Digestive System I Histo Flashcards
the digestive system consists of ____ and ____
alimentary canal (or GI tract) and associated or accessory digestive organs
organs of the GI tract include:
mouth, most of pharynx, esophagus, stomach, small intestine, large intestine
associated or accessory digestive organs
tongue (PB), teeth (PB), salivary glands (S), pancreas (S), liver (S), and gallbladder (S)
major processes of the digestive system
- ingestion
- secretion
- mixing and propulsion (motility capability)
- digestion (mechanical and chemical)
- absorption
- defecation (of feces)
- barrier
- immunologic protection
the oral cavity opens into the oropharynx through an opening called the ____
fauces
between the lips and teeth and between the cheeks and teeth
vestibule
parts of the oral cavity are:
- vestible
2. oral cavity proper
____ produce dentin, ____ produce enamel
odontoblasts; ameloblasts
saliva is ___ and ____; average secretion of ___ to ____ per day
99.5% water ; 0.5% solutes; 1000-1500 ml per day
saliva has protective and digestive roles:
- moisten oral mucosa
- moisten dry foods
- provide medium for food materials to dissolve so they can chemically stimulate taste buds
- buffer contents of oral cavity (bicarbonate and phosphate ions)
- contains amylase that partially breaks down starch (i.e. polysaccharides)
the pharynx connects nasal and oral cavities to the ___ and ____; is a passageway for ___ and ___
larynx; esophagus; food; air
pharynx has respiratory epithelium (which is ____) and some _____
ciliated pseudostratified columnar epithelium; nonkeratinized stratified squamous epithelium
3 parts of the pharynx
nasopharynx, oropharynx, and laryngopharynx
nasopharynx has _____ bc it is an air passageway only; it is superior to the ____
ciliated pseudostratified columnar epithelium; soft palate
when swallowing, the ___ and ____ move superiorly to close off the nasopharynx
soft palate; uvula
the oropharynx has _____ because it is an air and food passageway; it is posterior to the oral cavity between level of ____ and ____
nonkeratinized stratified squamous epithelium; soft palate; epiglottis
the laryngopharynx has ____ bc it is an air/food passageway; it is continuous with both the ___ and ____; extends from ____ to ____
nonkerat. strat. squamous epithelium
esophagus; larynx
upright epiglottis; larynx
organization from lumen outward of alimentary canal
- mucosa (lining epithelium, lamina propria, muscularis mucosae)
- submucosa
- muscularis externa
- serosa or adventitia
lining epithelium of the mucosa can either be ____ or ____
nonkeratinized stratified squamous epithelium; simple columnar epithelium
lamina propria is ____
loose (areolar) connective tissue
muscularis mucosae is _____
smooth muscle tissue
submucosa is ____ and contains ____
dense irregular connective tissue; meissner’s plexus/submucosal plexus
smooth muscle of the muscularis externa contains inner ___ layer and outer ____ layer
circular; longitudinal
inner circular layer can be thickened to form ___ or ____
sphincters; valves
muscularis externa contains ___ nerve plexus or ____ plexus
myenteric; Auerbach’s
serosa, or visceral peritoneum, is made of ____ and ____
mesothelium (simple squamous epithelium)
loose (areolar) connective tissue
adventitia is made of _____
loose (areolar) connective tissue)
the mucosa of the esophagus is _____
nonkeratinized stratified squamous epithelium
muscularis externa of the esophagus is ____ in the upper third, ____ in the distal third, and the middle third is mixed
skeletal muscle; smooth muscle
most of the outer portion of the esophagus is ____ because it is mostly in the thorax, but the portion of the esophagus that enters the peritoneal cavity is ____
adventitia; serosa
mucous glands in the submucosa of the esophagus
esophageal glands (proper)
mucous glands in the lamina propria of the esophagus
esophageal cardiac glands
the cardia of the stomach has cardiac glands that secrete primarily ____
mucous
the fundus/body of the stomach has fundic glands that contain cells that secrete ____ and ____
HCl; pepsin
the pylorus of the stomach has pyloric glands that secrete primarily ____
mucous
the mucosa of the stomach is ____ or _____
simple columnar epithelium; surface mucous cells
gastric pits lead to _____ glands
simple branched tubular glands
3 layers of smooth muscle in the muscularis externa of the stomach
- outer longitudinal
- middle circular
- inner oblique
outer layer of stomach covered with ____
serosa
the tubular glands of the stomach do not go past the ____ layer
muscularis mucosae
3 parts of the fundic glands that are in the fundus/body of the stomach
isthmus, neck, and base
isthmus part of the fundic glands has ____ population
stem cell
neck region of a fundic gland has ____ which secrete mucous
mucous neck cells
parietal cells secrete ___ and ____; they are ____ cells that have a lot of mitochondria
HCl; intrinsic factor; eosinophilic
chief cells or zymogen cells secrete ____ and _____
pepsinogen (which is converted to pepsin) ; gastric lipase
G cells (or enteroendocrine cells) which are at the base of fundic glands secrete hormones like ____
gastrin
