Topic 8
Animal Nutrition / Human Digestion
What do animals need to live?
• Animals make energy using:
– __________
– __________
• Animals build bodies using:
– ____________________________________________
• amino acids, sugars, fats, nucleotides
– ____________________________________________
How do animals get their food?
 __________________________
 __________________________
 __________________________
 __________________________
Different diets; Different lives
• All animals eat other organisms
– ________________________
• eat mainly _____________
– gorillas, cows, rabbits, snails
– ________________________
• eat other _______________
– sharks, hawks, spiders, snakes
– ________________________
• eat _______________________________
– cockroaches, bears, raccoons, humans
– humans evolved as hunters, scavengers &
gatherers
Getting & Using Food
• ________________
– taking in food
• ________________
– ____________________________
• ______________________________________________
– ____________________________
• ______________________________________________
______________________________________________
• __________________
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• _______________
– absorb nutrients across cell membranes
• _____________________________
• _____________________________
• _______________
– undigested material passes out of body
Human Digestive System
Mouth
• Functions
– ______________________________
• _________
– break up food
– ______________________________
• amylase enzyme
– _____________________
• _____________
– protects soft lining of digestive system
– lubricates food for easier swallowing
• _____________
– neutralizes acid to prevent tooth decay
2
• ________________________________
– kill bacteria that enter mouth with food
Swallowing (& not choking)
• ____________________
– flap of cartilage
– closes ____________ (windpipe) when swallowing
– food travels down _________________
• ______________________
– involuntary muscle contractions to move food along
Stomach
• Functions
– ______________________________
• hydrochloric acid = pH 2
– kills bacteria
– ______________________________
• can stretch to fit ~2L food
– ______________________________
• _________________________
But the stomach is made out of protein!
What stops the stomach from digesting itself?
___________________________________________
___________________________________________
Ulcers
• Used to think ulcers were caused by stress
– tried to control with antacids
• Now know ulcers caused by bacterial infection of stomach
– __________________ bacteria
– now cure with antibiotics
Small Intestine
• Functions
– _________________________
• ____________________________________
– amylase from pancreas
• ____________________________________
– trypsin & chymotrypsin from pancreas
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• _____________________________________
– bile from liver & lipase from pancreas
– ______________________
• nutrients move into body cells by:
– ___________________________
– ___________________________
Absorption in Small Intestines
• Absorption through ____________________________________
– finger-like projections
– ____________________________________ for absorption
Pancreas
• Produces digestive enzymes
– digest ______________
• trypsin, chymotrypsin
– digest ______________
• amylase
– digest ______________
• lipase
• Buffers
– _____________________________ from stomach
Liver & Gall Bladder
• _______________________________
– __________________________
– gallbladder only ____________________________
• that’s why you can have your gall bladder removed
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Bile contains colors from old red blood cells collected in liver =
iron in RBC rusts & makes feces brown
Large Intestine (colon)
• Function
– ____________________________________
• use ~9 liters of water every day in
digestive juices
– if don’t reabsorb water would die
of dehydration
• > 90% of water re-absorbed
– not enough water re-absorbed
» __________________
» can be fatal!
– too much water re-absorbed
» __________________
• reabsorb by diffusion
You’ve got company!
• Living in the large intestine is a community of helpful bacteria
– Escherichia coli: ________________
• ______________________________
– digests fruits & vegetables
• ______________________________
– vitamin K & B vitamins
• ______________________________
– by-product of bacterial metabolism
– methane, hydrogen sulfide
Appendix
Rectum
• Last section of large intestine
– ________________________________________
– what’s left over?
• ___________________________________
– mainly cellulose from plants
– called _________________________________
– keeps everything moving & cleans out intestines
• masses of bacteria
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_______
______________
______________
______________
______________
__________
_______________
_______________
_______________
_______________
_________
____________________
- __________________
____________________
__________________
__________________
- ________________
- ________________
- ________________
__________________
_____________
_____________________
_____________________
_______________
_______________
__________
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Different diets; Different bodies
• Adaptations of herbivore vs. carnivore
– _________________________
– ___________________________________________________
– ___________________________________________________
Teeth
• _____________________
– sharp ripping teeth
– “canines”
• _____________________
– wide grinding teeth
– molars
• _____________________
– both kinds of teeth
Length of Digestive System
• Herbivores & omnivores
– ________ digestive systems
– harder to digest cellulose (__________________)
• bacteria in intestines help
• Carnivores
– ___________ digestive systems
– protein easier to digest than cellulose
Eating a balanced diet
• What happens if an animal’s diet is missing an essential nutrient?
– deficiency diseases
• ___________— vitamin C (collagen production)
• ___________ — vitamin D (calcium absorption)
• ___________ — vitamin A (retinol production)
• ___________— vitamin B12 (energy production)
• kwashiorkor — protein
Vegetarian diets
• Need to make sure you get enough ________________
– ___________________________________________________
• 12 amino acids humans can produce
• 8 we have to eat = “essential amino acids”
– Grains (like corn) have 6 amino acids
• missing 2
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– Beans (like soybean & red beans) have 6 amino acids
• missing different 2
• mix beans & grains for complete group of amino acids
– _________________________________
– _________________________________
– _________________________________
– _________________________________
Homeostasis - Balancing Blood Sugar levels
pancreas
insulin
glucagon pancreas
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