Digestive system Flashcards
Contain information about membrane, glands and teeth
What are the 3 extrinsic salivary glands and 1 intrinsic gland?
- parotid glands
- submandibular glands
- sublingual glands
- buccal glands
What is the difference between the parotid, submandibular and sublingual glands and their duct locations?
P - anterior to the ear between masseter muscle and skin
- parotid duct enters vestibule next to 2nd molar, upper jaw
SM - along medial aspect of mandible
- duct runs beneath mucosa of oral cavity floor - opens at base of lingual
SL - under tongue - anterior to submandibular glands
- ducts on floor of mouth
What is the buccal gland and what is unique about it?
inside the oral cavity
- not regulated; always leaking
What are the 2 types of secretory cells in the salivary glands?
- serous (watery secretion)
- mucous (think mucin secretion)
What is the difference between incisors, canines and premolars?
I - chisel-shaped for cutting
C - conical for tearing, piercing
PM - bicuspids and molar (4-5 cusps) - grinding, crushing
What is the difference between primary dentition and permanent teeth?
PD - also called deciduous, milk or baby teeth (total = 20)
PT - larger, deeper roots all but 3rd molar appear at the end of adolescents (total = 32)
What is the dental formula: permanent dentition?
a way to identify teeth ex.
2I, 1C, 2PM, 3M (upper jaw)
2I, 1C, 2PM, 3M (lower jaw)
What are the 2 major regions of the tooth?
- crown
- root
What is the structure/ location of the tooth and what happens if the enamel producing cells degrade?
above gingiva, covered in enamel (ca2+)
- since the cell that makes enamel disappears at birth, we need to go to the dentist to fix damaged enamel
Where is the location of the teeth root and how many are there for each type?
in the jawbone
- 1 root for I, C and PM (only 1st upper PM - usually 2)
- 2-3 for M
What is the composition of the root and what does it attach the tooth to?
outer surface covered by calcified connective tissue (cement)
- attaches tooth to periodontal ligament
What does gingiva attach to and what happens with age?
enamel
- recedes to sensitive cement
What is inside the pulp cavity?
- cell bodies of odontoblasts
- connective tissue
- blood vessels
- nerve fibers
What does the pulp cavity extend to?
root canal
What is similar between enamel, dentin, and cement and which ones contain collagen?
calcification and resembles bone, but is avascular
- cement and dentin
What are cavities, dental plaque and periodontal disease?
- holes in the enamel
- accumulation of bacteria (biofilm)
- first sign is gingivitis which can be caused by calculus
What is the epithelium of the pharynx and what is the muscle that attaches to it?
- stratified squamous epithelium
- pharyngeal muscle = skeletal muscles
Where does the esophagus attach to the stomach, what is important about the sphincter and what is it supported by?
- cardinal orifice
- gastroesophageal sphincter (physiological sphincter)
- diaphragm also supports sphincter
What is the gastroesophageal sphincter not regulated by?
it is not regulated by thickening of muscles like the pyloric sphincter
What are the 4 layers of the esophagus?
- mucosa
- submucosa
- muscularis externa
- adventitia
What type of epithelia makes up the mucosa and how does it change in response to opening and closing?
nonkeratinized stratified squamous cells
- submucosa folds when esophagus empty
- folds flatten during food transit
What does the submucosa contain in the esophagus?
mucus-secreting esophageal glands
What type of muscle makes up the muscularis externa?
- skeletal muscle in upper 1/3
- smooth muscle in lower 2/3
What is the function of the stomach?
initiation of protein digestion and converts contents to chyme
What is different in the esophagus?
fibrous adventitia instead of slippery serosa
Gross anatomy - What are the regions of the stomach?
- cardia
- fundus
- body
- pyloric region
What is the role of the 3 types of muscularis externa in stomach?
Longitudinal layer - shortens the length
Circular layer - prevents food moving backwards
Oblique layer - wrapping around
What are the 3 structures in the pyloric region starting from the inner stomach?
- pyloric antrum
- pyloric canal
- pyloric sphincter
What is rugae and how does it help the stomach?
small folds which allows stomach to expand
What is a unique feature of the muscularis externa of the stomach and what does this enable the stomach to do?
the oblique layer twists on itself
What structures of the epithelium of the stomach contain and what does it produce?
- goblet cells (produce mucous)
- bicarbonate- rich layer
- gastric pit (gastric juices - acidic)
What are the 3 types of cells that make up the gastric pit in the stomach lining and what do they produce?
- parietal cells
- chief cells
- enteroendocrine cells
Stomach - What is the difference between parietal cells, chief cells, and enteroendocrine cells?
- PC: HCL and intrinsic factor (absorb VB12)
- CC: pepsinogen (protein digester)
- EC: hormones (gastrin, histamine, serotonin, somatostatin)
Stomach - where are mucous neck cells located and what do they produce?
at neck of glands
- produce different types of mucin (acidic) for unknown reason
Why is the lumen of the stomach a harsh environment?
contains high conc. of HCL and proteases
What are the 3 ways the stomach protects itself?
- mucosal layer
- tight junctions to prevent leakage
- replacement of epithelial cells (they replace all of them, just incase some cells are damaged)
What happens if the mucosal layer is damaged in the stomach?
ulcers
- peritonitis caused helicobacter pylori
How does Helicobacter pylori contribute to ulcers and how it it treated?
- neutralizes HCL
- cause inflammation which damages tissue
- secretes cytotoxins - damage mucosa
- antibiotics
What is the small intestine responsible for?
absorption of virtually all nutrients and much of the water
What are the 3 parts of the small intestine and their functions?
- duodenum: shortest - harbors hepatopancreatic ampulla and sphincter
- jejunum: intraperitoneal
- ileum: leads to large intestine - intraperitoneal
What are the innervations of the small intestine when it comes to sympathetic and parasympathetic?
S - thoracic splanchnic nerves
PS - vagus nerve
What are the 3 important structural aspects to maximize absorption in the small intestine?
- circular folds: circular folds in mucosa and submucosa - increase SA and slows rate of passage
- villi: greatest absorption
- microvilli: brush boarder which increases SA to help break down into smallest unit with enzymes - ex. amino acids
