digestion ppt. 2 revised regents
TRANSCRIPT
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Do Now: Label the Human Digestive
system
Digestive System:Answers
Aim: The Digestive System
1. Mouth
2. Esophagus
3. Stomach
� Nutrition: the process by which organisms
get food and break it down so it can be used for metabolism.
� Nutrients: substances in food that supply
energy for growth, repair, and maintenance.
Digestive System
Nutrients
6 Main
Nutrients
water
carbohydrates
fat
Proteins
vitamins
minerals
� Water
- essential for all body processes
- temperature regulation
� Carbohydrates
- main energy source
� Fats
- stores energy
- insulation
- needed for making hormones
� Proteins
- growth & repair
- regulation & transport
� Vitamins
- organic molecules to regulate body processes
� Minerals
- inorganic nutrients for making teeth, bones, & hemoglobin
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Digestion: the process of converting food into
forms that can be absorbed and used by the
body.
2 Types of
Digestion
Mechanical Chemical
Mouth
Functions:
1. Mechanical Digestion� Breaking, crushing, or mashing
down food by chewing.
� Food mixes with saliva.
2. Chemical Digestion� Enzymes break down food from large molecules into
nutrients.
� Starch begins to breakdown.
Specialized Structures & Their Functions
1. Teeth
� Break foods down into
smaller pieces.
2. Tongue
� Moves food around the mouth and to the back of the throat for swallowing.
Starch
-a polysaccharide into a disaccharide
What Part(s) of Food is Digested
In The Mouth?
Esophagus
Function:
� Muscular tube that transports
food from mouth to stomach.
What is peristalsis?
� muscular contractions that move food through the tube (involuntary)
http://www.mennellmedia.co.uk/VideoProjects/Peristalsis/Peristalsis.html
Stomach(Collection, Some Digestion)
Functions:1. Storage of food
2. Mechanical break down of food
� Mixes up food and digestive juices through muscle action to make chyme.
� Chyme- a thin soupy liquid in the stomach.
3. Chemical Digestion� Begins when digestive juices (containing HCl & pepsin) break down
chyme.
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What Part(s) of Food Gets Digested
In The Stomach?
� Proteins
Protease enzymes break down proteins into amino acids
http://www.bbc.co.uk/schools/ks3bitesize/science/biology/diet_4.shtml
Stomach
Small Intestine
Functions:
1. Chemical Digestion
- completed here.
2. Absorption of nutrients
(carbohydrates, proteins, &
lipids)
Small intestine absorbs……
�Carbohydrates
�Proteins
�Fats
What Part of Food Gets Digested?
� Proteins
� Polysaccharides
� Disaccharides
� Fats
� Starch
What Part of Food Gets Digested?
� Proteins Amino acids
� Polysaccharides Disaccharides
� Disaccharides Simple sugars
� Fats Fatty acid & Glycerol
� Starch Glucose
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Specialized Structures
1. Villi
� Fingerlike projections
� Folds in the lining that increase
the surface area for Absorption.
2.Lacteals absorb Fatty acids and
glycerol and send it to the lymph vessels.
3. Blood Capillaries absorb Sugars and
Amino Acids absorb and send to
bloodstream.
How Do Substances Get Absorbed
Into The Blood Stream?
1. Diffusion
2. Active Transport
http://www.uclan.ac.uk/facs/health/nursing/sonic/scenarios/uclananim/wholebodyzoom.swf
Large Intestine
3 Main
Functions
Reabsorption
of water and
salts from fecal
material Absorption
of vitamins
produced by
bacteria
Elimination of
undigested &
indigestible
material
Included: the appendix, colon, sigmoid colon, rectum, and anal canal.
What Parts of Food Gets Digested
In The Large Intestine?
None
Large Intestine
� E. coli bacteria living here produce vitamin
K (which is involved in blood clotting) through
fermentation.
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Rectum
� The end of the large intestine.
� Stores wastes
� Waste products move into colon and remain
there for a day or two until wastes leave body (defecation) through the anus.
Accessory Organs
Salivary Glands
Gastric Glands
Pancreas
Liver
Gall bladder
Salivary Glands
Site of action: Mouth
Functions:
1. Secrete saliva to wet food
2. Secrete salivary amylase to break downstarch
Gastric Glands
Site of action: Stomach
Functions:
1. Secretes juice to bring the pH to
approximately 2
2. Secretes pepsin (enzyme) to breakdown
proteins
Pancreas
Secretes powerful pancreatic enzymes:amylase, proteases, lipase
These enzymes break down complexcarbohydrates, proteins, and fats
Site of action: Small Intestine
Function:
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Liver
1. Produces bile - breaks down fats into droplets
(emulsification: mechanically breaks down large drops into smaller drops)
Site of action: Small Intestine
Function:
Gall bladder
1. Stores bile
** Bile travels from gall bladder to small intestine through the bile duct.
Site of action: Small Intestine
Function:
Medical Conditions
Or
Disruptions
Heartburn
� What is heartburn?
ACID from the stomach backs up into the
esophagus
Ulcers� What is an ulcer?
Erosion of the surface of the inner canal generally associated with some kind of irritant.
Causes: HCL acid, H. Pylori (bacterium), chronic use of aspirin, cigarette smoking
S/S: Burning
Treatment: antibiotics,
medication
http://www.walgreens.com/adamHtml/animation/200000.htm;jsessionid=F77AA8F4DBB3057F15A17EB32BA69F8B.b_00
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Diarrhea
� What is diarrhea?
Gastrointestinal disturbance characterized by decreased water absorption and increased peristaltic activity of the large intestine
Results in increased, watery feces and dehydration
Constipation
� A condition in which large intestine is
emptied with difficulty
� WHY?
Because too much water is
reabsorbed and solid waste hardens
Gallstones� What is Gallstones?
Gallstones is an accumulation of hardened cholesteroldeposits in the gallbladder and/or bile duct
S/S: pain, yellow jaundice (skin turns yellow)
Diagnosis: ultrasound (sonography)
Treatment: Can either be passed (OUCH!!) or surgically removed
Pancreatitis
� What is pancreatitis?
•Pancreas disease. Occurs when the pancreas
becomes quickly and severely inflamed.
•Causes: Heavy alcohol ingestion, Unknown
factors
•S/S: severe pain
•Treatment: IV treatment, no food intake
Hookworm
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Tapeworm
THE END