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41 Cards in this Set

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  • Back
What are the primary organs of the GI tract (alimentary canal)?
mouth
pharynx
esophagus
stomach
small intestine
large intestine
anus
what are the accessory organs of the GI tract
teeth
tongue
gallbladder
salivary glands
liver
pancreas
What are the 4 major layers (tunics) within the digestive tract wall?
mucosa (inner most)
submucosa
muscularis externa
serosa
what layer is the primary site for absorption into the blood?
submucosa
list the 6 parts of the digestive process
ingestion
propulsion
mechanical digestion
chemical digestion
absorption
defecation
contraction and relaxation that moves food (bolus) through the alimentary canal
peristalsis
part of the GI tract where most of the water is absorbed
large intestine
how are luminal conditions controlled in order to make the process as effective as possible?
2 ways
Intrinsic controls
mechanical and chemical stimuli such as stretch receptors, osmolarity, pH

Extrinsic controls
the central nervous system
what are the 2 kinds of digestive reflexes?
Short reflexes local effect

Long reflexes (brain) stimulus goes to brain and then a response is made
what are the 4 boundaries of the oral (buccal) cavity?
anterior
inferior
lateral
posterior
lips
tongue
cheeks
oropharynx
the ____ forms the roof of the mouth and is rough to promote mechanical digestion through friction.
2 parts
palate

hard palate closer to teeth
soft palate back of the mouth
what part of the mouth prevents swallowing the tongue?
lingual frenulum
the tongue has both _____ and _____ skeletal muscles
intrinsic- change of shape, initiate swallow
extrinsic- upward, side to side. attached to bone
what are the 3 extrinsic (outside oral cavity) salivary glands?
parotid
submandibular
sublingual
what is the composition of saliva?
95.5% water
.5% ions/enzymes

amylase (breakdown polysaccharides)
lingual lipase
lysozyme (breakdown cell walls)
the salivary glands are composed of 2 types of secretory cells, _____ and ____
mucus
serous

to lubricate the oral cavity
3 portions of the pharynx
oropharynx
nasopharynx- respiratory
laryngopharynx
there are __ muscles involved in the swallowing reflex
25
3 parts of the swallowing reflex

involuntary and voluntary
oral- voluntary
pharyngeal- involuntary
esophageal- involuntary
swallowing is initiated voluntarily and then as the bolus reaches the _____ it becomes involuntarily thorugh the ____
laryngopharynx
medulla
the ___ bone blocks entry to the trachea
hyoid
the esophagus connects the ____ to the _____
pharynx
stomach
both the esophagus and pharynx contain stratified _____ epithelium
squamous
the esophagus contains an _____ and ______ to prevent acid reflux, heartburn, vomiting
upper esophageal sphincter
lower esophageal sphincter

not a true sphincter, although rodents have actual ones and cant vomit
the stomach is __ to __ inches in length, it is 50ml empty but can expand to __ liters of food
6-10
4
the stomach converts food into a creamy paste called ____
Chyme
2 major parts of the stomach
body (contains cardia region)
pyloric- atrium region
the ___ valve regulates emptying into the ______ and into the small intestine
pyloric
duodenum
outlet for the gastric glands
gastric pits
cells that secrete HCL to give the stomach a pH of 2
parietal cells
how do the parietal cells secrete gastric acid?
through proton pumps
Cl- moves into the cell, allowing HC03 to leave (secondary active trans)
Cl- moves into the stomach (facilitative diffusion)
H+ moves into stomach as K+ moves into cell from stomach (primary active trans)
how do drugs like prilosec prevent acid reflux?
by blocking the proton pumps
parietal cells have an intrinsic factor that is needed for vitamin ___ ileal absorption for erythrocyte creation
B12
Chief cells release _______ which is inactive, and form _____ by breaking peptide bonds
pepsinogen
pepsin (active)
enterochrommaffin like cells (ECL) release _____ and ______
histamine and serotonin
4 types of gastric secretions
what cells do they come from?
Gastrin- G cells
Somatostatin- D cells
serotonin- ECL
Histamine- ECL
stimulates gastric acid secretion and promotes gastric mucosal growth
gastrin
stimulates HCL secretion
Histamine
increases gut contractility
serotonin
suppresses release of gastrin, cck, secretion
reducing gastric emptying and contractions
somatostatin
lines the stomach to protect from acidity. causes the pH of fluid around the border to be closer to neutral
gastric mucosal barrier.

bicarbonate rich mucus walls
epithelial cells with tight junctions
surface epithelial replaced every 3 days