Term
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Definition
- transfers organic nutrients, minerals, and water from the external environment to the internal environment
- critical for absorption of nutrients
- tube open to the external environment
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Term
GI system
-order of structures- |
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Definition
- mouth
- pharynx
- esophagus
- stomach
- small intestine
- large intestine
- ascending colon
- transverse colon
- descending colon
- sigmoid colon
- rectum
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Term
| where majority of absorption takes place: |
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Definition
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Term
| Glandular organs in the GI system (and what they secrete): |
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Definition
salivary glands (amylase)
liver (bile salts)
gallbladder (bile)
pancreas (bicarbonate & enzymes) |
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Term
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Definition
- the dissolving and breaking down process of food so it can be more easily absorbed
- starts in the stomach region
- occurs via:
- HCl (secreted by parietal cells in the stomach)
- bile (secreted by the liver)
- digestive enzymes (secreted from exocrine glands)
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Term
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Definition
middle portion of the stomach
secretes mucus, pepsinogen, & HCl |
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Term
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Definition
| solution of partially digested food in stomach & intestinal lumen |
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Term
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Definition
contraction of large segments of colon
propels fecal matter into the rectum |
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Term
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Definition
series of stationary rhythmical contractions & relaxations of rings intestinal smooth muscle
- mixes intestinal contents |
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Term
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Definition
| secrete HCl & intrinsic factor |
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Term
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Definition
enzyme secreted by salivary glands & pancreas
- digests carbs (partially breaks down polysaccharides |
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Term
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Definition
upper portion of the stomach
- secretes mucus, pepsinogen, & HCl |
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Term
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Definition
inactive precursor of pepsin
- secreted by chief cells of gastric mucosa |
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Term
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Definition
soluble cluster of amphipathic molecules
- formed from fatty acids, 2 monoglycerides, & bile salts (during fat digestion in small intestine) |
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Term
| migrating myoelectric complex |
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Definition
| pattern of peristaltic waves that pass over small segments of intestine after absorption of a meal |
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Term
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Definition
| gastric gland cell that secretes pepsinogen |
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Term
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Definition
| smooth-muscle ring that surrounds a tube, closing the tube as muscle contracts |
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Term
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Definition
| sphincter surrounding common bile duct at its entrance into the duodenum |
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Term
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Definition
| thin cartilage flap that folds down, covering the trachea during swallowing |
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Term
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Definition
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Term
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Definition
various substances are released by organs & exocrine glands into the GI system
- aid in digestion & breakdown |
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Term
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Definition
| movement of products created by digestion from the lumen --> across epithelial cell layer --> into the blood (carbs, AA's, nutrients, water, salts) or lymph (fats, fat-soluble vitamins) |
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Term
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Definition
contractions of smooth-muscles in GI tract that mix contents & move them through the tract
- at a rate that ensures maximal digestion & absorption of nutrients |
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Term
the GI system is not designed to be selective --> it is designed to maximize the absorption of most nutrients
* everything you put in will be digested & absorbed
- regulation is dictated by volume & composition of luminal contents |
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Definition
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Term
the GI tract secretes more fluid into the lumen than is ingested
- fluid is constantly being recycled & reabsorbed
- only about 1% of luminal contents is excreted in the feces |
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Definition
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Term
| GI system has many components: |
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Definition
neural
muscular
cardiovascular |
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Term
| Structure of the GI tract wall |
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Definition
- 1 single epithelial cell layer separates the lumen from rest of body
- has neural innervation (motor, sympathetic, parasympathetic,afferent)
-has capillaries, arterioles, venules
- different types of muscles work in concert (longitudinal & circular)
- take away neural/muscular components --> food will just sit there (no processing or motility) |
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Term
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Definition
help with motility (move material through the GI system)
- contraction shortens the length of the tube |
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Term
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Definition
| help squeeze tube down (help with processing & moving food products through) |
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Term
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Definition
secrete hormones into blood
monitor intestinal content (are responsive to the luminal environment --> trigger hormonal secretion into circulation --> responses eventually come back to GI system) |
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