PROCESS OF DIGESTION
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Transcript of PROCESS OF DIGESTION
PROCESS OF DIGESTION
Chapter 38-2Biology 392
Digestive System1. Function2. Structure3. Movement4. Processes
a. Digestioni. Mechanicalii. Chemical
b. Absorption5. Disorders
FUNCTIONBreaking down large food molecules into smaller nutrients.
INGESTIONDIGESTIONPERISTALSISABSORPTIONDEFECATION
STRUCTURE“FOOD TUBE”
• Mouth• Pharynx• Esophagus• Stomach• Small Intestine• Large Intestine
ACCESSORY ORGANS
• Teeth• Salivary Glands• Pancreas• Liver• Gall bladder
MOVEMENT• Mouth Moistens & tears food, results in
BOLUS “chewed clump of food”• Esophagus Bolus moves through tube by
PERISTALSIS rhythmic contractions• Sphincters tight rings of muscles that close
and open to separate the different organs– CARDIAC SPHINCTER
• Stomach after churning, food is liquefied = CHYME
– PYLORIC SPHINCTER
MOVEMENT (cont.)• Peristalsis movement through small intestine• Absorption through villi of small intestine into
blood stream nutrients travel everywhere!Go to all cells of body (brain is the priority) Proteins & Carbs go into blood Most fats go into lymphatic system
• Water is absorbed in large intestine• Undigested material passes through rectum • Leaves body through anus
PROCESS OF DIGESTIONMECHANICAL
• Physical change• Breaking food into smaller
parts by ripping, churning
• TEETH tear & crush• STOMACH churns
CHEMICAL
• Chemical change• Enzymes break bonds of
food molecules
• Enzymes are made and used by organs– Not always the same
• Each enzyme is specific to a type of macromolecule– Carb, fat or protein
Where does Digestion occur?What Nutrient is Digested?ORGAN TYPE OF DIGESTION NUTRIENT DIGESTED
MouthMechanical
Chemical
All
Carbohydrates
StomachMechanical
Chemical
All
Protein
Small Intestine Chemical All
ENZYMES OF DIGESTION
ENZYME SITE OF ACTION SITE of PRODUCTION NUTRIENT DIGESTED
Amylase
Pepsin
Lipase
Amylase
Trypsin
Peptidase
Maltase
Sucrase
Lactase
Mouth
Stomach
Small intestine
Small intestine
Small intestine
Small intestine
Small intestine
Small intestine
Small intestine
Salivary glands
Lining of stomach
Pancreas
Pancreas
Pancreas
Lining of small intestine
Lining of small intestine
Lining of small intestine
Lining of small intestine
Carbohydrate
Protein
Fat
Carbohydrate
Protein
Carbohydrate
Carbohydrate
Protein
Carbohydrate
OTHER SUBSTANCES INVOVLED IN DIGESTIONSUBSTANCE SITE OF ACTION ACTION
Saliva Mouth Moistens Food
MucusEsophagus, Stomach
Sm. & Lg. Intestines
Helps food move easily
Protects organs
Hydrochloric Acid (HCl) Stomach Helps breakdown food
Kills bacteria
Sodium bicarbonateSmall Intestine
(made in pancreas)
Neutralizes acid so
enzymes can function
BileSmall intestine
(made in liver,
stored in gall bladder)
Separates fat droplets,
making them easier to
break down.
Bacteria Large IntestineHelp breakdown food
Produce vitamin K
ABSORPTION
• After Polymers are broken into Monomers, they must “enter” the body & be circulated.
• Absorbed across the cell membranes of each cell lining the small intestine
• Surface area of S.I. is increased by folds– Villi and microvilli
ABSORPTION cont.
• Water is also absorbed• Occurs across the wall of the Large Intestine
• All that is left is concentrated waste– Undigested material– Cellulose, fiber
ELIMINATION
• Undigested moves through large intestine and is held in rectum until it is eliminated
DISORDERS• Heartburn stomach acid enters esophagus
because of weak cardiac sphincter• Peptic Ulcer Hole in stomach wall caused by
Helicobacter pylori. The pain is caused by the acid.
• Diarrhea Not enough water is absorbed• Constipation Too much water is absorbed• Diabetes Glucose cannot enter cells of body
very well, therefore glucose cannot get turned into energy!!
Diabetes• 6th killer in America (and rising)• Pancreas cannot produce insulin or the body
does not use it properly• Insulin is a hormone that decreases the
amount of sugar in the blood by helping it enter the cells of the body.– Glucose does not enter cells easily, insulin must
“act like a butler” and bind to a cell membrane protein to help it in.
SUMMARY QUESTIONS
• What are the 2 types of digestion?• Where does digestion begin?• Where does MOST digestion happen?• Where do nutrients enter the rest the of the
body? (i.e. leave the GI tract)