Download Digestive and Excretory Systems

The Digestive System
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Section:
Section Outline
Section 38-1
38–1
Food and Nutrition
A. Food and Energy
B. Nutrients
1. Water
2. Carbohydrates
3. Fats
4. Proteins
5. Vitamins
6. Minerals
C. Nutrition and a Balanced Diet
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Section:
Food and Energy
•Cells convert the chemical energy stored in food into
ATP
•Food also supplies the raw materials used to build and
repair body tissues
– These raw materials are used to manufacture new
biomolecules
• Food also contains at least 45 substances that
your body cannot manufacture
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Section:
Concept Map
Section 38-1
Nutrients
include
Carbohydrates
Fats
Proteins
Vitamins
Minerals
include
are made of
are made using
include
include
Simple
Complex
such as
such as
Amino
acids
Fatty Acids
Sugars
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Section:
Starches
Calcium
Glycerol
Fat-soluble
Watersoluble
Iron
Carbohydrates
•Main source of energy for the body
– Can be simple
• found in honey, fruits, sugar cane
– Can be complex
• starches found in grains, potatoes, veggies
•Broken down to be absorbed into the blood
•If not used immediately, sugars can be stored in the liver and
muscles.
•Not all carbs can be broken down
– Fiber (roughage) keeps your digestive system functioning
properly by helping wastes to move through
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Section:
Fats (lipids)
•Needed to form cell membranes
•Extra food is stored as fat to protect body organs and
insulate the body
•Classified as saturated or unsaturated
– Saturated fats
• Solid at room temperature
• Main cause of high blood pressure, heart
disease, obesity and diabetes
– Unsaturated fats
• Liquid at room temperature
• A healthier choice of fat
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Section:
Proteins
•Supply raw materials for growth and repair of skin and
muscles
•Made from amino acids
•The body can only synthesize 12 of the 20 amino acids
– The other 8 must be ingested
• Found in meat, fish, milk, eggs
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Section:
Figure 38–8 Food Guide Pyramid
Section 38-1
Fats, Oils, and Sweets (use sparingly)
Soft drinks, candy, ice cream, mayonnaise, and
other foods in this group have relatively few
valuable nutrients.
Milk, Yogurt, and Cheese Group
(2-3 Servings)
Milk and other dairy products are rich in
proteins, carbohydrates, vitamins, and
minerals.
Vegetable Group
(3-5 servings)
Vegetables are a low-fat
source of carbohydrates,
fiber, vitamins, and minerals.
Fats
Sugars
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Section:
Meat, Poultry, Fish, Dry Beans, Eggs,
and Nut Group
(2-3 servings)
These foods are high in protein.
They also supply vitamins and minerals.
Fruit Group
(2-4 servings)
Fruits are good sources of
carbohydrates, fiber, vitamins
and water.
Bread, Cereal, Rice
and Pasta Group
(6-11 servings)
The foods at the base of the
pyramid are rich in complex
carbohydrates and also
provide proteins, fiber,
vitamins, and some
minerals.
Section Outline
Section 38-2
38–2
The Process of Digestion
A. The Mouth
1. Teeth
2. Saliva
B. The Esophagus
C. The Stomach
1. Chemical Digestion
2. Mechanical Digestion
D. The Small Intestine
Accessory Structures of Digestion
E. Absorption in the Small Intestine
F. The Large Intestine
G. Digestive System Disorders
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Section:
The Mouth
•Performs mechanical and chemical digestion
– Mechanical – food is changed in size
• Performed by the teeth
– Chemical – food is changed in composition
• Performed by saliva
– Contains amylase (an enzyme that breaks
down starch)
– Also helps to moisten food so it can move
easier
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Section:
The Esophagus
•Lined with smooth (involuntary) muscle
•Contractions, known as peristalsis, squeeze the food
through to the stomach
•A thick ring of muscle closes the esophagus after food
has entered the stomach to prevent the contents of the
stomach from moving back up.
