Nutrition

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Nutrition Digestion

• Ch.18

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Nutrition

• Nutrition process by which we obtain food
• Nutrients substances used in metabolism.
• Nutrients obtained thru major food groups.
• Bread/Cereal
• Fruit/Vegetable
• Meat/Fish/Poultry
• Dairy
• Oils/Fats

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Types of Nutrition

• Autotrophs can make their own food
• Heterotrophs cant make their own food

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Types of Digestion

• Mechanical
• Break food into smaller pieces.
• Increases surface area for digestion.
• Chemical
• Breaks down food molecules into their basic
  building blocks. Ex) Carbs to monosaccharides
• Intracellular within the cell
• Extracellular outside the cell

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Adaptations for Nutrition

• Protozoan intracellular diges, osmosis
• Hydra osmosis, tentacles, stinging cells,
• gastro-vascular cavity.
• Earthworm alimentary canal, typhlosole
• Grasshopper gizzard/teeth, diges glands

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Basic Nutrients

• Carbohydrates monosacchrides
• Proteins amino acids
• Lipids glycerol fatty acids
• Vitamins organic cmpds needed in small amts
• Minerals inorganic ions needed in small amts
• Water most basic important nutrient

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Balanced Diet

• 2000 4000 Calories/day
• Diet should supply more than just the energy
  needed for that day.

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Human Digestive System

• 9 meters long w/ specialized sections
• Duct glands secrete to specific location
• Ductless glands individual cell secretions
• Mucus protects most surfaces

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Mouth

• Teeth mechanical digestion
• Tongue tastes food, assists swallowing
• Saliva lubricates food for swallowing,
• Mostly Water (90)
• Amylase digests Carbs to Disaccahrides

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Esophagus

• Connects mouth to stomach.
• Epiglottis covers trachea so food enters the
  esophagus when you swallow.
• Composed of circular muscles.
• Peristalsis pushes food along with a wave of
  muscle contractions.

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Stomach

• Stores food 3-4 hours
• Churns food mechanical digestion
• Gastric juice chemical digestion
• Pepsin digests proteins to large peptides
• Hydrochloric acid
• activates enzyme
• kills bacteria
• curdles milk
• Ulcers are holes in stomach lining

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Liver

• Accessory Digestive Organ
• Produces Bile emulsifies fats
• Gall Bladder stores bile excretes cholesterol

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Pancreas

• Juices digest all 3 food groups
• Amylase Carbs to disacchrides
• Lipase Fats to glycerol fatty acids
• Trypsin Proteins to small peptide chains
• Sodium Bicarbonate neutralizes acids
• Insulin regulates sugar absortion

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Small Intestine

• Digestion is completed here
• Maltase, Sucrase, Lactase digest disaccharides
• Lipase digests remaining lipids
• Eripsin completes protein digestion to AAs
• Absorption of all nutrients occurs here
• Villi increase surface area of intestine
• Microvilli are extensions of villi cells
• Blood vessels absorb water soluble nutrients
• Lacteals absorb fat soluble nutrients

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Large Intestine

• Undigestible materials pass thru here
• Water is reabsorbed
• Feces is concentrated remains
• Bacteria feed on remains and produce
• Vitamin K
• Vitamin B12
• Appendix is a vestigial organ (no function)

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Rectum

• Feces is stored here for elimination