Download All About the Little Fish

Respiratory System:
Purpose:
- exchange O2 and CO2 between an
organism and its environment
-fish use their mouths to breath and not
nostrils.
Respiration:
-Occurs in a fish’s gills
-gills are located on the sides of
a fish’s head
• Gills have a large surface area
which allow for rapid exchange of
oxygen and carbon dioxide
• Each gill is composed of 4 gill arches
-a gill arch is a curved, cartilaginous
bone
-on the outside of each arch is a double
row of thin projections called gill
filaments.
Gill filaments are feathery
structures which increase the
surface area of the gill for gas
exchange.
Each filament contains many blood
vessels
Gill arches also have gill rakers
-located on the inside of the gill
arch.
-rakes out or filters out food,
preventing food from entering
the gills.
Water enters the mouth and is pumped over
the gills.
Water flows over the filaments which are
loaded with blood vessels.
The dissolved oxygen from
the water diffuses into the
blood.
Blood transports oxygen
to the cells.
Cells take in oxygen and release carbon
dioxide as a waste.
Carbon dioxide enters blood and is
transported back to the gills where it is
released into the water
The operculum
covers the gills.
Excretory System:
Purpose: to remove nitrogenous
waste (ammonia) from the blood
which is created by the cells going
through metabolism
Kidney
Urogenital opening
1. Blood containing ammonia can pass
through the gills and be excreted out
into the water.
OR
2. A fish’s kidney can filter out the
ammonia and convert it into a less
toxic urea along with excess water
and salt.
Urea, excess water and salt collect and
stored in the urinary bladder as urine.
Urine is then released out the body
through the urogenital opening.
Urinary bladder
High
Water moves from high to low.
A large amount of water moves
into the fresh water fish from
its environment. Therefore
they excrete large amounts of
urine constantly.
Low
Low
Low
Only a small amount of water
moves into the salt water fish
from its environment. Therefore
they excrete very small amounts
of urine.