GI 1: Anatomy and Histology Flashcards
what are the 2 overall homeostatic functions of the GI tract?
- process food into digested macro/micronutrients and distribute them to cells
- maintain body water and electrolyte balance
the overall homeostatic functions of the GI tract are achieved by ___(#) processes
6
what are the 4 basic processes of the GI tract?
- motility
- digestion
- secretion
- absorption
where does motility occur?
esophagus, stomach, small I and large I
where does digestion occur?
stomach, small I
where does secretion occur?
mouth, stomach, small I , liver and pancrea
where does absorption occur?
mostly in small I, but also in stomach and large I
the digestive tract includes what 7 structures?
- oral cavity
- pharynx
- esophagus
- stomach
- small intestie
- large intestine
- anus
what are the 3 parts of the small intestine?
duodenum, jejunum; ileum
what is the function of the accessory organs to the GI tract?
secrete fluids and other substances into the GI tract
what accessory organs secrete in the mouth?
salivary glands
accessory glands in the ___, ___ and ____ secrete into the small intestine
liver, gallbladder, and pancreas
what are the 4 main layers of the digestive tissue?
- mucosa
- submucosa
- muscularis externa
- serosa
what is contained in the mucosa layer?
epithelium, lamina propria, muscularis mucosae
what is contained in the muscularis externa layer?
longitudinal muscle and circular muscle
what is contained in the serosa layer?
connective tissue and epithelium
where are endocrine cell located in the gi tract?
along the epithelium that is exposed to the gut lumen
where are mucous cells located in the GI tract?
along the epithelium exposed to gut lumen
endocrine secrete into ___
internal environment
exocrine secrete into ___
external environment
epithelium cells are joined by ___ that prevent leaky gut
tight junctions
what are the 3 major functions of the mucosa and the locations they perform these functions?
- secretion (stomach)
- protection (mucous)
- absorption (small )
what type of wbc are located w/i the lymph nodules of the GI tract to help prevent disease?
GALT
the epithelium of the GI tract has what 2 types of sensory receptors?
chemical and mechanical
what is the function of the simple columnar epithelium cells>
absorb nutrients (microvili)
what is the function of enteroendocrine cells?
secrete hormones
the muscularis mucosae has ____ that increase SA and digestion / absorption
high # of folds
what is the main function of the submucosa?
elasticity
the BV and lymph nodes are ____ (smaller/larger) in the submucosa
larger
the submucosa is formed of ___ and ___ tissue
elastic and connective
there are ___, ___ and ____ found in the submucosa. As well, there are ___ in all organs except the esophagus and stomach
glands; blood vessels; lymphatic vessels; submucosal plexus
in the mouth, upper esophagus, pharynx, external and anal spincters have what layer of muscles (exception to muscularis smooth muscles)
skeletal muscles
the stomach has ___ layers of smooth muscle that include a ____layer
3; intermediate oblique
what is the function of the circular muscularis
reduce diameter
what is the function of the longitudinal layer of muscularis?
shorten tube
smooth muscle works as a single __
unit
cells in the GI tract are electrically connected to neighbouring cells by ____
gap junction
what are the 3 benefits of gap junctions in the GI tract?
- low resistance to ion movement between cells
- quick spread of electrical signals
- simultaneously contrcation of cells
the enteric nervous system is made of the __ and ___
submucosal plexus and the mysenteric plexus
what is considered the “brain of the gut”
enteric nervous system
the submucosal plexus is located in the
submucosa
the myenteric plexus is located in the __
muscularis externa
the myenteric plexus controls ___
motility
the submucosal plexus controls ___
secretion
the longitudinal and circular smooth muscle of the muscularis externa are stimulated by ___ neurons from the ___ plexus
motor; myenteric
endicrine cells and exocrine cells are stimulated by ___ neurons from the ___ plexus which are stimulated by __ neurons from the ___ plexus
motor; submucosal; interneuron; myenteric
the serous layer is made of ___ tissue
connective
what is the function of the serosa?
produce serous fluid to lubricate the exterior of the highly motile organ
the mucosal epithelium is stimulated ny ___ neurons fom the ___, ___ and _____
sensory; myenteric, submucosal; ANS to CNS neurons
