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Animal Nutrition
Human Digestion
AP Biology
2006-2007
What do animals need to live?
 Animals make __________
using:
__________________ food
 __________________

 Animals _______________
using:

__________________
 amino acids, sugars,
fats, nucleotides

ATP
__________________
Regents Biology
O2
__________________
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
Regents Biology
Getting & Using Food
 ________________

taking in food
 ________________

__________________________
 breaking up food into smaller pieces

__________________________
 breaking down food into molecules
small enough to be absorbed into cells
 enzymes
intracellular
digestion
 ________________

absorb across cell membrane
 ___________________
 ___________________
 ________________

undigested material passes out of body
Regents Biology
extracellular
digestion
Digestive systems
Everybody’s got one!
Regents Biology
Mouth
 Functions

_______________________
 _______________
 break up food

_______________________
 __________________________
 ____________________________
 mucus
 protects soft lining of digestive system
 lubricates food for easier swallowing
 buffers
 neutralizes acid to prevent tooth decay
 anti-bacterial chemicals
Regents Biology  kill bacteria that enter mouth with food
All that
in spit!
Swallowing (& not choking)
 ________________________



flap of cartilage
closes __________ (windpipe) when swallowing
food travels down _______________
 ________________________

involuntary muscle contractions to move food along
Regents Biology
Stomach
 Functions

______________________
 hydrochloric acid = pH 2
 kills bacteria

______________________
 can stretch to fit ~2L food

______________________
 _____________________
What stops the stomach from digesting itself?
mucus secreted by stomach cells protects
Regents Biology
stomach
lining
Ulcers
Colonized by
H. pylori
 Used to think
ulcers were
caused by stress

tried to control
with antacids
inflammation of
stomach
ulcers caused by
bacterial
infection of
stomach
inflammatory
proteins
(CagA)
cell damaging
proteins
(VacA)
 
H. pylori bacteria
 now cure with
antibiotics
Regents Biology
inflammation of
esophagus
H. pylori
 Now know

Free of
H. pylori
cytokines
helper T cells
neutrophil cells
white blood cells
Small intestine
 Functions

______________________
 _______________________
 amylase from pancreas
 _______________________
 trypsin & chymotrypsin from pancreas
 _______________________
 bile from liver & lipase from pancreas

______________________
 nutrients move into body cells by:
 diffusion
 active transport
Regents Biology
This is
where all the
work is done!
Absorption by Small Intestines
 ________________________________
finger-like projections
 _________________________________

SMALL INTESTINES
6 meters long,
but can stretch
to cover a
tennis court
Regents Biology
Pancreas
 _______________________________

__________________________
 trypsin, chymotrypsin

__________________________
 amylase

__________________________
 lipase
 Buffers
neutralizes
acid from
stomach
Regents Biology

small
intestine
pancreas
Liver & Gall Bladder
 ________________________
_________________________________
 _________________________________

 that’s why you can have your gall bladder
removed
bile contains
colors from old
red blood cells
collected in liver =
iron in RBC rusts &
Regentsfeces
Biology
makes
brown
Large intestines (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
 ____________________

Regents
 Biology
reabsorb
by diffusion
You’ve got company!
 Living in the large intestine is a
community of helpful bacteria

PEE-YOO!
Escherichia coli: ___________
 ____________________________
 digests fruits & vegetables
 ____________________________
 vitamin K & B vitamins
 ____________________________
 by-product of bacterial metabolism
 methane, hydrogen sulfide
 STINKY!
Regents Biology
Rectum
 Last section of large intestines
eliminate feces
 what’s left over?

 ___________________________
 mainly cellulose from plants
 called ___________________________
 keeps everything moving & cleans out
intestines
 masses of bacteria
Regents Biology
So don’t forget
to wash
your hands!
Different diets; different bodies
 Adaptations of herbivore vs. carnivore
teeth
 length of digestive system
 number & size of stomachs

Regents Biology
Teeth
 _______________
sharp ripping
teeth
 “canines”

 _______________
wide grinding
teeth
 molars

 _______________

both kinds of
teeth
Regents Biology
Length of digestive system
 Herbivores &
omnivores


long digestive
systems
harder to digest
cellulose (cell walls)
 bacteria in intestines
help
 Carnivores

short digestive
systems
Regents Biology
appendix
Eating a balanced diet
 What happens if an animal’s diet is
missing an essential nutrient?

deficiency diseases
 scurvy — vitamin C (collagen production)
 rickets — vitamin D (calcium absorption)
 blindness — vitamin A (retinol production)
 anemia — vitamin B12 (coenzyme function)
 kwashiorkor — protein
Regents Biology
Vegetarian diets
 Need to make sure you get enough protein

20 amino acids to make protein
 12 humans can make
 8 we have to eat = “essential amino acids”

Grains (like corn) have 6 amino acids
 missing 2

Beans (like soybean & red beans) have 6 amino acids
 missing different 2
 mix beans & grains
for complete group of
amino acids
 rice & beans
 taco/tortilla & beans
 tofu & rice
 peanut butter & bread
Regents Biology
Homeostasis
Blood Sugar
insulin
liver stores
body
_________
cells take
up sugar
_________
______________
high
reduces
________
liver
blood sugar level
low
triggers
_________
Regents Biology
liver
releases
_________
liver
______________
ucagon
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