Transcript Frog Dissection new - nicolejohnson-garric

Frog Dissection!
Frog Background
Animal Class: Amphibian
Where frogs live:
Many live on land, but they must return to water
to reproduce because eggs are laid and fertilized in
water.
Body:
Head- are two nostrils; two eardrums; and two
eyes that have three eyelids! The third eyelid,
called the nictitating membrane, and it is
transparent.
Mouth- two openings into the nostrils; two
vomerine teeth in the middle of the roof of
the mouth; and two maxillary teeth at the sides of
the mouth.
Before you cut
Look at the eyes,
ears, forearms,
Inside mouth
Skeletal and Muscular
• The frog’s skeletal and muscular systems
consist of its framework of bones and joints,
to which nearly all the voluntary muscles of
the body are attached. Voluntary muscles,
which are those over which the frog has
control, occur in pairs of flexors and
extensors. When a flexor of a leg or other
body part contracts, that part is bent. When
the extensor of that body part contracts, the
part straightens.
No ribs!
Respiratory System….just like us!
• The frog respiratory system consists of…
-nostrils to let air in
- larynx that connects to
two lungs with alveoli
-lining of the lungs are also filled with
capillaries just like us!
Circulatory System…not quite like us
Frog
3 chamber heart with
two atria, and one
ventricle.
Human
4 chamber heart
with two atria, and
two ventricles.
BOTH
Blood is carried to the heart in vessels called veins.
Veins from different parts of the body enter the right
and left atria. Blood from both atria goes into the
ventricle and then is pumped into the arteries, which
are blood vessels that carry blood away from the
heart.
Urinary System…you get the idea!
Both: consists of the kidneys, ureters, bladder,
Remember-The kidneys are organs that
excrete urine. Connected to each kidney is a
ureter, a tube through which urine passes
into the urinary bladder, a sac that stores
urine until it passes out of the body.
Leaves the frog body through Leaves the human body through
the….
the….
cloaca
urethra
Digestive System….buuurp!
• Just like us, when a frog eats the food will
pass through…
-a mouth with a tongue that leads to the pharynx, or
throat
- an esophagus, where swallowed food moves into
the stomach
- Food then moves in small intestine, where most of
the digestion and absorption of food into the
bloodstream takes place
-Any indigestible materials pass through the large
intestine and then into the cloaca
Nervous System
Do we have a frog nervous system or do
they have a human nervous system?
The CNS of the frog consists of the brain, which
is enclosed in the skull, and the spinal cord,
which is enclosed in the backbone. Nerves
branch out from the spinal cord.
Time to cut it out!
Safety
1. You are to wear apron, gloves, and goggles the entire
block.
2. You MUST stay in the group you have been assigned the
entire block.
3. Only ONE person may use the scalpel at a time.
4. When I say clean up you MUST follow the clean up
procedure on the board.
5. You may not PLAY WITH or PUNCTURE the organs in the
frog.
6. Once you have cut the frog open you MAY NOT cut it
anymore unless permitted
7. If you put yourself or others in danger you WILL be sent
to another classroom to do book work and you WILL
receive a zero on the lab.
To determine the frog’s sex, look at the hand
digits, or fingers, on its forelegs. A male frog
usually has thick pads on its "thumbs," which is
one external difference between the sexes, as
shown in the diagram below. Male frogs are also
usually smaller than female frogs.
In lab section of notebook draw the differences.
In lab section draw incisions (There will only be three!)
Once cut you will pin back flaps to the tray.
After cutting skin…
On paper
Watch a dissection
• Video of dissection
• Step by step instructions
1. Place the frog inside the zip lock bag and then
place it in the big trash can by the door
2. Remove gloves and place them in the trash can
by the door
3. Wash the trays and the dissecting trays and dry
them with paper towel
4. Place the dissecting tools inside the “black”
container provided
5. Use the wipes to clean goggle
6. Use wipes to clean the table tops
7. Wash your hands at the assigned stations
8. Go through checklist #2