Transcript Frog Dissection

Sheep Heart
Dissection
Objectives
By the end of this lesson, students will be
able to:
• Demonstrate proper dissection safety
techniques
• Identify the right and left sides of the heart
• Identify the parts of the heart: auricles,
superior vena cava, pulmonary vein, aorta,
left ventricle, pulmonary artery, bicuspid
and tricuspid valve.
• Measure the diameter of the aorta,
pulmonary trunk, left atrium, left ventricle
and right ventricle.
• Compare and contrast the structure of a
sheep heart to a human heart
Arkansas Frameworks
Grade 6
Grade 7
Grade 8
LS.2.6.1
LS.7.1.2
LS.8.1.8
LS.2.6.2
LS.7.1.3
LS.2.6.3
LS.7.1.4
LS.2.6.4
LS.2.6.6
Why Dissect?
Dissection allows students to:
• Practice safety procedures
• Construct science process skills
• Organize the hierarchal
relationships of tissues, organs,
organ systems and organisms
• Compare similarities and
differences among organisms
• Connect organism complexity to
its diversity
Materials
• Sheep heart specimen
• Dissection tray or
Styrofoam meat tray
• Dissection kit with
scissors, pins, scalpels,
tweezers and probes
• Gloves
• Goggles
• Plastic aprons
• Student worksheets
General Safety Rules
• The classroom should
be well ventilated
• Work space should be
flat and free of
unnecessary materials
• All equipment should
be clean and unbroken
• ABSOLUTELY no eating,
drinking or gum
chewing during
dissection activities
Sharp Instrument Safety
• Prepare a container for disposal of
broken instruments or glassware
• Dispose of the container intact and
replace with a new one to prevent
others from being cut
• Inventory all sharp items to ensure
all objects remain in the classroom
• Ensure that students use sharp
instruments properly.
• Remind students they should always
cut away from themselves and
others
Before we proceed
While dissecting, be respectful of your
lab partners and of the specimen you
are about to explore, observe and
learn from.
Take extra care with your dissection
tools. Your scissors are your most
important tool, but be sure to handle
them carefully and always double
check before cutting.
If you have any questions, please ask.
Attire
• Wear Gloves
• Wear Aprons
• Wear Goggles (ANSI
Z87.1)
Always!! No
Exceptions!!!!
Interesting Facts
Sheep have a four
chambered heart, just like
you. By studying the
anatomy of a sheep’s
heart, you can learn about
how your own heart
pumps blood through your
body and keeps you alive.
Interesting Facts
• Most heart diagrams
show the left atrium
and ventricle on the
right side of the
diagram. Imagine the
heart in the body of a
person facing you. The
left side of their heart
is on their left, but
Right
Side
since you are facing
them, it is on your
right.
Left
Side
External Anatomy
• Identify the right and left sides
of the heart. On one side of the
heart you will see a diagonal line
of blood vessels that divide the
heart.
• The half that includes all of the
apex (pointed end) of the heart
is the left side.
• Confirm this by squeezing each
half of the heart. The left half
will feel much firmer and more
muscular than the right side. Right
Side
Apex
Left
Side
External Anatomy
• Turn the heart so that
the right side is on your
right, as if it were in your
body.
• Examine the flaps of
darker tissue on the top
of the heart.
• These ear-like flaps are
called auricles.
Auricle
External Anatomy
• Find the large opening
at the top of the heart
next to the right auricle.
• This is the opening to
the superior vena cava.
• Stick a probe down the
vessel. You should feel
it open into the right
atrium.
Superior
Vena
Cava
Auricle
External Anatomy
• A little down and to
the left of the
superior vena cava,
there is another
blood vessel opening.
• Insert your probe into
this. It should also
lead to the right
atrium. This is the
inferior vena cava.
Superior
Vena Cava
Inferior
Vena Cava
Inferior
Vena
Cava
External Anatomy
• You can also see
another blood
vessel next to the
left auricle. This
is the pulmonary
vein.
Pulmonary
Vein
Inferior
Vena
Cava
Superior
Vena
Cava
External Anatomy
• Sticking straight up
from the center of the
heart is the largest
blood vessel you will
see. This is the aorta.
The aorta takes
oxygenated blood
from the left ventricle
to the rest of the body.
Aorta
Left
Ventricle
External Anatomy
• Behind and to
the left of the
aorta there is
another large
vessel. This is
the pulmonary
artery.
Pulmonary
Artery
Incision 1
• Insert your dissecting
scissors or scalpel
into the superior
vena cava and make
an incision down
through the wall of
the right atrium and
ventricle, as shown
by the dotted line in
the picture.
Chordae
Tendinae
Tricuspid
Valve
Moderator
Band
Papillary
Muscle
Incision 2
• Insert your probe
into the
pulmonary artery
and see it come
through the right
ventricle. Make
an incision down
through this
artery.
Pulmonary
Artery
Pulmonary
Semilunar
Valve
Observe and Measure
• Observe the right half of the heart.
• Identify the following:
–
–
–
–
Tricuspid valve
Pulmonary semilunar valve
Papillary muscles
Chordae Tendinae
• Measure the following:
– Diameter of the right atrium and
ventricle
– Wall thickness of the right atrium
and ventricle
– Diameter of the aorta and pulmonary
trunk
Incision 3
• Insert your
dissecting scissors
or scalpel into the
left auricle at the
base of the aorta
and make an
incision down
through the wall of
the left atrium and
ventricle as shown
by the line.
Chordae
Tendinae
Papillary
Muscle
Bicuspid
Valve
Incision 4
• Insert a probe
into the aorta
and observe
where it
connects to the
left ventricle.
Make an
incision up
through the
aorta.
Observation
• Observe the left side of
the heart.
• Identify the following:
–
–
–
–
Mitral or Bicuspid valve
Aortic Semilunar valve
Papillary muscles
Chordae tendinae
• Measure the following:
– Diameter of the left
atrium and ventricle
– Wall thickness of the left
atrium and ventricle.
Clean Up
• Place all dissecting specimens and
parts into approved container
provided by the instructor.
• Wash dissecting equipment and
trays in dilute bleach solution
provided by the instructor.
• Dry equipment thoroughly to
prevent rusting.
• Clean table tops with dilute bleach
solution provided by the instructor.
• Wash hands thoroughly before
leaving the classroom.
Resources
Color Me Heart
www.childrenheartinstitute.org/kidsonly/h
eartflw.htm
Heart House
www.childrenheartinstitute.org/kidsonly/h
earthse.htm
Heart Dissection Lab
www.hometrainingtools.com/articles/heart
-dissection-project.html
Heart Anatomy
www.enchantedlearning.com/subjects/anat
omy/heart labelinterior/label.shtml
Resources
Heart Lessons
http://www.smmm.org/heart/lessons/
heartDiagram.htm
Animations/Interactives
http://www.smm.org/heart/heart/top.
html
Heart Diagram
http://classroom.kidshealth.org/classro
om/6yo8/body/systems/cardiovascul
ar_handout1.pdf
Color Heart Diagram
www.heartfoundation.org.au/documen
t/NHF/heartimage.pdf