KEY CONCEPT Cells require many different nutrients.

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KEY CONCEPTCells require many different
nutrients.
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The six types of nutrients are water,
carbohydrates, proteins, fats, minerals, and
vitamins.

• Water makes up 55 to 60 of your body.
• involved in nearly every cell and body process
• need 2 liters (8 cups) a day to replace fluid lost

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• Carbohydrates are the main source of energy for
  the body.

• simple and complex carbohydrates supply glucose
• fiber from plant foods helps elimination

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• Proteins are necessary for growth and repair of
  the bodys cells.

• body makes 12 out of 20 amino acids
• other eight essential amino acids come from food
• Fats provide energy and key building components.
• fats are saturated and unsaturated
• essential fatty acids come from food

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• Minerals are inorganic materials.

• help to build or repair tissues
• replenished by eating variety of foods

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• Vitamins are organic molecules that work with
  enzymes.

• vitamins are fat-soluble and water-soluble
• regulate cell functions, growth, development
• replenished by eating variety of foods

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Meeting nutritional needs supports good health.

• During puberty, you require more nutrients and
  Calories.

• One Calorie equals one kilocalorie, or 1000
  calories.
• 1g of protein or carbohydrate equals 4 Calories.
• 1g of fat equals 9 Calories.

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• A balanced diet of whole foods provides the best
  nutrients and Calories.

• Food and physical activity also need to be
  balanced.

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• Food labels can help you make good eating
  choices.

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KEY CONCEPT 32.2The digestive system breaks down
food into simpler molecules.
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Several digestive organs work together to break
down food.

• The digestive system breaks down food into energy
  cells can use.
• After digestion is complete, nutrients are
  absorbed and transported to all cells.
• Undigested materials are eliminated as liquid and
  solid wastes.

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Digestion begins in the mouth and continues in
the stomach.

• Mechanical and chemical digestion break down
  food.
• Peristalsis moves food through the organs.

muscles contract
stomach
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• Digestion of carbohydrates begins in the mouth.

• Digestion of proteins occurs in the stomach.
• Digestion of fats and sugars occur in thesmall
  intestine.

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Digestion is completed in part of the small
intestine.

• Most digestion takes place in the duodenum.
• The pancreas, liver, and gallbladder aid in
  digestion.
• pancreas helps digest fat and protein
• bile from the liver/gallbladder helps digest fats

liver
stomach
bile
chyme
bile
enzymes
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KEY CONCEPT 32.3Nutrients are absorbed and solid
wastes eliminated after digestion.
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Most absorption of nutrients occurs in the small
intestine.

• Three structures in the small intestine help
  absorb nutrients.
• folded lining adds surface area, slows food
• villi absorb nutrients
• microvilli cover villi, absorb nutrients

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• Duodenum, jejunum, and ileum absorb different
  nutrients.

• Nutrients enter the circulatory or lymphatic
  systems.
• Liver stores excess glucose for future use.

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Water is absorbed and solid wastes are eliminated
from the large intestine.

• The colon helps to maintain the bodys fluid
  balance.
• Undigested material forms the solid feces.
• stored in rectum
• eliminated through anus

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• The large intestine contains many bacteria.

• some synthesize important vitamins
• Some, like E. coli, can cause illness

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KEY CONCEPT 32.4The excretory system removes
wastes and helps maintain homeostasis.
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The excretory system eliminates nonsolid wastes
from the body.

• Nonsolid wastes are eliminated through lungs,
  skin, and kidneys.
• Lungs exhale carbon dioxide and water vapor.
• Sweat glands in skin release excess water and
  salts.
• Kidneys filter and clean the blood to produce
  urine.

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The kidneys help to maintain homeostasis by
filtering the blood.

• Kidneys are a pair of bean-shaped organs.
• two layers medulla and cortex
• filtering units called nephrons
• renal artery and renal vein

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• Kidneys have three basic functions in maintaining
  homeostasis.

• remove waste from blood
• help to maintain electrolyte, pH, and fluid
  balances
• release key hormones

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Nephrons clean the blood and produce urine.

• Nephrons are the filtering units in the kidneys.
• They clean and rebalance the blood to produce
  urine.

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• Nephrons clean the blood in a three-step process.

• The first step is filtration of the blood.

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• The first step is filtration of the blood.

• The second step is reabsorption of materials.

• The third step is excretion of materials.

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Injury and disease can damage kidney functions.

• A kidney transplant can replaced damaged kidney.

• recipient and donor tissue must match
• drugs prevent tissue rejection

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• Dialysis can be used to filter and clean the
  blood.