NN+Digestive+System+Notes

WHY DO WE EAT
 * to provide our bodies with energy
 * break down matter, so have to replace broken down matter
 * cells are always dying, so need to replace them
 * need to eat certain nutrients to rebuild cells
 * common problem is that we eat too many calories

FATS
 * stores long term energy
 * makes the cell membrane
 * bad fats
 * saturated fat: found in animals. is solid at room temperature
 * trans fat: the worst fat. human chemically change plant fat

CHOLESTEROL
 * LDL/low density lipoproteins are very bad
 * HDL/high density lipoproteins are good

CARBOHYDRATE
 * fiber=good carb (comes from a plant)
 * not straight sugar
 * straight sugar is very bad

PROTEIN
 * everything cells do is done by protein
 * DNA codes for proteins
 * VERY IMPORTANT
 * built with amino acids
 * eat protein to have amino acids so that we can make our own proteins
 * only make 10 amino acids, have to eat the other 10 "essential amino acids" or die.
 * 10 essential amino acids
 * eat animals especially their muscles
 * vegetarians should eat:
 * dairy
 * eggs
 * beans
 * wheat
 * rice
 * legumes
 * maize
 * pulses
 * can't have too much protein

VITAMIN A
 * associated with eyes
 * helps vision

VITAMIN C
 * prevents scurvy
 * makes a protein called collagen
 * 25% of protein in the human body is collage
 * filler protein

CALCIUM
 * builds bones

IRON
 * for red blood cells
 * makes you feel tired
 * makes you anemic

DIGESTIVE SYSTEM
 * begins in the mouth
 * digestive track is about 20 ft long
 * food inside the digestive system is not considered a part of you
 * mouth breaks food down to small pieces, but not small enough to be digested (except sugar)
 * food goes down tube and enters stomach
 * food broken down by acids in the stomach, more mechanical breaking down.
 * still can't be digested (except protein, but protein isn't absorbed yet)
 * food goes to small intestine
 * finishing breaking down the food
 * some food is absorbed
 * goes to large intestine
 * some of the other food absorbed
 * fiber is not absorbed, but friendly bacteria eat them
 * water is absorbed
 * diarrhea occurs when body doesn't absorb the water
 * can kill young children b/c they become dehydrated
 * 33 hrs for food to go through the digestive system