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Cards In This Set
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Organs of digestive system two main groups
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Alimentary canal and accessory digestive organs
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Also called the gastrointestinal tract or gust digest food breaks smaller fragments and absorbs digested fragments through lining of blood
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Alimentary canal
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Organs of alimentary canal
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Mouth pharynx esophagus stomach small and large intestine
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Accessory digestive organs
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Teeth tongue gallbladder salivary glands liver pancreas
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Simply taking food into the digestive tract usually via the mouth
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Ingestion
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Moves food through the alimentary canal, includes swallowing, which is initiated voluntarily, and peristalsis
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Propulsion
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The major means of propulsion involves alternate wave of contraction and relaxation of muscles in organ wall....squeezes food along tract and mixes
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Peristalsis
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Physically prepares food for chemical digestion by enzymes. Mechanical processes include chewing, mixing of food with saliva by tongue, churning food
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Mechanical digestion
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Rhythmic local constrictions of the small intestine..mixes food with digestive juices and increases the efficiency of absorption
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Segmentation
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A series of catabolic steps in which complex food molecules are broken down to their chemical building blocks by enzymes secreted into lumen
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Chemical digestion
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The passage of digested end products plus vitamins minerals and water from the lumen of the GI tract through the mucosal cells by active or passive trans
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Absorption
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Eliminates indigestible substances from the body via the anus in the form of feces
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Defacation
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Digestive activity is provoked by a range of mechanical and chemical stimuli
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Sensors (mechanoreceptors and chemoreceptors)...most important are stretching of the organ by food, osmolarity, ph of contents, substrates and end products of digestion
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These receptors (mechano and chemo) initiate reflexes that
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Activate or inhibit glands that secrete digestive juices into the lumen or hormones of the blood or stimulate smooth muscle of GI walls to mix lumen contents
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Mediated entirely by the local enteric or gut plexuses in response to stimuli arising in the GI tract
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Short reflexes
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