Digestive System http://health.howstuffworks.com/adam-200142.htm

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Digestive Systemhttp//health.howstuffworks.com/
adam-200142.htm

• Swenson

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(No Transcript)
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Salivary Glands

• Secrete enzyme amylase (breaks down carbs)
• cover food to produce bolus (Mucous lubricates
  food)

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Tongue

1. moves food side to side to be chewed and keeps
   between teeth
2. moves bolus to back of throat
3. closes off mouth when swallowing

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Trachea

1. Wind Pipe
2. Epiglottis flap of skin that covers the trachea
   so food does not enter the wind pipe and cause
   you to choke.

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Esophagus

• a. Food to the stomach by peristalsis

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Liver

1. produces and secretes bile which emulsifies fats
2. detoxifies blood
3. stores glycogen (animal form of starch)
4. Reduces/neutralizes acidse. bile breaks up fats

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Gall Bladder

• a. Stores bile

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Stomach

1. churn/mix food
2. digestion of proteins starts here
3. Gastric juice is acidic (HCl) and contains pepsin
   (enzyme to digest proteins)
4. Gastrin (hormone) stimulates to release of
   gastric juice
5. vomiting-reverse peristalsis
6. pyloric sphincter controls opening and end of
   stomach

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Bile Duct

• a. duct or tube from gall bladder to small
  intestine

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Trachea

1. wind pipe
2. protected by epiglottis during swallowing
   (covering)

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Small Intestine

• 20 30 feet long
• parts of sm. Intestine are
• duodenum listed above
• jejunum has folds of skin called the brush
  border membrane.
• ileum selective absorption of some nutrients.
  What remains is liquid stool
• Final digestion occurs here
• food is absorbed in simplest forms amino acids,
  fatty acids, glycerole.
• Villi small finger like projects that contain
  vessels to absorb food

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Duodenum

• a. Most of the digestion begins here (proteins,
  fats and carbs)

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Pancreas

1. produces powerful digestive enzymes
2. Produces and secretes insulin important in
   regulating blood sugar levels

Pancreas Duct a. A duct or tube from pancreas
to small intestine
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Appendix

• Vestigial organ dead end
• a. May at one time have aided in digestion of
  cellulose but has no function today

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Large Intestine (colon)

1. Parts are Cecum large entrance controlled by a
   sphincter that protects the small intestine from
   the large intestines concentrated bacteria,
2. Ascending colon upwards,
3. Transverse colon across,
4. descending colon down,
5. sigmoid colon end

f. reabsorbs water g. Some solid wastes are
stored before they enter rectum
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Rectum

• Rectum
• a. Stores solid waste until full
• Anus
• a. Controlled by sphincter muscle by peristalsis.

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Digestion animation review

• http//highered.mcgraw-hill.com/sites/0072495855/s
  tudent_view0/chapter26/animation__organs_of_digest
  ion.html

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Digestive Processes

• I. Ingestion
• Takes food in mouth
• II. Peristalsis
• a. Muscular contractions along digestive
  tract-esophagus ? small and large intestine

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• Absorption
• Taking of digested food into blood stream
• Occurs in Sm. Intestine
• Storage
• Animal starch stored as glycogen in liver
• Elimination
• Solid waste eliminated from large intestine

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• Mechanical Digestion
• Physically chewing-mouth
• Churning action-stomach
• Chemical Digestion
• Uses enzymes
• Starts carbohydrate breakdown in mouth
• Starts protein breakdown in stomach
• Carbohydrates, proteins, and fats are fully
  digested in Sm. Intestine

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Types of Food

• Food Type Diet Purpose Digestive End
  Product
• Fats lt30 Store energy Glycerol
  3 Absorb Vitamins fatty acids
• Protect
  organs
• Carbohydrates 55 Energy source
  monosaccharides Absorption of food
  glucose
• Fiber
• Proteins gt15 Growth Amino Acids
• maintenance/repair
• makes enzymes

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What happens to the Digestive End Product (listed
above)

• ? Absorbed into blood and delivered to cells and
  organs
• For Fats ? used or stored
• For Carbohydrates ?used for energy or stored
• For Proteins ?used to rebuild/enzymes
• Remember organisms are very efficiently adapted
  to providing the nutrients they need. The
  complex process of changing one type of
  macromolecule into another is very complex with
  any one able to change into the other, through
  many steps and much energy input.

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To speed Digestion organisms use chemicals and
enzymes

• Acids
• Gastric acid in stomach
• Contains HCl
• Bile
• Secreted by liver-stored in gall bladder
• Emulsifies fats (dissolves-NOT digest)
• Enzymes each enzyme (made of protein) is
  regulated, with a special job
• Jobs include
• Operate by Lock and Key approach
• Some examples
• Hydrolysis (Breaking down polysaccharides to
  create simple sugars)

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Enzymes are
1. Highly specific 2. Can speed up the same
chemical reaction in either
direction. 3. NOT used up in the reaction.
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Lipase is an enzyme that digests fat. Bile is a
solution that emulsifies fats. Together, they
speed up the breakdown of fats in the
digestive system.
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Enzymes in Plants

• Remember, Autotrophs make their own organic
  nutrients (simple sugars). How do plants do
  this?
• Enzymes speed the necessary chemical reactions
  and give organisms the ability to control how
  much, where, and when these reactions occur
  Glucose is coupled together into starch in the
  roots of plants for storage.
• The enzyme for this reaction is called Sucrase
• The chemical reaction that occurs is a
  Dehydration Synthesis, draw the structures of two
  glucose molecules being joined to create a
  disaccharide.

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How do they work?

• Enzymes function by binding to one or more of the
  reactants (substrate) in a reaction.
• The exact location on the enzyme where substrate
  binding takes place is called the active site of
  the enzyme.
• The shape of the active site just fits the shape
  of the substrate, somewhat like a lock fits a
  key.
• In this way only the correct substrate binds to
  the enzyme

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http//www.efhealing.com/images/enzymes.jpg
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Types of Enzymes

• Enzyme Made Here Acts
  Purpose
• Amylase Mouth Mouth
  breaks polysacs to
• Pancreas Sm. Intestine
  disacs (digests carbs)
• Pepsin Gastric glands Stomach
  Starts digestion
• of stomach
• Rennin Stomach Stomach
  Coagulates (thickens)
• protein in milk
• Lipase Pancreas Sm. Intestine
  Reduces fats to fatty
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  acids and glycerol
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  (building blocks of fats)

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Enzymatic Digestion of food types (Macromolecules)

• Name the chemical process used by these enzymes
  to help digest fats, carbohydrates, and proteins
• Use diagrams of Macromolecules to fill in the
  chart below. Use circled numbers to indicate
  locations of hydrolysis
• http//www.whfoods.com/genpage.php?tnamefaqdbid
  16digestion

Hydrolysis
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Digestive Problems

• Lactose Intolerence -
• Inability to digest milk sugar (enzyme lactase)
• Appendicitis -
• Bacteria gets in appendix and causes flu like
  symptoms and eventually shooting pain in right
  side. Surgically removed.

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• Tape worms
• Parasite that stays in your intestines and
  absorbs all the nutrients. Get it from
  undercooked meat.
• Diabetes
• Cannot produce insulin in pancreas