The Digestion System

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The Digestion System

• Ch 38-2 Guide
• Mechanical
• Chemical Breakdown
• Of Food for energy

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I 1) Mouth

• Mechanically breaks up food
• Chemically digests
• Carbohydrates
• Basic pH
• Enzyme amylase from salivary glands
• Wets forms bolus

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Esophagus

• Bolus movement to stomach by peristalsis
• (see video)

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2. Stomach

• Mechanically churns
• Stores food
• Chemically digests
• Acid pH
• Proteins
• Enzyme Pepsin
• Mucus Lining prevents digestion of itself !

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3. Small Intestine

• Absorption
• of food
• Digestion of
• Lipids (fats)
• Carbohydrates
• Uses Lipase Amylase from the pancreas

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4. Large Intestine

• Absorbs water vitamins
• No Digestion
• Eliminates wastes

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Barium Enema window to the intestines
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5. Salivary Glands

• Makes the salivary juices
• Contains amylase enzymes
• Basic pH
• For the digestion of carbohydrates

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6 Liver. Makes bile Stores sugar as glycogen
No food passes through the liver No digestion
takes place in the liver
Gall Bladder stores bile
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7.Gall Bladder Stores bile made by the liver

• Bile emulsifies fats
• Makes them water soluble
• In small intestine

No food passes through the gall bladder No
digestion takes place in the gall bladder
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Carters Little Liver Pills cureall

• Liver also cleanses the blood
• Carters pills claimed to cure constipation,
  headaches, skin problems???

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8.Pancreas makes digestive juicesEnzymes
Acids or bases
No Digestion in the Pancreas ! No food passes
through here
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9. Appendix vestigial organ
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Types of Digestion

• Intracellular
• Inside a cell
• Food vacuoles
• Small particles
• Examples
• Amoeba, Paramecium

• Extracellular
• In a sack or tube
• Larger food
• Then absorbed into a cell
• Humans

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Digestion Products

• Proteins
• Carbo-hydrates
• Lipids

• Amino acids subunits
• Muscle,enzymes,Hb
• Last use for food
• Simple sugar (glucose)
• Quick energy food
• 1st used
• Fatty acids glycerol
• Long term food, insulation,protection
• 2nd used for food

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Digestion

• Is
• Breaking down food
• physically chemically
• For
• The purpose of distributing small water soluble
  particles to the cells for energy

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Homeostasis

• Maintaining balance
• homosame
• stasisstate
• By constant adjustments
• For survival

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pH Proper acid or base levels

• Basic gt 7
• Digestion of carbohydrates
• lipids
• Acidic lt 7
• Digestion of proteins in the stomach

pH 2 7 8 1 0 12
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Properties of Enzymes

• Proteins
• Catalysts
• Speed reactions
• Work fast
• Denature at high temp

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Enzyme-Substrate complex
Active site where the substrate ( reaction
molecule) connects to enzyme
Active Site
Substrate
Enzyme
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Lock Key Model

• One enzyme
• for every substrate
• unique fit

Substrate
Enzyme
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Enzymes are pH specific

• Different enzymes
• Different body areas
• Different optimum pH
• Stomach acid pH
• Uses PEPSIN
• Mouth basic pH
• Uses AMYLASE

Blood
Mouth
Stomach
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Bile Made in Liver Stored in Gall Bladder

• Emulsifies fats
• Makes them water soluble
• In small intestine

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Villi Small intestine absorb food
Many finger-like villi maximize surface area
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8.Peristalsis

• Contractions of the Digestive system
• Moves food down
• Controlled by the autonomic nervous system

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Control of Digestion by the Nervous System