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99 Cards in this Set
- Front
- Back
Function is to process food, extracts nutrients, eliminates the residue |
The Digestive System |
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the selective intake of food |
ingestion |
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The physical breakdown of food into smaller particles. Exposes mere surface area to enzymatic action. |
mechanical digestion |
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Employs enzymes to breakdown macro-molecules into basic building blocks. |
chemical digestion |
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All chemical digestion is a process of |
enzymatic hydrolysis |
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breaking covalent bonds by adding water |
enzymatic hydrolysis |
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The uptake of nutrient molecules into the epithelial cells of the digestive tract, then into the blood & the lymph |
absorption |
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the absorption of water & the compaction of indigestible residue into feces. |
compaction |
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the elimination of feces |
defecation |
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16' tube. opens to ext. environment-both ends. Includes the mouth, pharynx, esophagus, stomach, small & large intestines. |
the digestive tract |
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stomach & intestine are part of..... |
GI tract |
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teeth, tongue, salivary glands, liver, gall bladder, and pancreas. |
accessory organs |
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the oral or buccal cavity. function: ingestion, taste, chewing, mechanical& chemical digestion, swallowing, speech, respiration. |
the mouth |
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surface is covered with non-keratinized stratified squamous epithelium w/bumps called lingual papillae. |
tongue |
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anterior 2/3 of the tongue is called.....and occupies the oral cavity |
the body |
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posterior 1/3 of the tongue is called......and occupies the first part of the pharynx. |
the root |
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This helps close the trachea by pushing the epiglottis back |
the tongue |
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collectively called the dentition. sever to masticate the food, breaking it up into smaller pieces for enzymatic breakdown |
teeth |
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adults typically have .....teeth in the mandible and maxilla. |
16 |
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most of a tooth consists of a hard, yellowish tissue called |
dentine |
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teeth are covered by.......in the crown and .......in the root |
enamel; cementum |
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non-living hardened secretion |
enamel |
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living connective tissue |
dentine & cementum |
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damaged dentine or cementum can regenerate but when this is damaged it cannot and must be artificially repaired. |
enamel |
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a watery solution of mucus, enzymes & electrolytes. moistens mouth, cleanses teeth, lubricates food, inhibits bacterial growth, dissolves molecules so they can stimulate taste buds |
saliva |
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anterior to ear lobes ducts open into mouth opposite 2nd molar "mumps"-inflammation of this gland |
parotid |
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1/2 way along medial side of mandible ducts open beneath tongue |
submandibular |
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floor of mouth multiple ducts empty beneath tongue |
sublingual |
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a muscular funnel that connects oral cavity to esophagus nasal cavity to larynx |
pharynx |
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point of intersection for digestive & respiratory tracts |
pharynx |
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straight muscular tube 25-30 cm long. begins posterior to trachea at inferior border of the larynx. |
esophagus |
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the esophagus penetrates the diaphragm at this structure |
esophageal hiatus |
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the esophagus meets the stomach at the |
cardiac orifice |
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prevents stomach contents from regurgitating |
lower esophageal sphincter |
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acid reflux into esophagus |
heart burn |
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involves over 22 muscles in mouth, pharynx, esophagus. coordinated by "swallowing center in medulla oblongata. |
swallowing "deglutition" |
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voluntary tongue collects food into a bolus & pushes posteriorly
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oral phase |
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food accumulates in.......in front of epiglottis |
oropharynx |
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epiglottis tips posteriorly & bolus slides into |
laryngopharynx |
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involuntary initiated by bolus activating touch receptors in laryngopharynx. Pharyngeal constrictors drive bolus down into esophagus. breathing is automatically suspended for a moment during this phase |
pharyngeal phase |
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esophagus constricts behind bolus while re relaxing in front of bolus thus propelling bolus downward |
esophageal phase |
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wave of involuntary contractions during esophageal phase of swallowing |
peristalsis |
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when standing gravity works faster than |
peristaltic wave |
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ensures that you can swallow regardless of body postition |
peristalsis |
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liquids reach stomach in .......seconds |
1 to 2 |
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bolus reach stomach in .........seconds |
4 to 8 |
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As bolus reaches lower end of esophagus........relaxes to let bolus pass into stomach |
esophageal sphincter |
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muscular sac in the upper left abdominal cavity inferior to the diaphragm |
stomach |
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functions primarily as a food storage organ |
stomach |
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mechanically breaks down food particles liquifies food begins chemical digestion of proteins and fats |
stomach |
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a pasty mixture of semi-digested food in the stomach |
chyme |
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stomach is j shaped & divides into these 4 regions. |
cardiac, fundic, body, and pyloric region. |
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most inferior region of the stomach. terminates at the pylorus |
pyloric region |
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surrounds the pyloric region and regulates passage of chyme |
pyloric sphincter |
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Gastric glands produce 2-3 liters of gastic juice per day |
gastric secretions |
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produced by parietal cells, activates pepsin, converts dietary iron into usable form, breaks up CT, contributes to disease resistance |
HCL |
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produced by chief cells called pepsinogens and digests proteins to shorter chains |
pepsin |
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produced by chief cells and digest fats |
lipase |
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produced by parietal cells essential for the absorption of vitamin B 12 w/out B 12, hemoglobin cannot be synthesized.
