Transcript Sheep Heart Dissection - Ms. Lee`s Classes @ JICHS

Sheep Heart
Dissection
SAFETY REMINDERS:
*Scalpels are very sharp—always cut
AWAY from yourself, with no fingers in
the way
*Putting on/taking off scalpels is just as
dangerous—ask for help if you’re
unsure!
*When you have gloves on, don’t touch
anything you can’t wash---if you touch
your pencil and get formalin on it, then
put that same pencil in your mouth
tomorrow….
1. Gather your dissection equipment and a
sheep heart.
2. Rinse the sheep heart thoroughly with
cold water to remove excess
preservatives and to flush out blood
clots.
3. If the pericardial sac is intact, then
remove the outer layer from its
attachment points.
4. Carefully pull the visceral pericardium
(epicardium) away from the myocardium.
How are the parietal and visceral pericardial
layers different?
5. Examine the external surface of the
heart. Notice the accumulation of
ADIPOSE tissue.
This adipose usually accumulates along
the boundaries of the heart chambers
and along the coronary arteries.
Remove as much adipose as possible.
Now you should be able to identify the
APEX (bottom left "point" of the heart)
and the AURICLES (earlike flaps
projecting from the atria).
Carefully scrape away a little adipose tissue
so you can see the coronary arteries.
Anterior view
Right auricle
Pulmonary
trunk
Right atrium
Left auricle
Left atrium
Right ventricle
Interventricular
septum
Left ventricle
Superior view
Superior vena
cava
Aorta
Pulmonary
trunk
Pulmonary
vein
5. Squeeze each ventricle.
Which is thicker?
That’s the LEFT VENTRICLE—Why’s it
thicker than the right?
Pumps blood to the entire body, through the
systemic circuit
The right ventricle pumps only to the lungs
through the pulmonary circuit.
6. Locate the PULMONARY
TRUNK & AORTA on the
superior aspect of the
heart.
The pulmonary trunk
divides into the left and
right pulmonary arteries.
The aorta will be thicker
walled and be just
behind the pulmonary
trunk.
Clear the adipose away
from these arteries.
LIGAMENTUM
ARTERIOSUM
(bypasses the lungs in
fetus, ductus
arteriosus, pulmonary
trunk and aorta
connection)
10.Pulmonary trunk—cut through
anterior wall until you see WHICH
valve?
PULMONARY SEMILUNAR VALVE
Extend the cut through pulm trunk into
Rt ventricle
SCISSORS CUT down/around/up through AV
valve—cut alongside the probe to see
internal right atrium and WHICH valve?
TRICUSPID
(RIGHT ATRIOVENTRICULAR VALVE)
9. Probe into the superior vena cava
through right atrium out the inferior vena
cava
Frontal section
Right atrium
Tricuspid AV
valve (chordae
tendinae,
muscles
Right ventricle
w/thinner
myocardium
Interventricular
septum
Pulmonary trunk via
pulmonary SL valve
Pulmonary veins
into left atrium
Bicuspid AV
valve
w/chordae
tendinae,
papillary
muscles
Aortic SL
valve, out aorta
Left ventricle
w/thicker
myocardium
11. Pin back the cut edges of superior vena
cava, right atrium, right ventricle
12.Right ventricle—papillary muscles,
chordae tendineae, tricuspid valve
Dispose of solid matter in
biohazard bag
Wash ALL PINS, TRAYS,
INSTRUMENTS, return to proper
place.
Gloves—dispose of in biohazard
bag.
WASH HANDS…
Sheep heart website
• http://www.gwc.maricopa.edu/class/bio202
/heart/anthrt.htm