MCDB 1B- Digestion

-
ngestion FoodProcessing is
act of
eating
:




of down food into molecules
Digestion process breaking
small
enough to absorb
:




to
Mechanical
digestion chewing/grinding increase A.,
making digestion
:
·




S .
easier


-Chemical food small molecules that
digestion
:
splits into can
pass through membranes

Enzymatic hydrolysis Splits :
bonds in molecules
by adding
water



&



epithelial cells control what enters blood
fight junctions Keep epithelial cells joined
:


,




Absorption :
is
uptake of small molecules
by body
Elimination of material out of
undigested
·
:

passage
the
digestive system

, Nutrient Extraction


animals process food
specialized compartments
-



intestine in
large water intake
mostly
-these compartments reduce of
Small
most
intestines
nutrient
risk animal
digesting
here its own cells & issues
absorption
Protects tissues while B
body allowing acids
-




enzymes
to break down nutrients
Extracellular
Digestion
the breakdown of food particles outside of cells
·



It occurs in
compartments that are continuous w/ the

outside of the animal's
body

Digestive Systems astrointestinal
9of
tract


Alimentary Canal :

digestive tube w/z
openings ,
60 % cell types-epithelial tells

tract
Complete digestive



=> #




ofofficial
accessory glands are not
apart digestive tract, but secrete


digestive juices through ducts into the
alimentary canal

Mammalian
accessory glands are
·
the salivary glands 3 pair glands
:
secreted into mouth

the pancreas : lots of
enzymes B Secretionsl
·




for food
the liver : makes bile
digestion
·




into small intestine
- the
gallbladder : releases bile




Oral Cavity
-food oral cavity
processing begins in



salivary glands lubricate food
-Saliva contains mucus :
viscous mix of water salts
,
B glycoslyted
-




proteins also contains
amylase
Amylase in saliva breaks down starch
by hydrolyzing bonds between starch
-

:
,




-tongue movements shape food into a bolus (ball) to help swallow