Heart Dissection
Tutorial
The hearts have already
been cut open and are
wrapped in a damp paper
towel in zip lock bags.
There are 2 at your lab
table.
Choose the period
number on the bag for
your specimen. The
specimen should be
returned the way you
found it.
DO NOT THROW IT
Heart Dissection
Tutorial
You will not need the
dissecting tools
today. Your only tool
is a straw (explained
later) – do not
destroy the straws!
Do not remove any
parts from the heart
or tear it apart!
Heart Dissection
Tutorial
WEAR EYE
PROTECTION
AND GLOVES!
Heart Dissection
Tutorial
As you go through
this tutorial, make
note of any parts
you had trouble
finding and bring
this next week
when we will look
at the hearts
again.
First determine the anterior
and posterior sides of your
sheep heart.
This is the anterior side. Note
the PULMONARY ARTERY
shown here with arrow. Find
this on your heart.
Note the fat on the surface.
Also note the blood vessels
that are embedded in the
external heart muscle. These
are the coronary arteries and
veins.
The red one is called the
WIDOW MAKER. WHY?
These purplish structures are
the auricles. They
communicate with the atria
chambers.
Your heart
does not have
all of the aorta
attached. You
are
responsible
for knowing
these
branches off
the aorta
shown in the
yellow boxes.
Right side
Right side
Left side
Left side
Thicker wall
Thicker wall
When you have examined the outside of the
heart, I will cut the heart in half as shown
Right side
Right side
Left side
Left side
Thicker wall
Thicker wall
Examine your open heart. Try to keep in mind which is the anterior
side vs. the posterior side. Note the difference in the thickness of the
walls. The Left side has a thicker wall because it is the main pump
having to move blood through the entire body.
Right
atrium
Left
atrium
Tricuspid
valve
Bicuspid valve
Chordae
tendinae
Right
ventricle
Papillary
muscle
Interventricular
septum
Left ventricle
Now open the heart as
shown and work with
either the posterior or
anterior side (choose the
side you can see these
structures in the bes)>
Right
atrium
Left
atrium
Tricuspid
valve
Bicuspid valve
Chordae
tendinae
Right
ventricle
Papillary
muscle
Interventricular
septum
Left ventricle
Now find all of these labeled
parts. Note the Chordae
Tendinae. These are threadlike bands of fibrous tissue
which attach on one end to
the edges of the tricuspid and
mitral valves of the heart and
on the other end to the
papillary muscles. the
papillary muscles of the heart
serve to limit the movements
of the mitral and tricuspid
valves. These muscles
contract to tighten the
chordae tendineae, which in
turn prevent inversion of the
valves.
Pulmonary
valve
Aortic
valve
CLOSER LOOK
ATof
Area
CHORDAE
cutaway
TENDINEAE AND
Mitral
PAPILLARY MUSCLE.
valve
Tricuspid
valve
Chordae tendineae
attached to tricuspid valve flap
Papillary
muscle
Figure 18.8c
Now you are going to use your finger or the straw to trace a drop of blood through
the heart naming all of the parts.
Now you are going to use your finger to trace a drop of blood through the heart
naming all of the parts. Begin at the posterior side of the heart and find the inferior
and superior vena cavae. Put your fingers through these and note that your finger
enters the right artrium. If you have problems finding the vena cavae, stick your
finger into the posterior right atrium chamber and find the vena cavae as it exits
this chamber. There are 2 vena cavae – find both.
Now from the
right atrium,
find the
tricuspid
valve, and
then the right
ventricle .
You will not be able to
see the pulmonary
semilunar valve, but it
is embedded in the
the heart tissue and it
is not exposed. To
find the exit from the
right ventricle, go to
the front of the heart
and place your finger
into the right ventricle
at an angle. See if
you can exit from
this area into the
pulmonary artery
which is number 18
on this specimen.
The blood exits the pulmonary artery, low in oxygen and now goes to
lungs. From there it will drop of carbon dioxide and pick up oxygen.
This oxygenated blood will now be channeled back to the heart via
the pulmonary veins. See diagram below. The yellow arrows show
the pulmonary artery.
If your are having trouble finding the
pulmonary artery, turn your heart to the
anterior side and stick your finger down
the pulmonary artery and watch where
it comes into the right ventricle. The
pulmonary semilunar valve is hidden
under the heart tissue. This is the only
valve that you will not be able to see.
The blood has traveled to the lungs to pick up oxygen. This
oxygenated blood will now be channeled back to the heart via
the pulmonary veins. The pulmonary veins are going to be
seen as one hole in the posterior side of the heart entering
the left atrium. See circled area.
Now from the
left atrium,
find the
bicuspid valve
(also called
mitral), and
then the left
ventricle .
The blood goes from the left ventricle through the
semilunar aortic valve and then into the aorta.
The aorta distributes oxygenated blood to all
parts of the body.
aorta
21 = aortic
semilunar valve
After the blood travels to the body cells,
the deoxygenated blood is carried by the
vena cavae into the right atrium and we
are back to where we started.
Now use your list to see if you can trace
a drop of blood through the heart.
When you are finished, go to the heart
review (next slides) and LEARN THE
PARTS!!!
HEART
ANATOMY
REVIEW
Name this
specific
valve
circled in
yellow.
Bicuspid or mitral
valve
Name this
chamber
(yellow
arrow).
Right ventricle
Name the
chamber
circled in
yellow.
Left ventricle
Name this
specific blood
vessel
highlighted in
yellow.
Pulmonary artery
Name the
specific
blood
vessel
highlighted
in yellow.
aorta
Name this
specific part
highlighted in
yellow.
Interventricular
septum
Name the
valve that
would be in
the area
circled by
yellow.
Aortic semilunar
valve
Name
the
blood
vessel
circled in
yellow.
Pulmonary artery
After blood leaves
the right ventricle,
what valve does it
pass through?
Pulmonary
semilunar valve
What heart
chamber does
the vena cavae
enter?
What blood
vessel carries
blood from the
lungs to the
heart? Pulmonary vein
What valve leads
into the
pulmonary
artery?
Pulmonary
semilunar valve
Name this string-like
structure (pink arrow). .
Chordae tendinae
inferior and superior vena
cavae
right atrium
tricuspid valve
right ventricle
pulmonary semilunar valve
pulmonary artery
lungs
pulmonary veins
left atrium
bicuspid valve
left ventricle
aortic semilunar valve
aorta
body
Name this bulging area
(pink arrow).
Papillary
muscle
Name the red
blood vessels on
surface of heart.
Coronary
arteries
Name the blue
blood vessels on
surface of heart.
Coronary
veins
Name the
specific vessel
# 1.
Brachiocephalic
artery
25. Name the
specific vessel
# 2.
Left common
carotid artery
Name the
specific vessel
# 3.
Left subclavian
artery
Name the
specific valve #
19.
Pulmonary
semilunar valve
THE END