Digestive System

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Digestive System
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Digestive System
a coiled, muscular tube (6-9 meters long)
beginning with the mouth and ending with the anus
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Digestion
process by which food is converted into soluble
forms
2 forms of digestion
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Forms of Digestion
Chemical Digestion
Physical Digestion
? mechanical breakdown of food into smaller
particles
? chemical breakdown of food by enzymes
? begins in mouth with saliva
? begins in mouth by chewing
? increases surface area of food
? mostly occurs in small intestine
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Chemical Digestion
Physical Digestion
? mechanical
? chemical
? begins in mouth by chewing
? begins in mouth with saliva
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Stages of Digestion
propels food through system
release of digestive juices
breakdown of food into molecular sizes
food molecules passing through intestinal walls
removal of undigested food
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Primary Digestive Organs
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teeth
mouth
tongue
esophagus
- transports food to stomach through the
process of peristalsis
stomach
- muscular organ that stores, mixes,
digests and controls passage of food
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Peristalsis
series of involuntary muscular contractions in
the esophagus that squeeze the food down to the
stomach
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small intestines
- coiled tube from 3 - 6m long, the major
site for digestion and absorption of nutrients
contain villi
large intestines
- 1.5 m long tube, absorbs water from
undigested material
anus
- opening for removal of feces
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Accessory Digestive Organs
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salivary glands
- secrete a chemical (enzyme) that breaks
down starch into glucose
- produces bile, which helps break down fats in
small intestines
- stores bile
gall bladder
pancreas
- secretes enzymes that break down starches and
proteins
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Accessory Digestive Organs
connected to stomach by ducts
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Digestive Disorders
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spot in stomach lining where cells are destroyed,
lining unprotected, irritated by stomach acid
ulcers
gastritis
swelling of stomach lining, caused by irritating
foods, alcohol, or bacteria
acid reflux
"back washing" of acid from the stomach into the
esophagus also called heartburn
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Review
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salivary glands
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liver
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gall bladder
pancreas
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Match the structure with the number.
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stomach
anus
esophagus
salivary glands
liver
small intestine
pancreas
large intestine
gall bladder
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Match the function with the number.
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contains enzymes for the first chemical breakdown
of food
major organ for digestion and absorption of
nutrients
stores undigestible food
mixes and stores food
the 4 accessory digestive organs
secretes enzymes for starch breakdown
transports food by peristalsis
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produces bile
contains villi
stores bile
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