Transcript Chapter 11

Chapter 38
Digestive & Excretory System
Question of the day
 What is the first
part of food
digestion?
 Makes contact
with your mouth chewing!
38-1 Food & Nutrition
 Calories
 Nutrients - substances
that provide energy for
your body
 Kinds of Nutrients
 Water
 Carbohydrates - Sugar
 Fats - fatty acids
 Proteins - amino acids
 Vitamins - organics
 Minerals - inorganics
Vitamins
 Vitamins are the ignition of a
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body
Organic molecules work with
enzymes to regulate body
Important Vitamins:
A - retinol (green vegetables) for
sight & skin cells
B12 - cyanocobalamin (meat,
eggs, dairy) for red blood cells
C - ascorbic acid (citrus,
broccoli) for immune system
D - calciferol (fish oil, eggs) for
bone growth
Minerals
 Inorganic nutrients body
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needs in small amounts
Body does not digest
minerals, loses them
Important minerals
Calcium - dairy (bones)
Potassium - bananas
(nerves, acidity)
Sodium - salt (body water
balance)
Iron - meats, grains
(hemoglobin & ETC)
Zinc - meats, seafood
(digestion enzymes)
The Need to Balance a Diet
 Important to have
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each food group in
right proportions
5 necessary groups:
Dairy
Proteins
Veggies
Fruits
Grains
1 unnecessary group:
Fats, Oils, & Sweets
Question of the day
 What is the
technical term for
chewing your
food?
 Mastication
 Refers to your
muscles in the jaw
called masseters
38-2 Process of Digestion
 Digestion - converts foods into
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simpler molecules for use
Starts in the mouth with teeth chewing
Salivary glands kick in - secrete
enzymes to digest
Enzymes are called Amylase
break down sugar
Turns food into ball
Called BOLUS
Next Part of Digestion
 Once food is swallowed:
 Moves to PHARYNX (top
part of throat)
 Does NOT go into Larynx
 That’s your windpipe to
lungs
 Epiglottis prevents food &
water going to lungs
 Moves to ESOPHAGUS
 By PERISTALSIS - rythmic
contractions pushing
food to stomach
To the Stomach!
 How does food
enter?
 By a Sphincter
(Gateway)
 Stomach begins
digestion 2 ways
 Chemically
 Mechanically
Digestion (Cont.)
 Chemical  Hydrochloric Acid
 Mucus - protects stomach
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lining
Pepsin - break proteins
Mechanical Stomach muscles contract
& churn
Mix fluids & foods like
washing machine
Creates Chyme
Moving to Small Intestine
 Leaves stomach via
Pyloric Sphincter
 Into Small Intestine
 Gets help from
pancreas & liver
 Removes fats, proteins,
carbs thru wall
 Wall is made of VILLI
 Small fingers that
absorb all nutrients
Large Intestine
 Food is still Chyme
 Gets to Large Intestine
 Main goal is to remove
remaining nutrients &
water
 Then moves to colon as
waste
 Excreted thru rectum &
anal sphincter
 Called Stool (crap)
38-3 Excretory System
 Kidney - filters blood
 Starts in renal artery
 Goes to Nephron (1000s in
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a kidney)
There water, nutrients go
back to body
Wastes get filtered, sent to
ureter , bladder
What is waste called?
Urine
Cool Nephron
 Inside Nephron are three
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important parts:
Glomerulus - where artery
(blood) comes in
Bowman’s Capsule protects glomerulus
Loop of Henle - tube that
collects water, sends back
to body
Animals that are efficient
w/ water have very long
loops of Henle
Examples?
Camels
Other desert animals
Sea Birds
Kidney Problems & Diseases
 Two main problems that
effect Kidneys:
 Renal Failure (Dialysis) kidneys shut down and
unless something filters
blood - you die
 Diabetes - high blood
sugar makes kidneys
work very hard
 Body can’t absorb sugar
in blood