Transcript AP Biology Swallowing

Animal Nutrition
AP Biology
2006-2007
What do animals need to live?
 Animals make energy
using:
food
 oxygen

food
 Animals build bodies
using:

food for raw materials
 amino acids, sugars,
ATP
O2
fats, nucleotides

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ATP energy for synthesis
How do animals get their food?
filter (suspension) feeding
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fluid feeding
substrate feeding
bulk feeding
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Getting & Using Food
 Ingest

taking in food
 Digest

mechanical digestion
 breaking up food into smaller pieces

chemical digestion
 breaking down food into molecules
small enough to be absorbed into cells
 enzymes (hydrolysis)
intracellular
digestion
 Absorb

absorb across cell membrane
 diffusion
 active transport
 Eliminate

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undigested extracellular material
passes out of digestive system
extracellular
digestion
Digestive systems
Everybody’s got one!
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Human digestive system
Alimentary Canal
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Common processes & structures
 Movement & Control

peristalsis
 push food along by rhythmic waves of
smooth muscle contraction in walls of
digestive system

sphincters
 muscular ring-like valves, regulate the
passage of material between sections of
digestive system
 Accessory glands

salivary glands, pancreas, liver & gall
bladder
 secrete digestive juices (enzymes & fluid)
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 http://www.neok12.com/php/watch.php
?v=zX500a066365600175060063&t=Dige
stive-System
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Swallowing (& not choking)
 Epiglottis




problem: breathe & swallow through same orifice
flap of cartilage
closes trachea (windpipe) when swallowing
food travels down esophagus
 Esophagus
move
APBiology
food along to stomach by peristalsis
Ingestion
 Mouth

mechanical digestion
 teeth
 breaking up food

chemical digestion
 saliva
 amylase
enzyme digests starch
 mucin
 slippery protein (mucus)
 protects soft lining of digestive system
 lubricates food for easier swallowing
 buffers
 neutralizes acid to prevent tooth decay
 anti-bacterial chemicals
 kill bacteria that enter mouth with food

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mouth
break up food
moisten food
digest starch
kill germs
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Stomach
 Functions

food storage
 can stretch to fit ~2L food

disinfect food
 HCl = pH 2
 kills bacteria
 breaks apart cells

chemical digestion
 pepsin
 enzyme breaks down proteins
 secreted as pepsinogen
 activated by HCl
But the stomach is made out of protein!
What stops the stomach from digesting itself?
mucus secreted by stomach cells protects
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stomach lining
Ooooooh!
Zymogen!
mouth
break up food
moisten food
digest starch
kill germs
stomach
kills germs
store food
break up food
digest proteins
cardiac
sphincter
pyloric
sphincter
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Coevolution of parasite & host
Ulcers
Colonized by
H. pylori
 Used to think
ulcers were
caused by stress

tried to control
with antacids
inflammation of
stomach
Helicobacter pylori
 now cure with
antibiotics

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inflammation of
esophagus
H. pylori
 Now know ulcers
caused by
bacterial
infection of
stomach
Free of
H. pylori
inflammatory
proteins
(CagA)
cytokines
cell damaging
proteins
(VacA)
helper T cells
neutrophil cells
white blood cells
Small intestine
 Function


major organ of digestion & absorption
chemical digestion
 digestive enzymes

absorption through lining
 over 6 meters!
 small intestine has huge surface area = 300m2 (~size
of tennis court)
 Structure

3 sections
 duodenum = most digestion
 jejunum = absorption of nutrients & water
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 ileum = absorption of nutrients & water
Duodenum
 1st section of small intestines

acid food from stomach mixes with
digestive juices from accessory glands:
 pancreas
 liver
 gall bladder
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Pancreas
 Digestive enzymes

What stops
Ooooooh!
pancreas
Zymogen!
from
digesting
itself
peptidases
 trypsin
 trypsinogen
 chymotrypsin
 chimotrypsinogen
 carboxypeptidase
 procarboxypeptidase

small intestines
pancreatic amylase
 Buffers

reduces acidity
 alkaline solution rich in
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bicarbonate (HCO3-)
 buffers acidity of material from
stomach
Explain how this is a
molecular example of
structure-function theme.
mouth
break up food
moisten food
digest starch
kill germs
pancreas
produces enzymes to
digest proteins & starch
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stomach
kills germs
break up food
digest proteins
store food
Liver
 Digestive System Functions

produces bile
 stored in gallbladder until needed
 breaks up fats
 act like detergents to breakup fats
Circulatory System
Connection
bile contains
colors from old
red blood cells
collected in liver =
iron in RBC rusts &
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makes
feces brown
mouth
break up food
moisten food
digest starch
kill germs
liver
produces bile
- stored in gall bladder
break up fats
pancreas
produces enzymes to
digest proteins & starch
AP Biology
stomach
kills germs
break up food
digest proteins
store food
 The Liver and Pancreas - YouTube
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 Digestion 2 - YouTube
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Absorption by Small Intestines
 Absorption through villi & microvilli

finger-like projections
 increase surface area for absorption
Ooooh…
Structure-Function
theme!
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Absorption of Nutrients
 Passive transport