– Is associated with heartburn
• A backflow of stomach acid into your
esophagus
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Section:
Stomach
•A large muscular sac
– Continues mechanical and chemical digestion
• Mechanical – churning
• Chemical – stomach glands release a variety of
secretions
– Any other chemical digestion is stopped until the
food reaches the small intestine
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Section:
Small Intestine (SI)
•Where digestion and then absorption occur
– Nutrients are absorbed into the bloodstream
•Water, cellulose and other undigestible substances
(like some fats) leave the SI and enter the large
intestine
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Section:
Accessory Organs
•Pancreas
– Produces enzymes that break down carbs,
proteins, lipids and nucleic acids
•Liver
– Produces bile which makes fat droplets small so
they can be broken down
•Gall Bladder
– Stores the bile that is produced by the liver
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Section:
Figure 38–13 The Liver and the Pancreas
Section 38-2
Liver
Bile duct
Gallbladder
Pancreas
Pancreatic duct
Duodenum
To rest of small intestine
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Section:
The Large Intestine (LI)
•Also known as the colon
•Primary function is to absorb water from undigested
materials
•The concentrated waste material that remains after the
water has been removed passes through the rectum,
where it is stored until it is eliminated from the body
through the anus.
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Section:
Figure 38–10 The Digestive System
Section 38-2
Mouth
Pharynx
Salivary glands
Esophagus
Liver
Gallbladder
(behind liver)
Stomach
Pancreas (behind
stomach)
Large intestine
Small intestine
Rectum
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Section:
Diseases of the Digestive System
Diarrhea
-frequent loose or liquid bowel movements
-If the large intestine does not reabsorb enough water, too much may
be eliminated from the body along with fecal matter.
-Upsets the body’s electrolyte balance unless fluids are replaced.
Constipation
- stools are usually hard, dry, small in size, and difficult to eliminate
- if the large intestine absorbs too much water, the fecal matter
becomes very hard and is unable to pass through the colon to the
rectum.
- treatment can include change in diet, more physical exercise and
laxatives
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Section:
The Excretory System
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Section:
Section Outline
Section 38-3
38–3
The Excretory System
A. Functions of the Excretory System
B. The Kidneys
1. Kidney Structure
2. Filtration
3. Reabsorption
4. Kidney Stones
C. Control of Kidney Function
D. Homeostasis by Machine
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Section:
Functions of the Excretory System
•Every cell in the body metabolic wastes as a result of
maintaining homeostasis
– Wastes must be removed from the body
•The skin, lungs and liver are three organs that assist in
excretion
– The skin excretes excess salts and water
– The lungs excrete carbon dioxide
– The liver takes excess amino acids from the blood
stream and converts them to useful compounds
• However, urea is created which must be
removed by the kidneys
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Section:
Kidneys
•The kidneys have many roles
– Remove waste products from the blood
– Maintain blood pH
– Regulate the water content of the blood and
therefore blood volume
•The kidney removes urea, excess water and other
wastes and passes them to the ureter
•The clean, filtered blood leaves the kidney and returns
to circulation
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Section:
Nephron
•The functional unit of the kidney
•Each nephron has its own blood supply
•Each nephron releases fluid into a collecting duct,
which leads to the ureters
•The ureters then lead to the bladder, where urine is
stored until it is excreted from the body by the urethra
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Section:
The Urinary System
Section 38-3
Vein
Kidney (Cross Section)
Kidney
Cortex
Medulla
Ureter
Urinary bladder
Urethra
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Section:
Artery
Disease
•Kidney Stones
– Salts in the urine crystallize and form stones
– These stones may block the ureter, causing great
pain
– Often treated using ultrasound waves
• The stones gets pulverized into smaller
fragments, which are then excreted in the urine.
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Section:
Homeostasis by Machine
•Dialysis
– Blood is removed from the body through a tube
and pumped through special tubing that acts like
nephrons
– Wastes diffuse out of the blood and into a fluidfilled chamber
– The purified blood is then returned to the body
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Section:
Figure 38–19 Kidney Dialysis
Section 38-3
Blood in tubing flows
through dialysis fluid
Blood pump
Vein
Artery
Used dialysis fluid
Shunt
Air detector
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Section:
Dialysis
machine
Fresh
dialysis
fluid
Compressed
air