This document provides instructions for dissecting a sheep heart specimen to view its internal structures. It describes making cuts along the superior vena cava and pulmonary vein to open the heart and examine the four chambers and major blood vessels, including the left and right ventricles, aorta, and pulmonary artery. Key anatomical features discussed are the heart valves, chordae tendinae that hold the valves in place, and the thicker walls of the left ventricle compared to the right ventricle.

1. LS2BFET
UNIT 1
PRACTICAL 1

2. FRONT SIDE BACK SIDE
SEPTUM
RIGHT
VENTRICLE
LEFT
VENTRICLE

3. AURICLE
PULMONARY
ARTERY

4.  • the pulmonary trunk
(artery),
• aorta,
• superior vena cava, and the
• pulmonary vein.

5. Criss-cross each other, with the pulmonary ARTERY in the front

6.  The two major veins - backside
 Pulmonary vein as it enters the left atrium.
 The superior vena cava enters the right atrium.

7.  Use the superior vena cava and pulmonary
vein as guides for where to cut.You are
basically going to be cutting each side of the
heart so that you can look inside.

8.  Your colour pencils you used to mark the
heart in step 2 can also now be used to see
where those vessels connect within the heart.
 For instance, the aorta pencil can now be
seen ending in the left ventricle.
 You can also now see how much thicker the
walls of the left ventricle are compared to
the right ventricle. ???

10.  Chordae tendinae
 These tendons hold the heart valves in place,
sometimes they are called the "heartstrings".
 The valves were probably cut when the heart
was opened, but if you follow the "cords"
they should lead you to a thin flap that is the
atrioventricular (bicuspid) valve.
 You can find a similar valve on the right side
of the heart (tricuspid).

13. ENJOY!