Term
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Definition
| to acquire nutrients (for growth, wound repair, etc) |
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Term
| Nutrient acquisition (6 places) |
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Definition
1. water (large amounts)
2. proteins, amino acids (large amounts)
3. carbohydrates (large amounts)
4. lipids (large amounts)
5. inorganic salts, metals
6. vitamins (organic compounds) |
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Term
| functions of alimentary digestive systems (3) |
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Definition
1. digest food: breaking it down into usable subunits
2. absorb food: bring those bits into system (bloodstream)
3. remove indigestible and toxic parts: excrete unusable bits |
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Term
| basic processes of digestive system (4) |
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Definition
1. digestion
2. secretion of fluids
3. absorption
4. motility: moving food through system |
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Term
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Definition
mechanical: physical breakdown of food increases it's surface area to have chemical breakdown
chemical breakdown: breaking of bonds (only has access to surface area that touches secretions) |
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Term
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Definition
mechanical: lubrication (water, ions, mucous makes up 95% of digestive secretions)
composed of
-water and ions: comes in through blood stream
-mucous: comes in through goblet cells to gastrointestinal lining
-digestive enzymes: break down bonds |
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Term
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Definition
carbohydrases, lipases, peptidases: all break down through hydrolysis
buffering: maintaining appropriate environment for enzymes
to work, secretions function to maintain proper pH and temperature |
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Term
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Definition
polysaccaridases: attack large chain carbohydrates (amylase or [cellulase: breaks down cellulose, is found in bacteria])
glycosidases: break down smaller carbohydrates, dissacharides and monosaccarides |
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Term
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Definition
| break down fats into fatty acids |
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Term
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Definition
break down proteins
endopeptidase: big to little proteins
exopeptidase: little to tiny proteins |
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Term
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Definition
how food moves through the digestive system, a transit system
adaptable, complex
the faster food moves through digestive tract, the less time it has for absorption |
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Term
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Definition
common phylogenetic design for digestive system
canal through organisms, open at both ends
allows for regional specialization (pH, storage)
can eat while still digesting |
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Term
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Definition
mouthpart: used for ingestion, diverse specialization across species
Buccal cavity: where food enters
pharynx (throat): passage to foregut
associated structuresL mechanical aid, salivary glands, tongues |
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Term
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Definition
esophagus
stomach: storage of food, start digestion
rugae: muscular folds in walls of stomach that mechanically grind food
monogastric stomach has 2 parts:
-fundus: food storage, some amylase digestion
-antrum: mixing food with secretions, start protein digestion |
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Term
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Definition
primary site of chemical digestion of proteins, fats, carbs
primary site of absorption of nutrients
three sections in typical vertebrate:
duodenum: receives secretions from liver and pancreas
jejunum
ileum |
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Term
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Definition
consolidates indigestible materials (makes feces)
last bit of water absorption |
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Term
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Definition
saliva: increase stimulated by parasympathetic nervous system , decrease stimulated by sympathetic nervous system
water
ions: Na, K, Cl, carbonate (buffers amylase to make an alkaline environment)
amylase
antimicrobial agents: prevent bacteria/viruses from entering system |
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Term
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Definition
hormone
made in G-cells (gastric pits have G-cells)
stimulated by stomach distention, protein
release regulated by pH: decreased pH, decreased gastrin
stimulates motility, release of alkaline fluid in pancreas
stimulates secretion of HCl, pepsinogen, Histamine |
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Term
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Definition
paracrine signal
comes from mast/ECL cells in parietal cells of gastric pit
stimulated by gastrin
Gastrin+Histamine stimulates HCl secretion |
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Term
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Definition
defense mechanism that kills microorganisms
increases acidity which denatures proteins
stimulated by Gastin+Histamine |
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Term
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Definition
peptidase, breaks down proteins
secreted as pepsinogen
HCl+Pepsinogen=pepsin
stimulated by Gastrin, proteins in stomach |
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Term
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Definition
produced in D-cells
stimulated by low pH
inhibits HCl, Gastrin, Histamine |
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Term
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Definition
thick mucousal layer of stomach lining
released by goblet cells |
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Term
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Definition
contains: pancreatic alpha amylase, endopeptidases, lipases, nucleases, bicarbonate (alkaline buffer)
secreted into duodenum
Functions:
1. digestive enzyme, stimulated by CCK
2. increases pH of chyme (alkaline fluid), stimulated by Gastrin and Secretin |
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Term
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Definition
hormone
produced in duodenal mucosa (wall of duodenum)
stimulated by acid in small intestine
Functions:
1. increase pancreatic alkaline fluid
2. inhibit gastric motility
3. inhibit gastric secretions from chief and parietal cells |
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Term
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Definition
hormone
produced in duodenal mucosa
stimulated by fatty acids and amino acids in duodenum
stimulates pancreatic enzyme release
inhibits gastric motility and secretions |
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Term
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Definition
produced in liver
composed of: water, bile salts, cholesterol, lecithin, inorganic salts, bile pigments
stored in gall bladder
stimulated by CCK, which causes contraction of gall bladder (release of bile into chyme in duodenum)
Function:
1. acts as a buffer
2. waste removal |
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Term
| Intestinal Juice (Succus Entericus) |
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Definition
alkaline fluid produced in the intestine
-Brunner glands: secrete in duodenum
-Crypts of Lieberkuhn: secrete in small intestine
stimulated by distention reflex |
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Term
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Definition
submucosa: tissue for structure
mucosa: absorptive layer, can use endocytosis to absorb
longitudinal muscle
circular muscle
circular fold |
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Term
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Definition
has thick, circular layer and projections into mucosa
increased surface area allows for mucosa attachment |
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Term
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Definition
has villi inside that increase surface area for absorption
within each villus is a capillary bed and lymph system that provides blood circulation in the intestines |
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Term
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Definition
made of microvilli and glycocalyx (extensions of microvilli)
contain digestive enzymes
contain motor proteins: actin and myosin that cause microvilli to move and churn chyme, which maximizes absorption |
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Term
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Definition
| diffusion of water through open channels |
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Term
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Definition
| diffusion by transport protein |
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Term
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Definition
| transport by ATP (direct pump), linked to transport proteins |
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Term
| absorption in blood stream |
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Definition
| sugars and amino acids go through hepatic portal vein straight to liver where toxin break down occurs |
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Term
| absorption in lymph system |
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Definition
Lacteal: 80% of fatty acids diffuse into cell (in packaged version of cholesterol) into chylomicrons
chylomicrons are removed via exocytosis into lacteal |
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