Transcript Human Digestion

UNIT 14: NUTRITION & DIGESTION
CH. 9 & CH. 10
•In
the first unit we talked about
the characteristics of life….
•Which one(s) relates to this unit?
How do organisms get that energy?
•
How do organisms get food?
•
•What
do they do to food so that the
nutrients can get into their cell(s)?
•What about multicellular organisms??? How do
nutrients get to all of their cells?
NUTRIENTS
 What

are nutrients?
complex & simple substances required for life processes
 What
must be done to large molecules (carbs, fats,
& proteins) that doesn’t need to be done small
molecules (water, vitamins, & minerals)? Why?

large molecules need to be digested (broken down) so
that they can diffuse through cell membranes
•Are undigestable materials
considered nutrients?
•Why is water important?
WHAT IS DIGESTION?

What is digestion?

breakdown of complex
organic molecules into
simple molecules


Why is this necessary?


polymers 
monomers/building blocks
Monomer
(building blocks)
Function
Carbohydrates
(sugars,
starches,
cellulose)
polysaccharide
(such as starch
& cellulose)
monosaccharide
(simple sugars
such as glucose)
Energy source,
energy
reserve, plant
cell walls
Lipids
(fats, oils, &
waxes)
Not applicable
Fatty acids &
Glycerol
(Built from 2
types of simpler
molecules… NOT
monomers.)
Energy
reserves, cell
membrane,
hormones,
insulation,
nerve
transmission
Protein
Polypeptides
Amino acids
(20 different A.A.)
Structure,
enzymes,
transport
materials in &
out of cells
hormones,
muscle
Nucleic Acids
(DNA & RNA)
Polynucleotide
(Nucleic Acids)
Nucleotides
(sugar-phosphate
backbone &
nitrogenous
bases)
Carries genetic
code
(“blueprint for
organism) &
directs protein
synthesis
mechanical (ex. chewing)

Why is this necessary?


Polymer
so molecules can diffuse
through cell membranes
2 types of digestion?

Organic
Biological
Macromolecule
to increase surface area &
make chemical digestion faster
chemical

involves enzymes
HUMAN NUTRITION & DIGESTION
 Examples
of complex
nutrients?



proteins
fats (lipids)
carbohydrates
 Do
complex nutrients
require digestion?
Why/why not?

Yes, b/c too big to
diffuse through cell
membrane.
 Examples
of simple
nutrients?



vitamins
minerals
water
 Do
simple nutrients
require digestion?
Why/why not?

No, b/c small enough to
diffuse through cell
membrane
HUMAN DIGESTIVE
SYSTEM
Human Digestion
 What
type of digestion
takes place in the mouth?

physical

chewing


chemical


Why do we chew food?
 increases surface area &
speeds up chemical digestion
enzymes (starches  sugars)
What does saliva do?
moistens food
 contains enzymes

enzyme (salivary amylase)
starch
(polysaccharide )
maltose sugar
(disaccharide)
Human Digestion
 What

connect mouth to stomach
 How

do the pharynx & esophagus do?
is food moved?
peristalsis

alternating contraction & relaxation of smooth
muscle move food to stomach
Human Digestion
 What
•
is the epiglottis?
flap of tissue that protects trachea (windpipe) while
swallowing
peristalsis
Human Digestion
 What happens in the stomach?

physical digestion

How?


churning
chemical digestion

of protein into polypeptides begins

How?


gastric juices made of enzyme (pepsin)
& hydrochloric acid
rugae
storage

stomach slowly releases
chyme into small intestine
•What is the function of rugae?
•Why doesn’t your stomach digest itself???
Human Digestion
 accessory

What does the pancreas do?


secretes pancreatic fluid containing
enzymes into the small intestine
What does the liver do?

produces bile


organs
breaks fats into tiny drops
What does the
gall bladder do?

stores bile
Does food actually go
through these
accessory organs?
How is structure related
to function in the
digestive system?
Human Digestion
 What
happens in the small
intestine?

pancreatic enzymes & bile are
added to chyme


digestion of starches, proteins, &
fats is completed
nutrients absorbed thru walls
of villi into bloodstream

What do villi “add” to the small
intestine?/Why is this important?

add surface area which increases the
efficiency of absorption of nutrients
Human Digestion
What
does the
large intestine
(colon) do?
 reabsorbs water
& salts
 forms solid feces
Where is feces
stored?


rectum
Which part is
used to eliminate
feces?


anus
anus
Let’s See What You Remember…
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Let’s See What
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