fructose
 Active (protein pumps) transport

pump amino acids, vitamins & glucose
 against concentration gradients across
intestinal cell membranes
 allows intestine to absorb much higher
proportion of nutrients in the intestine than
would be possible with passive diffusion
 worth the cost of ATP!
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nutrients are valuable…
grab all you can get!
 Small Intestine - YouTube
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mouth
break up food
moisten food
digest starch
kill germs
liver
produces bile
- stored in gall bladder
break up fats
pancreas
produces enzymes to
digest proteins & starch
AP Biology
stomach
kills germs
break up food
digest proteins
store food
small intestines
breakdown all foods
- proteins
- starch
- fats
- nucleic acids
absorb nutrients
Large intestines (colon)
 Function

re-absorb water
 use ~9 liters of water every
day in digestive juices
 > 90% of water reabsorbed
 not enough water absorbed
back to body
 diarrhea
 too much water absorbed back to body
 Constipation
 http://www.youtube.com/watch?NR=1&
v=cdijh32NiLs&feature=fvwp
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You’ve got
company!
Flora of large intestines
 Living in the large intestine is a rich
flora of harmless, helpful bacteria

Escherichia coli (E. coli)
 a favorite research organism

bacteria produce vitamins
 vitamin K; biotin, folic acid & other B vitamins

generate gases
 by-product of bacterial
metabolism
 methane, hydrogen sulfide
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Rectum
 Last section of colon (large intestines)

eliminate feces
 undigested materials
 extracellular waste
Tell them
about the rabbits,
 mainly cellulose from plants
George!
 roughage or fiber
 salts
 masses of
bacteria
appendix
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 Poop Primer | The Dr. Oz Show
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mouth
break up food
moisten food
digest starch
kill germs
liver
produces bile
- stored in gall bladder
break up fats
pancreas
produces enzymes to
digest proteins & carbs
AP Biology
stomach
kills germs
break up food
digest proteins
store food
small intestines
breakdown food
- proteins
- starch
- fats
absorb nutrients
large intestines
absorb water
Problems of the Digestive System: (P. 368)
 ulcer: a hole or sore inside the stomach or small
intestine often caused by H-Pylori bacteria
 Our stomachs are covered by mucus which protects the
lining.
 heartburn: is when stomach acids move up the
esophagus. We call it "heartburn" but it is from the
esophagus which is behind the heart. Eating too
much or irritating foods can cause heartburn. (Also
called G.E.R.D)
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Digestive Disorders Continued!
 Celiac- cannot tolerate the protein gluten (wheat, rye,
and barley), and the immune system responds by damaging
the villi in the small intestine and interferes with absorption
of nutrients from food.
 http://www.youtube.com/watch?v=EmZczwtsbVc
 Constipation -
too much water is removed from
waste resulting in stools that are too hard and difficult to
excrete (Increase fiber in diet and get enough fluids to
prevent this )
 Choking - food is trapped in windpipe (failure of
epiglottis to close the airway when swallowening)
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Lactose Intolerance
 Is the inability to digest a lot of lactose

(sugar found in milk).
Caused by a shortage of the enzyme
lactase
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Salmonella
 Salmonella - Bacteria found on raw
chicken and eggs...undercooked meat
can cause salmonella poisening which
can lead to death
 Ecoli - Bacteria that live in the
intestinal tracks of animals and birds
and is transmitted to humans when we
eat food that is contaminated with
animal feces.
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Colitis
 Is a disease involving the inflammation

of the colon or other parts of the large
intestine.
Chrons disease is a type of
inflammatory colitis. It is a chronic
inflammatory disease affecting mostly
the small and large intestine.

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Occurs when the body’s immune
system, attack your body’s own tissues
Appendicitis
 appendix becomes blocked with mucus
causing the bacteria that usually lives
in your appendix to become infected
and then multiply resulting in
inflammation.
AP Biology
Conditions of the digestive system!
 Pathology of Crohn's disease –
YouTube
 Lactose Intolerance | Signs and
Symptoms | Video | Veria Living YouTube
 Celiac Disease – YouTube
 http://www.youtube.com/watch?v=y8Od
jZIw6fA
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 http://www.youtube.com/watch?v=FCF
hvE5FVFU
 http://www.youtube.com/watch?v=uKU
SGOB-0V8
 http://www.youtube.com/watch?v=V4OI
L4bkoJ8
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 -When you lack certain vitamins it can cause diseases:
 Lack of vitamin A loss of night vision where too much can cause hair
loss.
 Lack of vitamin C can cause scurvy (P. 189 table 9-1)
 Do You Know Your Superfoods? | The Dr. Oz Show
 RDA: Recommended daily allowance
 %DV: Percent daily value. It is the amount (%) of nutrient found
compared to 100% which you need everyday.

If you have eaten food with Vitamin A 85%...then you still need to
eat food that contains another 15% to get recommended amount.
 How to Read a Food Label - Video - Oprah.com
AP Biology
 http://www.hc-sc.gc.ca/fn-an/labeletiquet/nutrition/cons/interactiveeng.php
 The Nutrition Facts Table - Consumers Nutrition Labelling - Health Canada
 Estimate How Long You Will Live:
Lifespan Calculator | The Dr. Oz Show
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Healthy Eating!
 Healthy Eating: What to Put on Your
Plate - Watch WebMD Video
 Healthiest Foods at the Supermarket Watch WebMD Video
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 Food Additives Effects on Kids - Watch
WebMD Video
 http://www.youtube.com/watch?v=n1pC
yUZW8ys&feature=related
 http://www.youtube.com/watch?v=4ZP
RNTjrrbY&feature=related
AP Biology
 Go to www.neok12.com for quizes and
videos….
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