Regents Biology Digestive System Midterm Content
Jan 04, 2016
Regents Biology
Digestive SystemMidterm Content
Human digestive system
Mouth
Teeth - mechanical digestion break up food
Saliva - chemical digestion amylase enzyme digests starch
All thatin spit
Esophagus –Swallowing (& not choking)
Epiglottis flap of cartilage closes trachea (windpipe) when swallowing food travels down esophagus
Peristalsis
involuntary muscle contractions to move food along
Small intestine Functions
digestion digest carbohydrates
amylase from pancreas
digest proteins trypsin & chymotrypsin from pancreas
digest lipids (fats) bile from liver & lipase from pancreas
absorption nutrients move into body cells by:
diffusionactive transport
Absorption in Small Intestines Nutrient absorption through villi
finger-like projections increases surface area for absorption
SMALL INTESTINES6 meters long,but can stretch
to cover a tennis court
Liver & Gall Bladder Produces bile
breaks up fats gallbladder only stores bile
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 & makes feces brown
bile contains colors from old red blood cells collected in liver =iron in RBC rusts & makes feces brown
Function re-absorbs water
not enough water re-absorbed Diarrhea
too much water re-absorbed constipation
Large intestines (colon)
Rectum Last section of large intestines
eliminate feces what’s left over?
undigested materials mainly cellulose from plants called roughage or fiber keeps everything moving & cleans out
intestines
masses of bacteria
You’ve got company! Living in the large intestine is a
community of helpful bacteria Escherichia coli: E. coli
Help digest cellulose digests fruits & vegetables
produce vitamins vitamin K & B vitamins
BUT generate gases by-product of bacterial metabolism methane, hydrogen sulfide STINKY!
stomachkills germs break up fooddigest proteinsstore food
mouthbreak up fooddigest starchkill germsmoisten food
small intestinesbreakdown food
- proteins- starch- fats
absorb nutrients
pancreasproduces enzymes to digest proteins & carbs
liverproduces bile
- stored in gall bladderbreak up fats
large intestinesabsorb water
Trivia 1
The function of the digestive system is to . . .
a.chemically break down food
b.absorb nutrient materials
c.mechanically break apart food
d.all of the above
Trivia 2
The villi of the small intestine allow for an increase in the rate of . . .
a.nutrient absorption
b.acid production
c.cellulose digestion
d.bile production
Trivia 3
Enzymes in saliva begin the chemical digestion of . . .
a.fat
b.Protein
c.carbohydrates
d.vitamins
Trivia 4
Where does protein digestion start in the human body?
a.the mouth
b. the stomach
c. the small intestine
d.large intestine
Trivia 5
The main function of the large intestine is to:
a.store waste
b.absorb water from digested food
c.digest proteins
d.none of the above