillae
Several parallel ridges on each side of tongue
Foliate papillae keratinization
Non-keratinized epithelium
Foliate papillae shape
Leaf-shaped
Taste buds on foliate papillae
Few
Glands of foliate papillae
Gustatory
Gustatory glands open into?
Sulcus of foliate and vallate papillae
Gustator glands aka?
Ebner’s glands
Foliate papillae are commonly seen in what animals?
- Rabbits
2. Hares
Vallate papillae aka?
Circumvallate p.
Largest papillae
Vallate papillae
How are vallate papillae arranged?
8-12 arranged in pairs
Vallate papillae shape
Round
Vallate papillae are surrounded by?
Deep furrow (moat)
Papillae with most taste buds?
Vallate papillae
Vallate papillae glands
Gustatory glands
Taste buds are?
Ovoid intraepithelial cell masses
Taste buds extend from ? and open through?
Basement membrane → open through taste pore at surface
3 taste bud cell types
- Sustenacular cells
- Gustator cells
- Basal cells
All taste bud have?
Microvilli
How are microvilli “taste hairs”?
Extend into taste pore
If you hear sustenacular cells, you should think?
Supporting
Basal cells are?
Germinal → can become sensory or gustatory
Each taste bud has ___ cells?
50-100
Taste buds detect 5 categories of tastans
- Salty
- Sour
- Sweet
- Bitter
- Umami
What tastes salty?
Sodium ions
What tastes soure?
Hydrogen ions from acids
What tastes sweet?
Alkaloids and certain toxins
What tastes bitter?
Alkaloids and certain toxins
What taste umami?
AAs like glutamate
Dogs can detect what tastants?
- Salt
- Sour
- Sweet
- Bitter
- Neutral (water)
Brachy means?
Short
Brachydont growth
No growth after completion of eruption
Parts of brachydont
- Crown
- Neck
- Root
Who has brachydont teeth?
Carnivores
Hypso means?
Height
Hypsodont gorwth
Continuously erupting → no definite crown, neck and rook
Who has hysodont teeth?
- Ruminant cheek teeth
- All Equine
- Rodent incisor
- Canine teeth of pigs
- Elephant tusk
Enamel hardness
Hardest part of human body
Enamel consists of?
96% hydroxyapatite
Any collagen in enamel?
No
Enamel secreted by?
Ameloblasts
Dentin hardness
Harder than bonde
Dentin consists of?
70% hydroxyapatite
Any collagen in dentin?
Type I
Dentin secreted by?
Odontoblasts
Cementum hardness
Resembles bone
Cementum consists of?
45% hydroxyapatite
Any collagen in cementum?
Type I
Cementum secreted by?
Cementoblasts
Dental calculus
Formed by plague accumulation
Calculus aka?
Tarta
Dental calculus can lead to?
Periodontal disease
4 stages of tooth development
- Dental lamina
- Tooth bud
- Enamel organ
- Bell
What is the dental lamina stage?
Oral epithelium invades underlying mesenchym of jaw as dental lamina