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intrinsic factor |
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the only indispensible function of the stomach |
intrinsic factor |
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the forceful ejection of stomach contents |
vomitting |
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vomitting is controlled and integrated by this center located in the medulla oblongata |
emetic center |
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why doesnt the stomach digest itself? |
1. mucosa covered w. a thick, highly alkaline mucus that neutralizes HCL & resists enzymes. 2. tight junctions between epithelial cells. 3. rapid epithelial cells replacement. 3-6 days. |
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small pear shaped organ on the posterior inferior portion of the liver |
gallbladder |
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the gallbladder stores and concentrates this substance produced by the liver. |
bile |
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yellowish green fluid containing minerals, cholesterol, phospholipids, bile pigments, bile acids. |
bile |
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principal pigment in bile derived from decomposition of hemoglobin |
bilirubin |
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steroids synthesized from cholesterol. Aids in the breakdown of fats and their absorption. |
bile acids (salts) |
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if bile becomes excessively concentrated they many form these |
gallstones |
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both and endocrine and exocrine gland-sugar regulation |
the pancrease |
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endocrine (1%) |
islets of langerhans insulin,glucagon
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99% of pancreas is........with a digestive function |
exocrine |
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secretes @ 1500 ml of pancreatic juices per day |
pancreas |
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the pancreas flows to the duodenum(small intestine) vial the............to join the bile duct |
pancreatic duct |
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pancreatic juice is alkaline(to buffer HCL) and consists mainly of |
enzymes |
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digests proteins |
trypsin & chymotrypsin |
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digests starch |
pancreatic amylase |
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digests fat |
pancreatic lipase |
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digests RNA |
ribonuclease |
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Deoxy ribonuclease |
digest DNA |
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a coiled mass filling most of the abdominal cavity. divided into 3 regions: Duodenum, Jejunum, Ileum. |
small intestine |
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first 25 cm of the small intestine. begins at pyloric valve secretes an abundance of mucus to neutralize the stomach acids. |
duodenum |
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stomach acids neutralized fats broken up by bile acids. Pancreatic enzymes begin chemical digestion. |
emulsified |
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most digestion & nutrients absorption occurs here |
jejunom |
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end at the cecum (large intestine) and the passage of food residue is controlled here by the ileocecal valve |
ileum |
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ring-like constrictions appear at several places along the intestine as they relax, new constrictions appear elsewhere.
the purpose is to knead or churn the intestine contents |
segmentation |
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when most nutrients have been absorbed & what is left is undigestible residue, segmentation declines and peristalsis begins, thus moving material towards the colon. |
peristalsis |
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receives @ 500 ml of indigestible food residue per day. reduces this to @ 150 ml of feces by absorbing water and salts |
large intestine |
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begins in the lower right quadrant at the ileocecal valve |
large intestine |
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start of the large intestine. The appendix attaches to it. |
cecum |
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highly populated with lymphocytes and is a significant source of immune cells |
appendix |
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the portion of the large intestine between the ileocecal valve and the rectum. |
colon |
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we house over 800 species of bacteria here, which digest substances that we do not have enzymes for |
colon |
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bacteria also synthesizes....... |
B-vitamins and Vitamin K |
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used for clotting blood our diet alone does not provide enough to ensure adequate blood clotting |
Vitamin B & K |
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takes 12-24 hours to reduce the residue of a meal to feces |
absorption and motility |
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75% water 25% solids |
feces |
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clonic motility is predominantly a type of segmentation |
haustral contractions |
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pouches in the large intestine |
haustra |