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Digestive System . Earthworm . Human. Purpose:. Takes food in, breaks food up (digestion) and excretes waste Organs : mouth, esophagus, stomach, intestines, liver, pancreas, gall bladder. Tissues. The entire digestive tract is lined with epithelial tissue that secretes mucus
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Earthworm Human
Purpose: • Takes food in, breaks food up (digestion) and excretes waste • Organs: mouth, esophagus,stomach, intestines, liver,pancreas, gall bladder
Tissues • The entire digestive tract is lined with epithelial tissue that secretes mucus • Functions of mucus: • Protects tissue from digestive enzymes • Allows material to pass smoothly along tube
Did you know? If you eat spoiled food, your body recognizes the presence of toxins and attempts to remove as quickly as possible. You experience this as vomiting or diarrhea.
Mouth • Mechanical digestion • Breaks food down by chewing • Chemical digestion • Enzymes in saliva breakdown molecules of food
Esophagus • Muscular tube connecting mouth and stomach • Smooth muscle tissue:can contract without conscious thought • Peristalsis
Stomach • Mechanical Digestion • Stomach churns food • Chemical Digestion • Very strong acid (pH 2) • Digestive enzymes • Contains many nervesthat tell us when we’re full
Did you know? • Heartburn occurs when stomach acid backs up into your esophagus • Your esophagus does not have the thick mucous layer that protects your stomach and this results in a burning sensation • Treatment caninclude taking anantacid toneutralize theacid
Small Intestine • 6m long and 1.5 cm in diameter • Site of most digestion • Goblet cells secrete mucous • Nutrients diffuse through thewall of the small intestineinto the bloodstream
Did you know? • Mucus in the goblet cells expands rapidly when released from the cells • Mucous can increase in volume up to 500 times in 20 ms!
Large Intestine • 1.5m long and 6cm in diameter • Absorbs water from indigestible food • Remaining solid matter is excreted as feces from the anus
Accessory Organs • Liver • Secretes bile whichhelps to emulsify fats(mechanical digestion) • Gallbladder • Stores bile • Pancreas • Produces insulin which regulates the concentration of glucose in the blood
Label your digestive system diagram with the following labels
Homework • Finish digestive tract activity and label all organs • pg 82 #2, 4, 5