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Digestive System
Why do you feel hungry?
Because your brain receives a signal that your cells need ____________
ENERGY
Digestive System• Digestive System - the organs that break
down food so that the body can use itParts of the digestive tract
mouth pharynxesophagus stomachsmall intestine large intestinerectum anus
Digestion• Digestion - the process of breaking down food so
it can pass through the digestive tract
2 types of digestion
1. mechanical digestion - crushing/mashing of food
2. chemical digestion - changing food into small particles to be absorb by the bloodstream
Digestion
• saliva - contains enzymes that begins chemical digestion (saliva changes carbohydrates into simple sugars)
• esophagus - squeezes the food and moves it into the stomach
Digestion
• Stomach - – squeezes the food with muscular contractions
(mechanical digestion)– Adds enzymes and acid to food (chemical
digestion)
Leaving the stomach the chyme is mixed with fluids from the liver and pancreas
Digestion
• small intestine - where the chyme is absorbed into the bloodstream by villi (small intestine is where most digestion takes place)
• liver - largest organ in the body– makes bile to break up fat
– stores nutrients
– breaks down toxins
Digestion
• large intestine - particles too large to be absorbed into the blood are pushed into the large intestine
How the kidney filters blood
1.Blood enters the kidney (by a large artery)2.Tiny blood vessels bring blood to the
nephrons (nephrons remove wastes from the blood)
3.As the blood flows water and nutrients are returned to the blood
4.Concentrated wastes from urine are passed to the bladder
Urinary Problems
• Bacterial infections - bacteria gets into the bladder and cause painful infections
• Kidney stones - salts and wastes collect inside the kidneys, causes stones
• Kidney disease - damage to nephrons can affect normal kidney function causing kidney disease