Nutrients and Digestion

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Chapter 2

• Nutrients and Digestion

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Nutrients

• Usable parts of food that provide energy and
  materials for cell growth, development, and
  repair
• Calories- measurement of energy in food
• Amount of energy to change 1kg water by 1oC
• Energy needs
• Muscles
• Body temperature

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Classes of Nutrients

• Organic- proteins, carbs, fats, vitamins
• Inorganic- H2O, minerals

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Proteins

• replace and repair body cells
• Large
• Made of amino acids

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Carbohydrates

• Main energy source
• Sugars
• Starch
• fiber

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Fats

• aka Lipids
• Energy
• Absorb vitamins
• Cushion
• Cell membrane

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Vitamins

• Organic
• Growth
• Regulate body functions
• Prevent some diseases

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Minerals

• Inorganic nutrients
• About 14 used
• Build cells
• Nerve impulses
• Trace minerals- use small amounts

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Water

• Humans 60-65 weight is water
• About 2/3 in cells
• Lose
• sweat
• Exhale
• wastes

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Food Groups

• Foods grouped if they have the same type of
  nutrient

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Food Pyramid
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Daily Servings

• 6-11 bread, cereal
• 3-5 veggies
• 2-4 fruit
• 2-3 milk
• 2-3 meat and beans
• Small amounts fats, oils, sweets
• Size of serving differs

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Food Labels

• Tell serving size
• Calories
• Vitamins, minerals
• fats

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Section 2- Digestive System

• Processes food
• Ingestion- taking in of food
• Digestion- process that breaks down food into
  particles the body can use
• Absorption- materials moved into blood and then
  into cells
• Elimination/egestion- unused portions or wastes
  pass out of the body

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Types of Digestion

• Mechanical- physically breaking down food
• Chemical- chemically breaking down food

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Enzyme

• Any protein that speeds up the rate of a chemical
  reaction in your body

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Digestive System Organs

• Mouth- esophagus- stomach- small intestine- large
  intestine- rectum- anus
• Accessory organs- salivary glands, liver,
  gallbladder, pancreas

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Mouth

• Mechanical digestion
• Chewing
• tongue
• Chemical digestion
• Saliva breaks down starch into sugar

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Esophagus

• Passes over trachea
• Tube about 25cm long
• No additional digestion
• Peristalsis- keeps food moving through tract
• Contractions of digestive organs

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Stomach

• Muscular, J-shaped
• Expands
• Mechanical digestion
• Chemical digestion- acid, enzymes
• 2-4 hours in stomach
• Makes chyme- thin watery liquid

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Small Intestine

• Small because of diameter
• Actually 13-23 feet in length
• Duodenum is 1st part
• Most digestion here
• Gets enzymes from liver (via gallbladder) to
  digest fats
• Enzymes from pancreas to break up fats, carbs,
  proteins

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Small Intestine

• Small projection called villi
• Increase surface area
• peristalsis

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Large Intestine

• Receives undigested and unabsorbed material
• Mostly absorbs water, vitamins, and minerals
• Peristalsis slows down
• Rectum is end to store feces
• Feces go out the anus

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Bacteria are IMPORTANT

• In digestive tract
• Mouth
• Large intestine
• Jobs
• Break down undigested material
• Make vitamins
• K- blood clotting
• 2 Bs- nervous system