Digestive System Vocab
Ingestion- the act of eating, this is the first stage
of food processing. Even the fluid feeders must
deal with food that is package. A package
contains very complex arrays of molecules. This
is called mechanical digestion.
Digestion- this is the second stage of food
processing. This is the process of breaking down
food into molecules small enough to absorb.
This is chemical digestion.
Enzymatic Hydrolysis- this is the process of
breaking bonds with the enzymatic addition of
water.
Absorption- this is the third stage of food
processing. In this stage the animal’s cells
absorb small molecules such as amino acids and
simple sugars from the digestive compartment.
Gastrovascular cavities- pouches/sacs with
single openings.They fuction in both digestion
and distribution of nutrients throughout the
body.
Ex. Hydras- carnivores that sting prey
with specialized organelles called nematocysts
and then use tentacles to stuff the food through
the mouth into the gastrovascular cavity.
Specialized Compartments of Digestion
-to avoid the body from digesting its
own cells and tissues.
Intercellular digestion
Food vacuoles are organelles in which
hydrolytic enzymes break down food without
digesting the cell’s own cytoplasm.
How? Newly formed food vacuoles fuse
with lysosomes which are organelles containing
hydrolytic enzymes and mix the food with the
enzymes allowing digestion to occur safely
within the compartment that is enclosed by a
protective membrane.
Who? This process is mostly done by
animals (this includes sponges) and
heterotrophic protest.
Extracellular Digestion
It has extracellular cavity for digestion to enable
an animal to devour much larger prey than can
be digested intracellularly.
How? They breakdown food outside the cell
Complete digestive tracts/ alimentary canals -
tubesextending from the mouth to the anus.
Moves food in one direction.
Food enters through the
mouth/pharynx and then passes through the
esophagus and that leads to the crop, gizzard,
or stomach (depending what we are talking
about)
Stomach and crop serve as food storage organs
(some digestion might occur there), gizzards
however, grind and fragment food.
The food enter the intestine, this is
where digestive enzymes hydrolyze the food
molecules, and nutrients are absorbed across
the lining of the tube and into the blood.
All undigested wastes are eliminated
through the anus.
Mammalian digestive system
Peristalsis- are rhythmic waves of contraction
by smooth muscles in the wall of the canal
Function: it pushes the food along the
tract.
Sphinceters- ring-like valves that close off the
tube like drawstrings.
Function: regulate the passage of
material between chambers of the canal.
Accessory glandsSaliva glands:
Pancreas:
Liver:
Gallbladder:
INITIATION OF FOOD PROCESSING
ORAL CAVITY
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